Changelog

0.57 (2021-06-05)

Warning

This release fixes a reflected cross-site scripting security hole with the ?_trace=1 feature. You should upgrade to this version, or to Datasette 0.56.1, as soon as possible. (#1360)

In addition to the security fix, this release includes ?_col= and ?_nocol= options for controlling which columns are displayed for a table, ?_facet_size= for increasing the number of facet results returned, re-display of your SQL query should an error occur and numerous bug fixes.

New features

  • If an error occurs while executing a user-provided SQL query, that query is now re-displayed in an editable form along with the error message. (#619)
  • New ?_col= and ?_nocol= parameters to show and hide columns in a table, plus an interface for hiding and showing columns in the column cog menu. (#615)
  • A new ?_facet_size= parameter for customizing the number of facet results returned on a table or view page. (#1332)
  • ?_facet_size=max sets that to the maximum, which defaults to 1,000 and is controlled by the the max_returned_rows setting. If facet results are truncated the … at the bottom of the facet list now links to this parameter. (#1337)
  • ?_nofacet=1 option to disable all facet calculations on a page, used as a performance optimization for CSV exports and ?_shape=array/object. (#1349, #263)
  • ?_nocount=1 option to disable full query result counts. (#1353)
  • ?_trace=1 debugging option is now controlled by the new trace_debug setting, which is turned off by default. (#1359)

Bug fixes and other improvements

  • Custom pages now work correctly when combined with the base_url setting. (#1238)
  • Fixed intermittent error displaying the index page when the user did not have permission to access one of the tables. Thanks, Guy Freeman. (#1305)
  • Columns with the name "Link" are no longer incorrectly displayed in bold. (#1308)
  • Fixed error caused by tables with a single quote in their names. (#1257)
  • Updated dependencies: pytest-asyncio, Black, jinja2, aiofiles, click, and itsdangerous.
  • The official Datasette Docker image now supports apt-get install. (#1320)
  • The Heroku runtime used by datasette publish heroku is now python-3.8.10.

0.56.1 (2021-06-05)

Warning

This release fixes a reflected cross-site scripting security hole with the ?_trace=1 feature. You should upgrade to this version, or to Datasette 0.57, as soon as possible. (#1360)

0.56 (2021-03-28)

Documentation improvements, bug fixes and support for SpatiaLite 5.

  • The SQL editor can now be resized by dragging a handle. (#1236)
  • Fixed a bug with JSON faceting and the __arraycontains filter caused by tables with spaces in their names. (#1239)
  • Upgraded httpx dependency. (#1005)
  • JSON faceting is now suggested even if a column contains blank strings. (#1246)
  • New datasette.add_memory_database() method. (#1247)
  • The Response.asgi_send() method is now documented. (#1266)
  • The official Datasette Docker image now bundles SpatiaLite version 5. (#1278)
  • Fixed a no such table: pragma_database_list bug when running Datasette against SQLite versions prior to SQLite 3.16.0. (#1276)
  • HTML lists displayed in table cells are now styled correctly. Thanks, Bob Whitelock. (#1141, #1252)
  • Configuration directory mode now correctly serves immutable databases that are listed in inspect-data.json. Thanks Campbell Allen and Frankie Robertson. (#1031, #1229)

0.55 (2021-02-18)

Support for cross-database SQL queries and built-in support for serving via HTTPS.

  • The new --crossdb command-line option causes Datasette to attach up to ten database files to the same /_memory database connection. This enables cross-database SQL queries, including the ability to use joins and unions to combine data from tables that exist in different database files. See Cross-database queries for details. (#283)
  • --ssl-keyfile and --ssl-certfile options can be used to specify a TLS certificate, allowing Datasette to serve traffic over https:// without needing to run it behind a separate proxy. (#1221)
  • The /:memory: page has been renamed (and redirected) to /_memory for consistency with the new /_internal database introduced in Datasette 0.54. (#1205)
  • Added plugin testing documentation on Using pdb for errors thrown inside Datasette. (#1207)
  • The official Datasette Docker image now uses Python 3.7.10, applying the latest security fix for that Python version. (#1235)

0.54.1 (2021-02-02)

  • Fixed a bug where ?_search= and ?_sort= parameters were incorrectly duplicated when the filter form on the table page was re-submitted. (#1214)

0.54 (2021-01-25)

The two big new features in this release are the _internal SQLite in-memory database storing details of all connected databases and tables, and support for JavaScript modules in plugins and additional scripts.

For additional commentary on this release, see Datasette 0.54, the annotated release notes.

The _internal database

As part of ongoing work to help Datasette handle much larger numbers of connected databases and tables (see Datasette Library) Datasette now maintains an in-memory SQLite database with details of all of the attached databases, tables, columns, indexes and foreign keys. (#1150)

This will support future improvements such as a searchable, paginated homepage of all available tables.

You can explore an example of this database by signing in as root to the latest.datasette.io demo instance and then navigating to latest.datasette.io/_internal.

Plugins can use these tables to introspect attached data in an efficient way. Plugin authors should note that this is not yet considered a stable interface, so any plugins that use this may need to make changes prior to Datasette 1.0 if the _internal table schemas change.

Named in-memory database support

As part of the work building the _internal database, Datasette now supports named in-memory databases that can be shared across multiple connections. This allows plugins to create in-memory databases which will persist data for the lifetime of the Datasette server process. (#1151)

The new memory_name= parameter to the Database class can be used to create named, shared in-memory databases.

JavaScript modules

JavaScript modules were introduced in ECMAScript 2015 and provide native browser support for the import and export keywords.

To use modules, JavaScript needs to be included in <script> tags with a type="module" attribute.

Datasette now has the ability to output <script type="module"> in places where you may wish to take advantage of modules. The extra_js_urls option described in Custom CSS and JavaScript can now be used with modules, and module support is also available for the extra_body_script() plugin hook. (#1186, #1187)

datasette-leaflet-freedraw is the first example of a Datasette plugin that takes advantage of the new support for JavaScript modules. See Drawing shapes on a map to query a SpatiaLite database for more on this plugin.

Code formatting with Black and Prettier

Datasette adopted Black for opinionated Python code formatting in June 2019. Datasette now also embraces Prettier for JavaScript formatting, which like Black is enforced by tests in continuous integration. Instructions for using these two tools can be found in the new section on Code formatting in the contributors documentation. (#1167)

Other changes

  • Datasette can now open multiple database files with the same name, e.g. if you run datasette path/to/one.db path/to/other/one.db. (#509)
  • datasette publish cloudrun now sets force_https_urls for every deployment, fixing some incorrect http:// links. (#1178)
  • Fixed a bug in the example nginx configuration in Running Datasette behind a proxy. (#1091)
  • The Datasette Ecosystem documentation page has been reduced in size in favour of the datasette.io tools and plugins directories. (#1182)
  • The request object now provides a request.full_path property, which returns the path including any query string. (#1184)
  • Better error message for disallowed PRAGMA clauses in SQL queries. (#1185)
  • datasette publish heroku now deploys using python-3.8.7.
  • New plugin testing documentation on Testing outbound HTTP calls with pytest-httpx. (#1198)
  • All ?_* query string parameters passed to the table page are now persisted in hidden form fields, so parameters such as ?_size=10 will be correctly passed to the next page when query filters are changed. (#1194)
  • Fixed a bug loading a database file called test-database (1).sqlite. (#1181)

0.53 (2020-12-10)

Datasette has an official project website now, at https://datasette.io/. This release mainly updates the documentation to reflect the new site.

  • New ?column__arraynotcontains= table filter. (#1132)
  • datasette serve has a new --create option, which will create blank database files if they do not already exist rather than exiting with an error. (#1135)
  • New ?_header=off option for CSV export which omits the CSV header row, documented here. (#1133)
  • "Powered by Datasette" link in the footer now links to https://datasette.io/. (#1138)
  • Project news no longer lives in the README - it can now be found at https://datasette.io/news. (#1137)

0.52.5 (2020-12-09)

  • Fix for error caused by combining the _searchmode=raw and ?_search_COLUMN parameters. (#1134)

0.52.4 (2020-12-05)

  • Show pysqlite3 version on /-/versions, if installed. (#1125)
  • Errors output by Datasette (e.g. for invalid SQL queries) now go to stderr, not stdout. (#1131)
  • Fix for a startup error on windows caused by unnecessary from os import EX_CANTCREAT - thanks, Abdussamet Koçak. (#1094)

0.52.3 (2020-12-03)

  • Fixed bug where static assets would 404 for Datasette installed on ARM Amazon Linux. (#1124)

0.52.2 (2020-12-02)

  • Generated columns from SQLite 3.31.0 or higher are now correctly displayed. (#1116)
  • Error message if you attempt to open a SpatiaLite database now suggests using --load-extension=spatialite if it detects that the extension is available in a common location. (#1115)
  • OPTIONS requests against the /database page no longer raise a 500 error. (#1100)
  • Databases larger than 32MB that are published to Cloud Run can now be downloaded. (#749)
  • Fix for misaligned cog icon on table and database pages. Thanks, Abdussamet Koçak. (#1121)

0.52.1 (2020-11-29)

  • Documentation on Testing plugins now recommends using datasette.client. (#1102)
  • Fix bug where compound foreign keys produced broken links. (#1098)
  • datasette --load-module=spatialite now also checks for /usr/local/lib/mod_spatialite.so. Thanks, Dan Peterson. (#1114)

0.52 (2020-11-28)

This release includes a number of changes relating to an internal rebranding effort: Datasette's configuration mechanism (things like datasette --config default_page_size:10) has been renamed to settings.

