datasette 0.54

on Python PyPI

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)