  • New --setting default_page_size 10 option as a replacement for --config default_page_size:10 (note the lack of a colon). The --config option is deprecated but will continue working until Datasette 1.0. (#992)
  • The /-/config introspection page is now /-/settings, and the previous page redirects to the new one. (#1103)
  • The config.json file in Configuration directory mode is now called settings.json. (#1104)
  • The undocumented datasette.config() internal method has been replaced by a documented .setting(key) method. (#1107)

Also in this release:

  • New plugin hook: database_actions(datasette, actor, database), which adds menu items to a new cog menu shown at the top of the database page. (#1077)
  • datasette publish cloudrun has a new --apt-get-install option that can be used to install additional Ubuntu packages as part of the deployment. This is useful for deploying the new datasette-ripgrep plugin. (#1110)
  • Swept the documentation to remove words that minimize involved difficulty. (#1089)

And some bug fixes:

  • Foreign keys linking to rows with blank label columns now display as a hyphen, allowing those links to be clicked. (#1086)
  • Fixed bug where row pages could sometimes 500 if the underlying queries exceeded a time limit. (#1088)
  • Fixed a bug where the table action menu could appear partially obscured by the edge of the page. (#1084)

0.51.1 (2020-10-31)

  • Improvements to the new Binary data documentation page.

0.51 (2020-10-31)

A new visual design, plugin hooks for adding navigation options, better handling of binary data, URL building utility methods and better support for running Datasette behind a proxy.

New visual design

Datasette is no longer white and grey with blue and purple links! Natalie Downe has been working on a visual refresh, the first iteration of which is included in this release. (#1056)

Screenshot showing Datasette's new visual look

Binary data

SQLite tables can contain binary data in BLOB columns. Datasette now provides links for users to download this data directly from Datasette, and uses those links to make binary data available from CSV exports. See Binary data for more details. (#1036 and #1034).

URL building

The new datasette.urls family of methods can be used to generate URLs to key pages within the Datasette interface, both within custom templates and Datasette plugins. See Building URLs within plugins for more details. (#904)

Running Datasette behind a proxy

The base_url configuration option is designed to help run Datasette on a specific path behind a proxy - for example if you want to run an instance of Datasette at /my-datasette/ within your existing site's URL hierarchy, proxied behind nginx or Apache.

Support for this configuration option has been greatly improved (#1023), and guidelines for using it are now available in a new documentation section on Running Datasette behind a proxy. (#1027)

Smaller changes

  • Wide tables shown within Datasette now scroll horizontally (#998). This is achieved using a new <div class="table-wrapper"> element which may impact the implementation of some plugins (for example this change to datasette-cluster-map).
  • New debug-menu permission. (#1068)
  • Removed --debug option, which didn't do anything. (#814)
  • Link: HTTP header pagination. (#1014)
  • x button for clearing filters. (#1016)
  • Edit SQL button on canned queries, (#1019)
  • --load-extension=spatialite shortcut. (#1028)
  • scale-in animation for column action menu. (#1039)
  • Option to pass a list of templates to .render_template() is now documented. (#1045)
  • New datasette.urls.static_plugins() method. (#1033)
  • datasette -o option now opens the most relevant page. (#976)
  • datasette --cors option now enables access to /database.db downloads. (#1057)
  • Database file downloads now implement cascading permissions, so you can download a database if you have view-database-download permission even if you do not have permission to access the Datasette instance. (#1058)
  • New documentation on Designing URLs for your plugin. (#1053)

0.50.2 (2020-10-09)

  • Fixed another bug introduced in 0.50 where column header links on the table page were broken. (#1011)

0.50.1 (2020-10-09)

  • Fixed a bug introduced in 0.50 where the export as JSON/CSV links on the table, row and query pages were broken. (#1010)

0.50 (2020-10-09)

The key new feature in this release is the column actions menu on the table page (#891). This can be used to sort a column in ascending or descending order, facet data by that column or filter the table to just rows that have a value for that column.

Plugin authors can use the new datasette.client object to make internal HTTP requests from their plugins, allowing them to make use of Datasette's JSON API. (#943)

New Deploying Datasette documentation with guides for deploying Datasette on a Linux server using systemd or to hosting providers that support buildpacks. (#514, #997)

Other improvements in this release:

  • Publishing to Google Cloud Run documentation now covers Google Cloud SDK options. Thanks, Geoffrey Hing. (#995)
  • New datasette -o option which opens your browser as soon as Datasette starts up. (#970)
  • Datasette now sets sqlite3.enable_callback_tracebacks(True) so that errors in custom SQL functions will display tracebacks. (#891)
  • Fixed two rendering bugs with column headers in portrait mobile view. (#978, #980)
  • New db.table_column_details(table) introspection method for retrieving full details of the columns in a specific table, see Database introspection.
  • Fixed a routing bug with custom page wildcard templates. (#996)
  • datasette publish heroku now deploys using Python 3.8.6.
  • New datasette publish heroku --tar= option. (#969)
  • OPTIONS requests against HTML pages no longer return a 500 error. (#1001)
  • Datasette now supports Python 3.9.

See also Datasette 0.50: The annotated release notes.

0.49.1 (2020-09-15)

  • Fixed a bug with writable canned queries that use magic parameters but accept no non-magic arguments. (#967)

0.49 (2020-09-14)

See also Datasette 0.49: The annotated release notes.

  • Writable canned queries now expose a JSON API, see JSON API for writable canned queries. (#880)
  • New mechanism for defining page templates with custom path parameters - a template file called pages/about/{slug}.html will be used to render any requests to /about/something. See Path parameters for pages. (#944)
  • register_output_renderer() render functions can now return a Response. (#953)
  • New --upgrade option for datasette install. (#945)
  • New datasette --pdb option. (#962)
  • datasette --get exit code now reflects the internal HTTP status code. (#947)
  • New raise_404() template function for returning 404 errors. (#964)
  • datasette publish heroku now deploys using Python 3.8.5
  • Upgraded CodeMirror to 5.57.0. (#948)
  • Upgraded code style to Black 20.8b1. (#958)
  • Fixed bug where selected facets were not correctly persisted in hidden form fields on the table page. (#963)
  • Renamed the default error template from 500.html to error.html.
  • Custom error pages are now documented, see Custom error pages. (#965)

0.48 (2020-08-16)

0.47.3 (2020-08-15)

  • The datasette --get command-line mechanism now ensures any plugins using the startup() hook are correctly executed. (#934)

0.47.2 (2020-08-12)

0.47.1 (2020-08-11)

  • Fixed a bug where the sdist distribution of Datasette was not correctly including the template files. (#930)

0.47 (2020-08-11)

  • Datasette now has a GitHub discussions forum for conversations about the project that go beyond just bug reports and issues.
  • Datasette can now be installed on macOS using Homebrew! Run brew install simonw/datasette/datasette. See Using Homebrew. (#335)
  • Two new commands: datasette install name-of-plugin and datasette uninstall name-of-plugin. These are equivalent to pip install and pip uninstall but automatically run in the same virtual environment as Datasette, so users don't have to figure out where that virtual environment is - useful for installations created using Homebrew or pipx. See Installing plugins. (#925)
  • A new command-line option, datasette --get, accepts a path to a URL within the Datasette instance. It will run that request through Datasette (without starting a web server) and print out the repsonse. See datasette --get for an example. (#926)

0.46 (2020-08-09)

Warning

This release contains a security fix related to authenticated writable canned queries. If you are using this feature you should upgrade as soon as possible.

  • Security fix: CSRF tokens were incorrectly included in read-only canned query forms, which could allow them to be leaked to a sophisticated attacker. See issue 918 for details.
  • Datasette now supports GraphQL via the new datasette-graphql plugin - see GraphQL in Datasette with the new datasette-graphql plugin.
  • Principle git branch has been renamed from master to main. (#849)
  • New debugging tool: /-/allow-debug tool (demo here) helps test allow blocks against actors, as described in Defining permissions with "allow" blocks. (#908)
  • New logo for the documentation, and a new project tagline: "An open source multi-tool for exploring and publishing data".
  • Whitespace in column values is now respected on display, using white-space: pre-wrap. (#896)
  • New await request.post_body() method for accessing the raw POST body, see Request object. (#897)
  • Database file downloads now include a content-length HTTP header, enabling download progress bars. (#905)
  • File downloads now also correctly set the suggested file name using a content-disposition HTTP header. (#909)
  • tests are now excluded from the Datasette package properly - thanks, abeyerpath. (#456)
  • The Datasette package published to PyPI now includes sdist as well as bdist_wheel.
  • Better titles for canned query pages. (#887)
  • Now only loads Python files from a directory passed using the --plugins-dir option - thanks, Amjith Ramanujam. (#890)
  • New documentation section on Publishing to Vercel.

0.45 (2020-07-01)

See also Datasette 0.45: The annotated release notes.

Magic parameters for canned queries, a log out feature, improved plugin documentation and four new plugin hooks.

Magic parameters for canned queries

Canned queries now support Magic parameters, which can be used to insert or select automatically generated values. For example:

insert into logs
  (user_id, timestamp)
values
  (:_actor_id, :_now_datetime_utc)

This inserts the currently authenticated actor ID and the current datetime. (#842)

Log out

The ds_actor cookie can be used by plugins (or by Datasette's --root mechanism) to authenticate users. The new /-/logout page provides a way to clear that cookie.

A "Log out" button now shows in the global navigation provided the user is authenticated using the ds_actor cookie. (#840)

Better plugin documentation

The plugin documentation has been re-arranged into four sections, including a brand new section on testing plugins. (#687)

  • Plugins introduces Datasette's plugin system and describes how to install and configure plugins.
  • Writing plugins describes how to author plugins, from one-off single file plugins to packaged plugins that can be published to PyPI. It also describes how to start a plugin using the new datasette-plugin cookiecutter template.
  • Plugin hooks is a full list of detailed documentation for every Datasette plugin hook.
  • Testing plugins describes how to write tests for Datasette plugins, using pytest and HTTPX.

New plugin hooks

Smaller changes

  • Cascading view permissons - so if a user has view-table they can view the table page even if they do not have view-database or view-instance. (#832)
  • CSRF protection no longer applies to Authentication: Bearer token requests or requests without cookies. (#835)
  • datasette.add_message() now works inside plugins. (#864)
  • Workaround for "Too many open files" error in test runs. (#846)
  • Respect existing scope["actor"] if already set by ASGI middleware. (#854)
  • New process for shipping Alpha and beta releases. (#807)
  • {{ csrftoken() }} now works when plugins render a template using datasette.render_template(..., request=request). (#863)
  • Datasette now creates a single Request object and uses it throughout the lifetime of the current HTTP request. (#870)

0.44 (2020-06-11)

See also Datasette 0.44: The annotated release notes.

Authentication and permissions, writable canned queries, flash messages, new plugin hooks and more.

Authentication

Prior to this release the Datasette ecosystem has treated authentication as exclusively the realm of plugins, most notably through datasette-auth-github.

0.44 introduces Authentication and permissions as core Datasette concepts (#699). This enables different plugins to share responsibility for authenticating requests - you might have one plugin that handles user accounts and another one that allows automated access via API keys, for example.

You'll need to install plugins if you want full user accounts, but default Datasette can now authenticate a single root user with the new --root command-line option, which outputs a one-time use URL to authenticate as a root actor (#784):

$ datasette fixtures.db --root
http://127.0.0.1:8001/-/auth-token?token=5b632f8cd44b868df625f5a6e2185d88eea5b22237fd3cc8773f107cc4fd6477
INFO:     Started server process [14973]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
INFO:     Uvicorn running on http://127.0.0.1:8001 (Press CTRL+C to quit)

Plugins can implement new ways of authenticating users using the new actor_from_request(datasette, request) hook.

Permissions

Datasette also now has a built-in concept of Permissions. The permissions system answers the following question:

Is this actor allowed to perform this action, optionally against this particular resource?

You can use the new "allow" block syntax in metadata.json (or metadata.yaml) to set required permissions at the instance, database, table or canned query level. For example, to restrict access to the fixtures.db database to the "root" user:

{
    "databases": {
        "fixtures": {
            "allow": {
                "id" "root"
            }
        }
    }
}

See Defining permissions with "allow" blocks for more details.

Plugins can implement their own custom permission checks using the new permission_allowed(datasette, actor, action, resource) hook.

A new debug page at /-/permissions shows recent permission checks, to help administrators and plugin authors understand exactly what checks are being performed. This tool defaults to only being available to the root user, but can be exposed to other users by plugins that respond to the permissions-debug permission. (#788)

Writable canned queries

Datasette's Canned queries feature lets you define SQL queries in metadata.json which can then be executed by users visiting a specific URL. https://latest.datasette.io/fixtures/neighborhood_search for example.

Canned queries were previously restricted to SELECT, but Datasette 0.44 introduces the ability for canned queries to execute INSERT or UPDATE queries as well, using the new "write": true property (#800):

{
    "databases": {
        "dogs": {
            "queries": {
                "add_name": {
                    "sql": "INSERT INTO names (name) VALUES (:name)",
                    "write": true
                }
            }
        }
    }
}

See Writable canned queries for more details.

Flash messages

Writable canned queries needed a mechanism to let the user know that the query has been successfully executed. The new flash messaging system (#790) allows messages to persist in signed cookies which are then displayed to the user on the next page that they visit. Plugins can use this mechanism to display their own messages, see .add_message(request, message, message_type=datasette.INFO) for details.

You can try out the new messages using the /-/messages debug tool, for example at https://latest.datasette.io/-/messages

Signed values and secrets

Both flash messages and user authentication needed a way to sign values and set signed cookies. Two new methods are now available for plugins to take advantage of this mechanism: .sign(value, namespace="default") and .unsign(value, namespace="default").

Datasette will generate a secret automatically when it starts up, but to avoid resetting the secret (and hence invalidating any cookies) every time the server restarts you should set your own secret. You can pass a secret to Datasette using the new --secret option or with a DATASETTE_SECRET environment variable. See Configuring the secret for more details.

You can also set a secret when you deploy Datasette using datasette publish or datasette package - see Using secrets with datasette publish.

Plugins can now sign values and verify their signatures using the datasette.sign() and datasette.unsign() methods.

CSRF protection

Since writable canned queries are built using POST forms, Datasette now ships with CSRF protection (#798). This applies automatically to any POST request, which means plugins need to include a csrftoken in any POST forms that they render. They can do that like so:

<input type="hidden" name="csrftoken" value="{{ csrftoken() }}">

register_routes() plugin hooks

Plugins can now register new views and routes via the register_routes() plugin hook (#819). View functions can be defined that accept any of the current datasette object, the current request, or the ASGI scope, send and receive objects.

Smaller changes

  • New internals documentation for Request object and Response class. (#706)
  • request.url now respects the force_https_urls config setting. closes (#781)
  • request.args.getlist() returns [] if missing. Removed request.raw_args entirely. (#774)
  • New datasette.get_database() method.
  • Added _ prefix to many private, undocumented methods of the Datasette class. (#576)
  • Removed the db.get_outbound_foreign_keys() method which duplicated the behaviour of db.foreign_keys_for_table().
  • New await datasette.permission_allowed() method.
  • /-/actor debugging endpoint for viewing the currently authenticated actor.
  • New request.cookies property.
  • /-/plugins endpoint now shows a list of hooks implemented by each plugin, e.g. https://latest.datasette.io/-/plugins?all=1
  • request.post_vars() method no longer discards empty values.
  • New "params" canned query key for explicitly setting named parameters, see Canned query parameters. (#797)
  • request.args is now a MultiParams object.
  • Fixed a bug with the datasette plugins command. (#802)
  • Nicer pattern for using make_app_client() in tests. (#395)
  • New request.actor property.
  • Fixed broken CSS on nested 404 pages. (#777)
  • New request.url_vars property. (#822)
  • Fixed a bug with the python tests/fixtures.py command for outputting Datasette's testing fixtures database and plugins. (#804)
  • datasette publish heroku now deploys using Python 3.8.3.
  • Added a warning that the register_facet_classes() hook is unstable and may change in the future. (#830)
  • The {"$env": "ENVIRONMENT_VARIBALE"} mechanism (see Secret configuration values) now works with variables inside nested lists. (#837)

The road to Datasette 1.0

I've assembled a milestone for Datasette 1.0. The focus of the 1.0 release will be the following:

  • Signify confidence in the quality/stability of Datasette
  • Give plugin authors confidence that their plugins will work for the whole 1.x release cycle
  • Provide the same confidence to developers building against Datasette JSON APIs

If you have thoughts about what you would like to see for Datasette 1.0 you can join the conversation on issue #519.

0.43 (2020-05-28)

The main focus of this release is a major upgrade to the register_output_renderer(datasette) plugin hook, which allows plugins to provide new output formats for Datasette such as datasette-atom and datasette-ics.

  • Redesign of register_output_renderer(datasette) to provide more context to the render callback and support an optional "can_render" callback that controls if a suggested link to the output format is provided. (#581, #770)
  • Visually distinguish float and integer columns - useful for figuring out why order-by-column might be returning unexpected results. (#729)
  • The Request object, which is passed to several plugin hooks, is now documented. (#706)
  • New metadata.json option for setting a custom default page size for specific tables and views, see Setting a custom page size. (#751)
  • Canned queries can now be configured with a default URL fragment hash, useful when working with plugins such as datasette-vega, see Setting a default fragment. (#706)
  • Fixed a bug in datasette publish when running on operating systems where the /tmp directory lives in a different volume, using a backport of the Python 3.8 shutil.copytree() function. (#744)
  • Every plugin hook is now covered by the unit tests, and a new unit test checks that each plugin hook has at least one corresponding test. (#771, #773)

0.42 (2020-05-08)

A small release which provides improved internal methods for use in plugins, along with documentation. See #685.

  • Added documentation for db.execute(), see await db.execute(sql, ...).
  • Renamed db.execute_against_connection_in_thread() to db.execute_fn() and made it a documented method, see await db.execute_fn(fn).
  • New results.first() and results.single_value() methods, plus documentation for the Results class - see Results.

0.41 (2020-05-06)

You can now create custom pages within your Datasette instance using a custom template file. For example, adding a template file called templates/pages/about.html will result in a new page being served at /about on your instance. See the custom pages documentation for full details, including how to return custom HTTP headers, redirects and status codes. (#648)

Configuration directory mode (#731) allows you to define a custom Datasette instance as a directory. So instead of running the following:

$ datasette one.db two.db \
  --metadata=metadata.json \
  --template-dir=templates/ \
  --plugins-dir=plugins \
  --static css:css

You can instead arrange your files in a single directory called my-project and run this:

$ datasette my-project/

Also in this release:

  • New NOT LIKE table filter: ?colname__notlike=expression. (#750)
  • Datasette now has a pattern portfolio at /-/patterns - e.g. https://latest.datasette.io/-/patterns. This is a page that shows every Datasette user interface component in one place, to aid core development and people building custom CSS themes. (#151)
  • SQLite PRAGMA functions such as pragma_table_info(tablename) are now allowed in Datasette SQL queries. (#761)
  • Datasette pages now consistently return a content-type of text/html; charset=utf-8". (#752)
  • Datasette now handles an ASGI raw_path value of None, which should allow compatibilty with the Mangum adapter for running ASGI apps on AWS Lambda. Thanks, Colin Dellow. (#719)
  • Installation documentation now covers how to Using pipx. (#756)
  • Improved the documentation for Full-text search. (#748)

0.40 (2020-04-21)

  • Datasette Metadata can now be provided as a YAML file as an optional alternative to JSON. See Using YAML for metadata. (#713)
  • Removed support for datasette publish now, which used the the now-retired Zeit Now v1 hosting platform. A new plugin, datasette-publish-now, can be installed to publish data to Zeit (now Vercel) Now v2. (#710)
  • Fixed a bug where the extra_template_vars(request, view_name) plugin hook was not receiving the correct view_name. (#716)
  • Variables added to the template context by the extra_template_vars() plugin hook are now shown in the ?_context=1 debugging mode (see template_debug). (#693)
  • Fixed a bug where the "templates considered" HTML comment was no longer being displayed. (#689)
  • Fixed a datasette publish bug where --plugin-secret would over-ride plugin configuration in the provided metadata.json file. (#724)
  • Added a new CSS class for customizing the canned query page. (#727)

0.39 (2020-03-24)

  • New base_url configuration setting for serving up the correct links while running Datasette under a different URL prefix. (#394)
  • New metadata settings "sort" and "sort_desc" for setting the default sort order for a table. See Setting a default sort order. (#702)
  • Sort direction arrow now displays by default on the primary key. This means you only have to click once (not twice) to sort in reverse order. (#677)
  • New await Request(scope, receive).post_vars() method for accessing POST form variables. (#700)
  • Plugin hooks documentation now links to example uses of each plugin. (#709)

0.38 (2020-03-08)

  • The Docker build of Datasette now uses SQLite 3.31.1, upgraded from 3.26. (#695)
  • datasette publish cloudrun now accepts an optional --memory=2Gi flag for setting the Cloud Run allocated memory to a value other than the default (256Mi). (#694)
  • Fixed bug where templates that shipped with plugins were sometimes not being correctly loaded. (#697)

0.37.1 (2020-03-02)

0.37 (2020-02-25)

  • Plugins now have a supported mechanism for writing to a database, using the new .execute_write() and .execute_write_fn() methods. Documentation. (#682)
  • Immutable databases that have had their rows counted using the inspect command now use the calculated count more effectively - thanks, Kevin Keogh. (#666)
  • --reload no longer restarts the server if a database file is modified, unless that database was opened immutable mode with -i. (#494)
  • New ?_searchmode=raw option turns off escaping for FTS queries in ?_search= allowing full use of SQLite's FTS5 query syntax. (#676)

0.36 (2020-02-21)

0.35 (2020-02-04)

  • Added five new plugins and one new conversion tool to the The Datasette Ecosystem.
  • The Datasette class has a new render_template() method which can be used by plugins to render templates using Datasette's pre-configured Jinja templating library.
  • You can now execute SQL queries that start with a -- comment - thanks, Jay Graves (#653)

0.34 (2020-01-29)

  • _search= queries are now correctly escaped using a new escape_fts() custom SQL function. This means you can now run searches for strings like park. without seeing errors. (#651)
  • Google Cloud Run is no longer in beta, so datasette publish cloudrun has been updated to work even if the user has not installed the gcloud beta components package. Thanks, Katie McLaughlin (#660)
  • datasette package now accepts a --port option for specifying which port the resulting Docker container should listen on. (#661)

0.33 (2019-12-22)

  • rowid is now included in dropdown menus for filtering tables (#636)
  • Columns are now only suggested for faceting if they have at least one value with more than one record (#638)
  • Queries with no results now display "0 results" (#637)
  • Improved documentation for the --static option (#641)
  • asyncio task information is now included on the /-/threads debug page
  • Bumped Uvicorn dependency 0.11
  • You can now use --port 0 to listen on an available port
  • New template_debug setting for debugging templates, e.g. https://latest.datasette.io/fixtures/roadside_attractions?_context=1 (#654)

0.32 (2019-11-14)

Datasette now renders templates using Jinja async mode. This means plugins can provide custom template functions that perform asynchronous actions, for example the new datasette-template-sql plugin which allows custom templates to directly execute SQL queries and render their results. (#628)

0.31.2 (2019-11-13)

  • Fixed a bug where datasette publish heroku applications failed to start (#633)
  • Fix for datasette publish with just --source_url - thanks, Stanley Zheng (#572)
  • Deployments to Heroku now use Python 3.8.0 (#632)

0.31.1 (2019-11-12)

  • Deployments created using datasette publish now use python:3.8 base Docker image (#629)

0.31 (2019-11-11)

This version adds compatibility with Python 3.8 and breaks compatibility with Python 3.5.

If you are still running Python 3.5 you should stick with 0.30.2, which you can install like this:

pip install datasette==0.30.2
  • Format SQL button now works with read-only SQL queries - thanks, Tobias Kunze (#602)
  • New ?column__notin=x,y,z filter for table views (#614)
  • Table view now uses select col1, col2, col3 instead of select *
  • Database filenames can now contain spaces - thanks, Tobias Kunze (#590)
  • Removed obsolete ?_group_count=col feature (#504)
  • Improved user interface and documentation for datasette publish cloudrun (#608)
  • Tables with indexes now show the CREATE INDEX statements on the table page (#618)
  • Current version of uvicorn is now shown on /-/versions
  • Python 3.8 is now supported! (#622)
  • Python 3.5 is no longer supported.

0.30.2 (2019-11-02)

  • /-/plugins page now uses distribution name e.g. datasette-cluster-map instead of the name of the underlying Python package (datasette_cluster_map) (#606)
  • Array faceting is now only suggested for columns that contain arrays of strings (#562)
  • Better documentation for the --host argument (#574)
  • Don't show None with a broken link for the label on a nullable foreign key (#406)

0.30.1 (2019-10-30)

  • Fixed bug where ?_where= parameter was not persisted in hidden form fields (#604)
  • Fixed bug with .JSON representation of row pages - thanks, Chris Shaw (#603)

0.30 (2019-10-18)

  • Added /-/threads debugging page
  • Allow EXPLAIN WITH... (#583)
  • Button to format SQL - thanks, Tobias Kunze (#136)
  • Sort databases on homepage by argument order - thanks, Tobias Kunze (#585)
  • Display metadata footer on custom SQL queries - thanks, Tobias Kunze (#589)
  • Use --platform=managed for publish cloudrun (#587)
  • Fixed bug returning non-ASCII characters in CSV (#584)
  • Fix for /foo v.s. /foo-bar bug (#601)

0.29.3 (2019-09-02)

  • Fixed implementation of CodeMirror on database page (#560)
  • Documentation typo fixes - thanks, Min ho Kim (#561)
  • Mechanism for detecting if a table has FTS enabled now works if the table name used alternative escaping mechanisms (#570) - for compatibility with a recent change to sqlite-utils.

0.29.2 (2019-07-13)

  • Bumped Uvicorn to 0.8.4, fixing a bug where the query string was not included in the server logs. (#559)
  • Fixed bug where the navigation breadcrumbs were not displayed correctly on the page for a custom query. (#558)
  • Fixed bug where custom query names containing unicode characters caused errors.

0.29.1 (2019-07-11)

  • Fixed bug with static mounts using relative paths which could lead to traversal exploits (#555) - thanks Abdussamet Kocak!
  • Datasette can now be run as a module: python -m datasette (#556) - thanks, Abdussamet Kocak!

0.29 (2019-07-07)

ASGI, new plugin hooks, facet by date and much, much more...

ASGI

ASGI is the Asynchronous Server Gateway Interface standard. I've been wanting to convert Datasette into an ASGI application for over a year - Port Datasette to ASGI #272 tracks thirteen months of intermittent development - but with Datasette 0.29 the change is finally released. This also means Datasette now runs on top of Uvicorn and no longer depends on Sanic.

I wrote about the significance of this change in Porting Datasette to ASGI, and Turtles all the way down.

The most exciting consequence of this change is that Datasette plugins can now take advantage of the ASGI standard.

New plugin hook: asgi_wrapper

The asgi_wrapper(datasette) plugin hook allows plugins to entirely wrap the Datasette ASGI application in their own ASGI middleware. (#520)

Two new plugins take advantage of this hook:

  • datasette-auth-github adds a authentication layer: users will have to sign in using their GitHub account before they can view data or interact with Datasette. You can also use it to restrict access to specific GitHub users, or to members of specified GitHub organizations or teams.
  • datasette-cors allows you to configure CORS headers for your Datasette instance. You can use this to enable JavaScript running on a whitelisted set of domains to make fetch() calls to the JSON API provided by your Datasette instance.

New plugin hook: extra_template_vars

The extra_template_vars(template, database, table, columns, view_name, request, datasette) plugin hook allows plugins to inject their own additional variables into the Datasette template context. This can be used in conjunction with custom templates to customize the Datasette interface. datasette-auth-github uses this hook to add custom HTML to the new top navigation bar (which is designed to be modified by plugins, see #540).

Secret plugin configuration options

Plugins like datasette-auth-github need a safe way to set secret configuration options. Since the default mechanism for configuring plugins exposes those settings in /-/metadata a new mechanism was needed. Secret configuration values describes how plugins can now specify that their settings should be read from a file or an environment variable:

{
    "plugins": {
        "datasette-auth-github": {
            "client_secret": {
                "$env": "GITHUB_CLIENT_SECRET"
            }
        }
    }
}

These plugin secrets can be set directly using datasette publish. See Custom metadata and plugins for details. (#538 and #543)

Facet by date

If a column contains datetime values, Datasette can now facet that column by date. (#481)

Easier custom templates for table rows

If you want to customize the display of individual table rows, you can do so using a _table.html template include that looks something like this:

{% for row in display_rows %}
    <div>
        <h2>{{ row["title"] }}</h2>
        <p>{{ row["description"] }}<lp>
        <p>Category: {{ row.display("category_id") }}</p>
    </div>
{% endfor %}

This is a backwards incompatible change. If you previously had a custom template called _rows_and_columns.html you need to rename it to _table.html.

See Custom templates for full details.

?_through= for joins through many-to-many tables

The new ?_through={json} argument to the Table view allows records to be filtered based on a many-to-many relationship. See Special table arguments for full documentation - here's an example. (#355)

This feature was added to help support facet by many-to-many, which isn't quite ready yet but will be coming in the next Datasette release.

Small changes

  • Databases published using datasette publish now open in Immutable mode. (#469)
  • ?col__date= now works for columns containing spaces
  • Automatic label detection (for deciding which column to show when linking to a foreign key) has been improved. (#485)
  • Fixed bug where pagination broke when combined with an expanded foreign key. (#489)
  • Contributors can now run pip install -e .[docs] to get all of the dependencies needed to build the documentation, including cd docs && make livehtml support.
  • Datasette's dependencies are now all specified using the ~= match operator. (#532)
  • white-space: pre-wrap now used for table creation SQL. (#505)

Full list of commits between 0.28 and 0.29.

0.28 (2019-05-19)

A salmagundi of new features!

Supporting databases that change

From the beginning of the project, Datasette has been designed with read-only databases in mind. If a database is guaranteed not to change it opens up all kinds of interesting opportunities - from taking advantage of SQLite immutable mode and HTTP caching to bundling static copies of the database directly in a Docker container. The interesting ideas in Datasette explores this idea in detail.

As my goals for the project have developed, I realized that read-only databases are no longer the right default. SQLite actually supports concurrent access very well provided only one thread attempts to write to a database at a time, and I keep encountering sensible use-cases for running Datasette on top of a database that is processing inserts and updates.

So, as-of version 0.28 Datasette no longer assumes that a database file will not change. It is now safe to point Datasette at a SQLite database which is being updated by another process.

Making this change was a lot of work - see tracking tickets #418, #419 and #420. It required new thinking around how Datasette should calculate table counts (an expensive operation against a large, changing database) and also meant reconsidering the "content hash" URLs Datasette has used in the past to optimize the performance of HTTP caches.

Datasette can still run against immutable files and gains numerous performance benefits from doing so, but this is no longer the default behaviour. Take a look at the new Performance and caching documentation section for details on how to make the most of Datasette against data that you know will be staying read-only and immutable.

Faceting improvements, and faceting plugins

Datasette Facets provide an intuitive way to quickly summarize and interact with data. Previously the only supported faceting technique was column faceting, but 0.28 introduces two powerful new capabilities: facet-by-JSON-array and the ability to define further facet types using plugins.

Facet by array (#359) is only available if your SQLite installation provides the json1 extension. Datasette will automatically detect columns that contain JSON arrays of values and offer a faceting interface against those columns - useful for modelling things like tags without needing to break them out into a new table. See Facet by JSON array for more.

The new register_facet_classes() plugin hook (#445) can be used to register additional custom facet classes. Each facet class should provide two methods: suggest() which suggests facet selections that might be appropriate for a provided SQL query, and facet_results() which executes a facet operation and returns results. Datasette's own faceting implementations have been refactored to use the same API as these plugins.

datasette publish cloudrun

Google Cloud Run is a brand new serverless hosting platform from Google, which allows you to build a Docker container which will run only when HTTP traffic is received and will shut down (and hence cost you nothing) the rest of the time. It's similar to Zeit's Now v1 Docker hosting platform which sadly is no longer accepting signups from new users.

The new datasette publish cloudrun command was contributed by Romain Primet (#434) and publishes selected databases to a new Datasette instance running on Google Cloud Run.

See Publishing to Google Cloud Run for full documentation.

register_output_renderer plugins

Russ Garrett implemented a new Datasette plugin hook called register_output_renderer (#441) which allows plugins to create additional output renderers in addition to Datasette's default .json and .csv.

Russ's in-development datasette-geo plugin includes an example of this hook being used to output .geojson automatically converted from SpatiaLite.

Medium changes

  • Datasette now conforms to the Black coding style (#449) - and has a unit test to enforce this in the future
  • New Special table arguments:
    • ?columnname__in=value1,value2,value3 filter for executing SQL IN queries against a table, see Table arguments (#433)
    • ?columnname__date=yyyy-mm-dd filter which returns rows where the spoecified datetime column falls on the specified date (583b22a)
    • ?tags__arraycontains=tag filter which acts against a JSON array contained in a column (78e45ea)
    • ?_where=sql-fragment filter for the table view (#429)
    • ?_fts_table=mytable and ?_fts_pk=mycolumn query string options can be used to specify which FTS table to use for a search query - see Configuring full-text search for a table or view (#428)
  • You can now pass the same table filter multiple times - for example, ?content__not=world&content__not=hello will return all rows where the content column is neither hello or world (#288)
  • You can now specify about and about_url metadata (in addition to source and license) linking to further information about a project - see Source, license and about
  • New ?_trace=1 parameter now adds debug information showing every SQL query that was executed while constructing the page (#435)
  • datasette inspect now just calculates table counts, and does not introspect other database metadata (#462)
  • Removed /-/inspect page entirely - this will be replaced by something similar in the future, see #465
  • Datasette can now run against an in-memory SQLite database. You can do this by starting it without passing any files or by using the new --memory option to datasette serve. This can be useful for experimenting with SQLite queries that do not access any data, such as SELECT 1+1 or SELECT sqlite_version().

Small changes

  • We now show the size of the database file next to the download link (#172)
  • New /-/databases introspection page shows currently connected databases (#470)
  • Binary data is no longer displayed on the table and row pages (#442 - thanks, Russ Garrett)
  • New show/hide SQL links on custom query pages (#415)
  • The extra_body_script plugin hook now accepts an optional view_name argument (#443 - thanks, Russ Garrett)
  • Bumped Jinja2 dependency to 2.10.1 (#426)
  • All table filters are now documented, and documentation is enforced via unit tests (2c19a27)
  • New project guideline: master should stay shippable at all times! (31f36e1)
  • Fixed a bug where sqlite_timelimit() occasionally failed to clean up after itself (bac4e01)
  • We no longer load additional plugins when executing pytest (#438)
  • Homepage now links to database views if there are less than five tables in a database (#373)
  • The --cors option is now respected by error pages (#453)
  • datasette publish heroku now uses the --include-vcs-ignore option, which means it works under Travis CI (#407)
  • datasette publish heroku now publishes using Python 3.6.8 (666c374)
  • Renamed datasette publish now to datasette publish nowv1 (#472)
  • datasette publish nowv1 now accepts multiple --alias parameters (09ef305)
  • Removed the datasette skeleton command (#476)
  • The documentation on how to build the documentation now recommends sphinx-autobuild

0.27.1 (2019-05-09)

  • Tiny bugfix release: don't install tests/ in the wrong place. Thanks, Veit Heller.

0.27 (2019-01-31)

0.26.1 (2019-01-10)

  • /-/versions now includes SQLite compile_options (#396)
  • datasetteproject/datasette Docker image now uses SQLite 3.26.0 (#397)
  • Cleaned up some deprecation warnings under Python 3.7

0.26 (2019-01-02)

  • datasette serve --reload now restarts Datasette if a database file changes on disk.
  • datasette publish now now takes an optional --alias mysite.now.sh argument. This will attempt to set an alias after the deploy completes.
  • Fixed a bug where the advanced CSV export form failed to include the currently selected filters (#393)

0.25.2 (2018-12-16)

0.25.1 (2018-11-04)

Documentation improvements plus a fix for publishing to Zeit Now.

  • datasette publish now now uses Zeit's v1 platform, to work around the new 100MB image limit. Thanks, @slygent - closes #366.

0.25 (2018-09-19)

New plugin hooks, improved database view support and an easier way to use more recent versions of SQLite.

  • New publish_subcommand plugin hook. A plugin can now add additional datasette publish publishers in addition to the default now and heroku, both of which have been refactored into default plugins. publish_subcommand documentation. Closes #349
  • New render_cell plugin hook. Plugins can now customize how values are displayed in the HTML tables produced by Datasette's browseable interface. datasette-json-html and datasette-render-images are two new plugins that use this hook. render_cell documentation. Closes #352
  • New extra_body_script plugin hook, enabling plugins to provide additional JavaScript that should be added to the page footer. extra_body_script documentation.
  • extra_css_urls and extra_js_urls hooks now take additional optional parameters, allowing them to be more selective about which pages they apply to. Documentation.
  • You can now use the sortable_columns metadata setting to explicitly enable sort-by-column in the interface for database views, as well as for specific tables.
  • The new fts_table and fts_pk metadata settings can now be used to explicitly configure full-text search for a table or a view, even if that table is not directly coupled to the SQLite FTS feature in the database schema itself.
  • Datasette will now use pysqlite3 in place of the standard library sqlite3 module if it has been installed in the current environment. This makes it much easier to run Datasette against a more recent version of SQLite, including the just-released SQLite 3.25.0 which adds window function support. More details on how to use this in #360
  • New mechanism that allows plugin configuration options to be set using metadata.json.

0.24 (2018-07-23)

A number of small new features:

  • datasette publish heroku now supports --extra-options, fixes #334
  • Custom error message if SpatiaLite is needed for specified database, closes #331
  • New config option: truncate_cells_html for truncating long cell values in HTML view - closes #330
  • Documentation for datasette publish and datasette package, closes #337
  • Fixed compatibility with Python 3.7
  • datasette publish heroku now supports app names via the -n option, which can also be used to overwrite an existing application [Russ Garrett]
  • Title and description metadata can now be set for canned SQL queries, closes #342
  • New force_https_on config option, fixes https:// API URLs when deploying to Zeit Now - closes #333
  • ?_json_infinity=1 query string argument for handling Infinity/-Infinity values in JSON, closes #332
  • URLs displayed in the results of custom SQL queries are now URLified, closes #298

0.23.2 (2018-07-07)

Minor bugfix and documentation release.

0.23.1 (2018-06-21)

Minor bugfix release.

  • Correctly display empty strings in HTML table, closes #314
  • Allow "." in database filenames, closes #302
  • 404s ending in slash redirect to remove that slash, closes #309
  • Fixed incorrect display of compound primary keys with foreign key references. Closes #319
  • Docs + example of canned SQL query using || concatenation. Closes #321
  • Correctly display facets with value of 0 - closes #318
  • Default 'expand labels' to checked in CSV advanced export

0.23 (2018-06-18)

This release features CSV export, improved options for foreign key expansions, new configuration settings and improved support for SpatiaLite.

See datasette/compare/0.22.1...0.23 for a full list of commits added since the last release.

CSV export

Any Datasette table, view or custom SQL query can now be exported as CSV.

_images/advanced_export.png

Check out the CSV export documentation for more details, or try the feature out on https://fivethirtyeight.datasettes.com/fivethirtyeight/bechdel%2Fmovies

If your table has more than max_returned_rows (default 1,000) Datasette provides the option to stream all rows. This option takes advantage of async Python and Datasette's efficient pagination to iterate through the entire matching result set and stream it back as a downloadable CSV file.

Foreign key expansions

When Datasette detects a foreign key reference it attempts to resolve a label for that reference (automatically or using the Specifying the label column for a table metadata option) so it can display a link to the associated row.

This expansion is now also available for JSON and CSV representations of the table, using the new _labels=on query string option. See Expanding foreign key references for more details.

New configuration settings

Datasette's Settings now also supports boolean settings. A number of new configuration options have been added:

  • num_sql_threads - the number of threads used to execute SQLite queries. Defaults to 3.
  • allow_facet - enable or disable custom Facets using the _facet= parameter. Defaults to on.
  • suggest_facets - should Datasette suggest facets? Defaults to on.
  • allow_download - should users be allowed to download the entire SQLite database? Defaults to on.
  • allow_sql - should users be allowed to execute custom SQL queries? Defaults to on.
  • default_cache_ttl - Default HTTP caching max-age header in seconds. Defaults to 365 days - caching can be disabled entirely by settings this to 0.
  • cache_size_kb - Set the amount of memory SQLite uses for its per-connection cache, in KB.
  • allow_csv_stream - allow users to stream entire result sets as a single CSV file. Defaults to on.
  • max_csv_mb - maximum size of a returned CSV file in MB. Defaults to 100MB, set to 0 to disable this limit.

Control HTTP caching with ?_ttl=

You can now customize the HTTP max-age header that is sent on a per-URL basis, using the new ?_ttl= query string parameter.

You can set this to any value in seconds, or you can set it to 0 to disable HTTP caching entirely.

Consider for example this query which returns a randomly selected member of the Avengers:

select * from [avengers/avengers] order by random() limit 1

If you hit the following page repeatedly you will get the same result, due to HTTP caching:

/fivethirtyeight?sql=select+*+from+%5Bavengers%2Favengers%5D+order+by+random%28%29+limit+1

By adding ?_ttl=0 to the zero you can ensure the page will not be cached and get back a different super hero every time:

/fivethirtyeight?sql=select+*+from+%5Bavengers%2Favengers%5D+order+by+random%28%29+limit+1&_ttl=0

Improved support for SpatiaLite

The SpatiaLite module for SQLite adds robust geospatial features to the database.

Getting SpatiaLite working can be tricky, especially if you want to use the most recent alpha version (with support for K-nearest neighbor).

Datasette now includes extensive documentation on SpatiaLite, and thanks to Ravi Kotecha our GitHub repo includes a Dockerfile that can build the latest SpatiaLite and configure it for use with Datasette.

The datasette publish and datasette package commands now accept a new --spatialite argument which causes them to install and configure SpatiaLite as part of the container they deploy.

latest.datasette.io

Every commit to Datasette master is now automatically deployed by Travis CI to https://latest.datasette.io/ - ensuring there is always a live demo of the latest version of the software.

The demo uses the fixtures from our unit tests, ensuring it demonstrates the same range of functionality that is covered by the tests.

You can see how the deployment mechanism works in our .travis.yml file.

Miscellaneous

  • Got JSON data in one of your columns? Use the new ?_json=COLNAME argument to tell Datasette to return that JSON value directly rather than encoding it as a string.
  • If you just want an array of the first value of each row, use the new ?_shape=arrayfirst option - example.

0.22.1 (2018-05-23)

Bugfix release, plus we now use versioneer for our version numbers.

  • Faceting no longer breaks pagination, fixes #282

  • Add __version_info__ derived from __version__ [Robert Gieseke]

    This might be tuple of more than two values (major and minor version) if commits have been made after a release.

  • Add version number support with Versioneer. [Robert Gieseke]

    Versioneer Licence: Public Domain (CC0-1.0)

    Closes #273

  • Refactor inspect logic [Russ Garrett]

0.22 (2018-05-20)

The big new feature in this release is Facets. Datasette can now apply faceted browse to any column in any table. It will also suggest possible facets. See the Datasette Facets announcement post for more details.

In addition to the work on facets:

  • Added docs for introspection endpoints

  • New --config option, added --help-config, closes #274

    Removed the --page_size= argument to datasette serve in favour of:

    datasette serve --config default_page_size:50 mydb.db
    

    Added new help section:

    $ datasette --help-config
    Config options:
      default_page_size            Default page size for the table view
                                   (default=100)
      max_returned_rows            Maximum rows that can be returned from a table
                                   or custom query (default=1000)
      sql_time_limit_ms            Time limit for a SQL query in milliseconds
                                   (default=1000)
      default_facet_size           Number of values to return for requested facets
                                   (default=30)
      facet_time_limit_ms          Time limit for calculating a requested facet
                                   (default=200)
      facet_suggest_time_limit_ms  Time limit for calculating a suggested facet
                                   (default=50)
    
  • Only apply responsive table styles to .rows-and-column

    Otherwise they interfere with tables in the description, e.g. on https://fivethirtyeight.datasettes.com/fivethirtyeight/nba-elo%2Fnbaallelo

  • Refactored views into new views/ modules, refs #256

  • Documentation for SQLite full-text search support, closes #253

  • /-/versions now includes SQLite fts_versions, closes #252

0.21 (2018-05-05)

New JSON _shape= options, the ability to set table _size= and a mechanism for searching within specific columns.

  • Default tests to using a longer timelimit

    Every now and then a test will fail in Travis CI on Python 3.5 because it hit the default 20ms SQL time limit.

    Test fixtures now default to a 200ms time limit, and we only use the 20ms time limit for the specific test that tests query interruption. This should make our tests on Python 3.5 in Travis much more stable.

  • Support _search_COLUMN=text searches, closes #237

  • Show version on /-/plugins page, closes #248

  • ?_size=max option, closes #249

  • Added /-/versions and /-/versions.json, closes #244

    Sample output:

    {
      "python": {
        "version": "3.6.3",
        "full": "3.6.3 (default, Oct  4 2017, 06:09:38) \n[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.37)]"
      },
      "datasette": {
        "version": "0.20"
      },
      "sqlite": {
        "version": "3.23.1",
        "extensions": {
          "json1": null,
          "spatialite": "4.3.0a"
        }
      }
    }
    
  • Renamed ?_sql_time_limit_ms= to ?_timelimit, closes #242

  • New ?_shape=array option + tweaks to _shape, closes #245

    • Default is now ?_shape=arrays (renamed from lists)
    • New ?_shape=array returns an array of objects as the root object
    • Changed ?_shape=object to return the object as the root
    • Updated docs
  • FTS tables now detected by inspect(), closes #240

  • New ?_size=XXX query string parameter for table view, closes #229

    Also added documentation for all of the _special arguments.

    Plus deleted some duplicate logic implementing _group_count.

  • If max_returned_rows==page_size, increment max_returned_rows - fixes #230

  • New hidden: True option for table metadata, closes #239

  • Hide idx_* tables if spatialite detected, closes #228

  • Added class=rows-and-columns to custom query results table

  • Added CSS class rows-and-columns to main table

  • label_column option in metadata.json - closes #234

0.20 (2018-04-20)

Mostly new work on the Plugins mechanism: plugins can now bundle static assets and custom templates, and datasette publish has a new --install=name-of-plugin option.

  • Add col-X classes to HTML table on custom query page

  • Fixed out-dated template in documentation

  • Plugins can now bundle custom templates, #224

  • Added /-/metadata /-/plugins /-/inspect, #225

  • Documentation for --install option, refs #223

  • Datasette publish/package --install option, #223

  • Fix for plugins in Python 3.5, #222

  • New plugin hooks: extra_css_urls() and extra_js_urls(), #214

  • /-/static-plugins/PLUGIN_NAME/ now serves static/ from plugins

  • <th> now gets class="col-X" - plus added col-X documentation

  • Use to_css_class for table cell column classes

    This ensures that columns with spaces in the name will still generate usable CSS class names. Refs #209

  • Add column name classes to <td>s, make PK bold [Russ Garrett]

  • Don't duplicate simple primary keys in the link column [Russ Garrett]

    When there's a simple (single-column) primary key, it looks weird to duplicate it in the link column.

    This change removes the second PK column and treats the link column as if it were the PK column from a header/sorting perspective.

  • Correct escaping for HTML display of row links [Russ Garrett]

  • Longer time limit for test_paginate_compound_keys

    It was failing intermittently in Travis - see #209

  • Use application/octet-stream for downloadable databases

  • Updated PyPI classifiers

  • Updated PyPI link to pypi.org

0.19 (2018-04-16)

This is the first preview of the new Datasette plugins mechanism. Only two plugin hooks are available so far - for custom SQL functions and custom template filters. There's plenty more to come - read the documentation and get involved in the tracking ticket if you have feedback on the direction so far.

  • Fix for _sort_desc=sortable_with_nulls test, refs #216

  • Fixed #216 - paginate correctly when sorting by nullable column

  • Initial documentation for plugins, closes #213

    https://docs.datasette.io/en/stable/plugins.html

  • New --plugins-dir=plugins/ option (#212)

    New option causing Datasette to load and evaluate all of the Python files in the specified directory and register any plugins that are defined in those files.

    This new option is available for the following commands:

    datasette serve mydb.db --plugins-dir=plugins/
    datasette publish now/heroku mydb.db --plugins-dir=plugins/
    datasette package mydb.db --plugins-dir=plugins/
    
  • Start of the plugin system, based on pluggy (#210)

    Uses https://pluggy.readthedocs.io/ originally created for the py.test project

    We're starting with two plugin hooks:

    prepare_connection(conn)

    This is called when a new SQLite connection is created. It can be used to register custom SQL functions.

    prepare_jinja2_environment(env)

    This is called with the Jinja2 environment. It can be used to register custom template tags and filters.

    An example plugin which uses these two hooks can be found at https://github.com/simonw/datasette-plugin-demos or installed using pip install datasette-plugin-demos

    Refs #14

  • Return HTTP 405 on InvalidUsage rather than 500. [Russ Garrett]

    This also stops it filling up the logs. This happens for HEAD requests at the moment - which perhaps should be handled better, but that's a different issue.

0.18 (2018-04-14)

This release introduces support for units, contributed by Russ Garrett (#203). You can now optionally specify the units for specific columns using metadata.json. Once specified, units will be displayed in the HTML view of your table. They also become available for use in filters - if a column is configured with a unit of distance, you can request all rows where that column is less than 50 meters or more than 20 feet for example.

  • Link foreign keys which don't have labels. [Russ Garrett]

    This renders unlabeled FKs as simple links.

    Also includes bonus fixes for two minor issues:

    • In foreign key link hrefs the primary key was escaped using HTML escaping rather than URL escaping. This broke some non-integer PKs.
    • Print tracebacks to console when handling 500 errors.
  • Fix SQLite error when loading rows with no incoming FKs. [Russ Garrett]

    This fixes an error caused by an invalid query when loading incoming FKs.

    The error was ignored due to async but it still got printed to the console.

  • Allow custom units to be registered with Pint. [Russ Garrett]

  • Support units in filters. [Russ Garrett]

  • Tidy up units support. [Russ Garrett]

    • Add units to exported JSON
    • Units key in metadata skeleton
    • Docs
  • Initial units support. [Russ Garrett]

    Add support for specifying units for a column in metadata.json and rendering them on display using pint

0.17 (2018-04-13)

  • Release 0.17 to fix issues with PyPI

0.16 (2018-04-13)

  • Better mechanism for handling errors; 404s for missing table/database

    New error mechanism closes #193

    404s for missing tables/databases closes #184

  • long_description in markdown for the new PyPI

  • Hide SpatiaLite system tables. [Russ Garrett]

  • Allow explain select / explain query plan select #201

  • Datasette inspect now finds primary_keys #195

  • Ability to sort using form fields (for mobile portrait mode) #199

    We now display sort options as a select box plus a descending checkbox, which means you can apply sort orders even in portrait mode on a mobile phone where the column headers are hidden.

0.15 (2018-04-09)

The biggest new feature in this release is the ability to sort by column. On the table page the column headers can now be clicked to apply sort (or descending sort), or you can specify ?_sort=column or ?_sort_desc=column directly in the URL.

  • table_rows => table_rows_count, filtered_table_rows => filtered_table_rows_count

    Renamed properties. Closes #194

  • New sortable_columns option in metadata.json to control sort options.

    You can now explicitly set which columns in a table can be used for sorting using the _sort and _sort_desc arguments using metadata.json:

    {
        "databases": {
            "database1": {
                "tables": {
                    "example_table": {
                        "sortable_columns": [
                            "height",
                            "weight"
                        ]
                    }
                }
            }
        }
    }
    

    Refs #189

  • Column headers now link to sort/desc sort - refs #189

  • _sort and _sort_desc parameters for table views

    Allows for paginated sorted results based on a specified column.

    Refs #189

  • Total row count now correct even if _next applied

  • Use .custom_sql() for _group_count implementation (refs #150)

  • Make HTML title more readable in query template (#180) [Ryan Pitts]

  • New ?_shape=objects/object/lists param for JSON API (#192)

    New _shape= parameter replacing old .jsono extension

    Now instead of this:

    /database/table.jsono
    

    We use the _shape parameter like this:

    /database/table.json?_shape=objects
    

    Also introduced a new _shape called object which looks like this:

    /database/table.json?_shape=object
    

    Returning an object for the rows key:

    ...
    "rows": {
        "pk1": {
            ...
        },
        "pk2": {
            ...
        }
    }
    

    Refs #122

  • Utility for writing test database fixtures to a .db file

    python tests/fixtures.py /tmp/hello.db

    This is useful for making a SQLite database of the test fixtures for interactive exploration.

  • Compound primary key _next= now plays well with extra filters

    Closes #190

  • Fixed bug with keyset pagination over compound primary keys

    Refs #190

  • Database/Table views inherit source/license/source_url/license_url metadata

    If you set the source_url/license_url/source/license fields in your root metadata those values will now be inherited all the way down to the database and table templates.

    The title/description are NOT inherited.

    Also added unit tests for the HTML generated by the metadata.

    Refs #185

  • Add metadata, if it exists, to heroku temp dir (#178) [Tony Hirst]

  • Initial documentation for pagination

  • Broke up test_app into test_api and test_html

  • Fixed bug with .json path regular expression

    I had a table called geojson and it caused an exception because the regex was matching .json and not \.json

  • Deploy to Heroku with Python 3.6.3

0.14 (2017-12-09)

The theme of this release is customization: Datasette now allows every aspect of its presentation to be customized either using additional CSS or by providing entirely new templates.

Datasette's metadata.json format has also been expanded, to allow per-database and per-table metadata. A new datasette skeleton command can be used to generate a skeleton JSON file ready to be filled in with per-database and per-table details.

The metadata.json file can also be used to define canned queries, as a more powerful alternative to SQL views.

  • extra_css_urls/extra_js_urls in metadata

    A mechanism in the metadata.json format for adding custom CSS and JS urls.

    Create a metadata.json file that looks like this:

    {
        "extra_css_urls": [
            "https://simonwillison.net/static/css/all.bf8cd891642c.css"
        ],
        "extra_js_urls": [
            "https://code.jquery.com/jquery-3.2.1.slim.min.js"
        ]
    }
    

    Then start datasette like this:

    datasette mydb.db --metadata=metadata.json
    

    The CSS and JavaScript files will be linked in the <head> of every page.

    You can also specify a SRI (subresource integrity hash) for these assets:

    {
        "extra_css_urls": [
            {
                "url": "https://simonwillison.net/static/css/all.bf8cd891642c.css",
                "sri": "sha384-9qIZekWUyjCyDIf2YK1FRoKiPJq4PHt6tp/ulnuuyRBvazd0hG7pWbE99zvwSznI"
            }
        ],
        "extra_js_urls": [
            {
                "url": "https://code.jquery.com/jquery-3.2.1.slim.min.js",
                "sri": "sha256-k2WSCIexGzOj3Euiig+TlR8gA0EmPjuc79OEeY5L45g="
            }
        ]
    }
    

    Modern browsers will only execute the stylesheet or JavaScript if the SRI hash matches the content served. You can generate hashes using https://www.srihash.org/

  • Auto-link column values that look like URLs (#153)

  • CSS styling hooks as classes on the body (#153)

    Every template now gets CSS classes in the body designed to support custom styling.

    The index template (the top level page at /) gets this:

    <body class="index">
    

    The database template (/dbname/) gets this:

    <body class="db db-dbname">
    

    The table template (/dbname/tablename) gets:

    <body class="table db-dbname table-tablename">
    

    The row template (/dbname/tablename/rowid) gets:

    <body class="row db-dbname table-tablename">
    

    The db-x and table-x classes use the database or table names themselves IF they are valid CSS identifiers. If they aren't, we strip any invalid characters out and append a 6 character md5 digest of the original name, in order to ensure that multiple tables which resolve to the same stripped character version still have different CSS classes.

    Some examples (extracted from the unit tests):

    "simple" => "simple"
    "MixedCase" => "MixedCase"
    "-no-leading-hyphens" => "no-leading-hyphens-65bea6"
    "_no-leading-underscores" => "no-leading-underscores-b921bc"
    "no spaces" => "no-spaces-7088d7"
    "-" => "336d5e"
    "no $ characters" => "no--characters-59e024"
    
  • datasette --template-dir=mytemplates/ argument

    You can now pass an additional argument specifying a directory to look for custom templates in.

    Datasette will fall back on the default templates if a template is not found in that directory.

  • Ability to over-ride templates for individual tables/databases.

    It is now possible to over-ride templates on a per-database / per-row or per- table basis.

    When you access e.g. /mydatabase/mytable Datasette will look for the following:

    - table-mydatabase-mytable.html
    - table.html
    

    If you provided a --template-dir argument to datasette serve it will look in that directory first.

    The lookup rules are as follows:

    Index page (/):
        index.html
    
    Database page (/mydatabase):
        database-mydatabase.html
        database.html
    
    Table page (/mydatabase/mytable):
        table-mydatabase-mytable.html
        table.html
    
    Row page (/mydatabase/mytable/id):
        row-mydatabase-mytable.html
        row.html
    

    If a table name has spaces or other unexpected characters in it, the template filename will follow the same rules as our custom <body> CSS classes - for example, a table called "Food Trucks" will attempt to load the following templates:

    table-mydatabase-Food-Trucks-399138.html
    table.html
    

    It is possible to extend the default templates using Jinja template inheritance. If you want to customize EVERY row template with some additional content you can do so by creating a row.html template like this:

    {% extends "default:row.html" %}
    
    {% block content %}
    <h1>EXTRA HTML AT THE TOP OF THE CONTENT BLOCK</h1>
    <p>This line renders the original block:</p>
    {{ super() }}
    {% endblock %}
    
  • --static option for datasette serve (#160)

    You can now tell Datasette to serve static files from a specific location at a specific mountpoint.

    For example:

    datasette serve mydb.db --static extra-css:/tmp/static/css
    

    Now if you visit this URL:

    http://localhost:8001/extra-css/blah.css
    

    The following file will be served:

    /tmp/static/css/blah.css
    
  • Canned query support.

    Named canned queries can now be defined in metadata.json like this:

    {
        "databases": {
            "timezones": {
                "queries": {
                    "timezone_for_point": "select tzid from timezones ..."
                }
            }
        }
    }
    

    These will be shown in a new "Queries" section beneath "Views" on the database page.

  • New datasette skeleton command for generating metadata.json (#164)

  • metadata.json support for per-table/per-database metadata (#165)

    Also added support for descriptions and HTML descriptions.

    Here's an example metadata.json file illustrating custom per-database and per- table metadata:

    {
        "title": "Overall datasette title",
        "description_html": "This is a <em>description with HTML</em>.",
        "databases": {
            "db1": {
                "title": "First database",
                "description": "This is a string description & has no HTML",
                "license_url": "http://example.com/",
            "license": "The example license",
                "queries": {
                  "canned_query": "select * from table1 limit 3;"
                },
                "tables": {
                    "table1": {
                        "title": "Custom title for table1",
                        "description": "Tables can have descriptions too",
                        "source": "This has a custom source",
                        "source_url": "http://example.com/"
                    }
                }
            }
        }
    }
    
  • Renamed datasette build command to datasette inspect (#130)

  • Upgrade to Sanic 0.7.0 (#168)

    https://github.com/channelcat/sanic/releases/tag/0.7.0

  • Package and publish commands now accept --static and --template-dir

    Example usage:

    datasette package --static css:extra-css/ --static js:extra-js/ \
      sf-trees.db --template-dir templates/ --tag sf-trees --branch master
    

    This creates a local Docker image that includes copies of the templates/, extra-css/ and extra-js/ directories. You can then run it like this:

    docker run -p 8001:8001 sf-trees
    

    For publishing to Zeit now:

    datasette publish now --static css:extra-css/ --static js:extra-js/ \
      sf-trees.db --template-dir templates/ --name sf-trees --branch master
    
  • HTML comment showing which templates were considered for a page (#171)

0.13 (2017-11-24)

  • Search now applies to current filters.

    Combined search into the same form as filters.

    Closes #133

  • Much tidier design for table view header.

    Closes #147

  • Added ?column__not=blah filter.

    Closes #148

  • Row page now resolves foreign keys.

    Closes #132

  • Further tweaks to select/input filter styling.

    Refs #86 - thanks for the help, @natbat!

  • Show linked foreign key in table cells.

  • Added UI for editing table filters.

    Refs #86

  • Hide FTS-created tables on index pages.

    Closes #129

  • Add publish to heroku support [Jacob Kaplan-Moss]

    datasette publish heroku mydb.db

    Pull request #104

  • Initial implementation of ?_group_count=column.

    URL shortcut for counting rows grouped by one or more columns.

    ?_group_count=column1&_group_count=column2 works as well.

    SQL generated looks like this:

    select "qSpecies", count(*) as "count"
    from Street_Tree_List
    group by "qSpecies"
    order by "count" desc limit 100
    

    Or for two columns like this:

    select "qSpecies", "qSiteInfo", count(*) as "count"
    from Street_Tree_List
    group by "qSpecies", "qSiteInfo"
    order by "count" desc limit 100
    

    Refs #44

  • Added --build=master option to datasette publish and package.

    The datasette publish and datasette package commands both now accept an optional --build argument. If provided, this can be used to specify a branch published to GitHub that should be built into the container.

    This makes it easier to test code that has not yet been officially released to PyPI, e.g.:

    datasette publish now mydb.db --branch=master
    
  • Implemented ?_search=XXX + UI if a FTS table is detected.

    Closes #131

  • Added datasette --version support.

  • Table views now show expanded foreign key references, if possible.

    If a table has foreign key columns, and those foreign key tables have label_columns, the TableView will now query those other tables for the corresponding values and display those values as links in the corresponding table cells.

    label_columns are currently detected by the inspect() function, which looks for any table that has just two columns - an ID column and one other - and sets the label_column to be that second non-ID column.

  • Don't prevent tabbing to "Run SQL" button (#117) [Robert Gieseke]

    See comment in #115

  • Add keyboard shortcut to execute SQL query (#115) [Robert Gieseke]

  • Allow --load-extension to be set via environment variable.

  • Add support for ?field__isnull=1 (#107) [Ray N]

  • Add spatialite, switch to debian and local build (#114) [Ariel Núñez]

  • Added --load-extension argument to datasette serve.

    Allows loading of SQLite extensions. Refs #110.

0.12 (2017-11-16)

  • Added __version__, now displayed as tooltip in page footer (#108).

  • Added initial docs, including a changelog (#99).

  • Turned on auto-escaping in Jinja.

  • Added a UI for editing named parameters (#96).

    You can now construct a custom SQL statement using SQLite named parameters (e.g. :name) and datasette will display form fields for editing those parameters. Here’s an example which lets you see the most popular names for dogs of different species registered through various dog registration schemes in Australia.

  • Pin to specific Jinja version. (#100).

  • Default to 127.0.0.1 not 0.0.0.0. (#98).

  • Added extra metadata options to publish and package commands. (#92).

    You can now run these commands like so:

    datasette now publish mydb.db \
        --title="My Title" \
        --source="Source" \
        --source_url="http://www.example.com/" \
        --license="CC0" \
        --license_url="https://creativecommons.org/publicdomain/zero/1.0/"
    

    This will write those values into the metadata.json that is packaged with the app. If you also pass --metadata=metadata.json that file will be updated with the extra values before being written into the Docker image.

  • Added production-ready Dockerfile (#94) [Andrew Cutler]

  • New ?_sql_time_limit_ms=10 argument to database and table page (#95)

  • SQL syntax highlighting with Codemirror (#89) [Tom Dyson]

0.11 (2017-11-14)

  • Added datasette publish now --force option.

    This calls now with --force - useful as it means you get a fresh copy of datasette even if Now has already cached that docker layer.

  • Enable --cors by default when running in a container.

0.10 (2017-11-14)

  • Fixed #83 - 500 error on individual row pages.

  • Stop using sqlite WITH RECURSIVE in our tests.

    The version of Python 3 running in Travis CI doesn't support this.

0.9 (2017-11-13)

  • Added --sql_time_limit_ms and --extra-options.

    The serve command now accepts --sql_time_limit_ms for customizing the SQL time limit.

    The publish and package commands now accept --extra-options which can be used to specify additional options to be passed to the datasite serve command when it executes inside the resulting Docker containers.

0.8 (2017-11-13)

  • V0.8 - added PyPI metadata, ready to ship.

  • Implemented offset/limit pagination for views (#70).

  • Improved pagination. (#78)

  • Limit on max rows returned, controlled by --max_returned_rows option. (#69)

    If someone executes 'select * from table' against a table with a million rows in it, we could run into problems: just serializing that much data as JSON is likely to lock up the server.

    Solution: we now have a hard limit on the maximum number of rows that can be returned by a query. If that limit is exceeded, the server will return a "truncated": true field in the JSON.

    This limit can be optionally controlled by the new --max_returned_rows option. Setting that option to 0 disables the limit entirely.