kopia lustrzana https://github.com/simonw/datasette
1151 wiersze
41 KiB
ReStructuredText
1151 wiersze
41 KiB
ReStructuredText
.. _plugins:
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Plugins
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=======
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Datasette's plugin system allows additional features to be implemented as Python
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code (or front-end JavaScript) which can be wrapped up in a separate Python
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package. The underlying mechanism uses `pluggy <https://pluggy.readthedocs.io/>`_.
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See :ref:`ecosystem_plugins` for a list of existing plugins, or take a look at the
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`datasette-plugin <https://github.com/topics/datasette-plugin>`__ topic on GitHub.
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Things you can do with plugins include:
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* Add visualizations to Datasette, for example
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`datasette-cluster-map <https://github.com/simonw/datasette-cluster-map>`__ and
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`datasette-vega <https://github.com/simonw/datasette-vega>`__.
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* Make new custom SQL functions available for use within Datasette, for example
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`datasette-haversine <https://github.com/simonw/datasette-haversine>`__ and
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`datasette-jellyfish <https://github.com/simonw/datasette-jellyfish>`__.
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* Define custom output formats with custom extensions, for example `datasette-atom <https://github.com/simonw/datasette-atom>`__ and
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`datasette-ics <https://github.com/simonw/datasette-ics>`__.
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* Add template functions that can be called within your Jinja custom templates,
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for example `datasette-render-markdown <https://github.com/simonw/datasette-render-markdown#markdown-in-templates>`__.
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* Customize how database values are rendered in the Datasette interface, for example
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`datasette-render-binary <https://github.com/simonw/datasette-render-binary>`__ and
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`datasette-pretty-json <https://github.com/simonw/datasette-pretty-json>`__.
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* Customize how Datasette's authentication and permissions systems work, for example `datasette-auth-tokens <https://github.com/simonw/datasette-auth-tokens>`__ and
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`datasette-permissions-sql <https://github.com/simonw/datasette-permissions-sql>`__.
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.. _plugins_installing:
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Installing plugins
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------------------
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If a plugin has been packaged for distribution using setuptools you can use
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the plugin by installing it alongside Datasette in the same virtual
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environment or Docker container.
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You can also define one-off per-project plugins by saving them as
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``plugin_name.py`` functions in a ``plugins/`` folder and then passing that
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folder to ``datasette serve``.
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The ``datasette publish`` and ``datasette package`` commands both take an
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optional ``--install`` argument. You can use this one or more times to tell
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Datasette to ``pip install`` specific plugins as part of the process. You can
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use the name of a package on PyPI or any of the other valid arguments to ``pip
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install`` such as a URL to a ``.zip`` file::
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datasette publish cloudrun mydb.db \
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--install=datasette-plugin-demos \
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--install=https://url-to-my-package.zip
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.. _plugins_writing_one_off:
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Writing one-off plugins
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-----------------------
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The easiest way to write a plugin is to create a ``my_plugin.py`` file and
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drop it into your ``plugins/`` directory. Here is an example plugin, which
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adds a new custom SQL function called ``hello_world()`` which takes no
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arguments and returns the string ``Hello world!``.
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.. code-block:: python
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from datasette import hookimpl
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@hookimpl
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def prepare_connection(conn):
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conn.create_function('hello_world', 0, lambda: 'Hello world!')
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If you save this in ``plugins/my_plugin.py`` you can then start Datasette like
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this::
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datasette serve mydb.db --plugins-dir=plugins/
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Now you can navigate to http://localhost:8001/mydb and run this SQL::
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select hello_world();
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To see the output of your plugin.
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.. _plugins_installed:
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Seeing what plugins are installed
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---------------------------------
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You can see a list of installed plugins by navigating to the ``/-/plugins`` page of your Datasette instance - for example: https://fivethirtyeight.datasettes.com/-/plugins
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You can also use the ``datasette plugins`` command::
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$ datasette plugins
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[
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{
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"name": "datasette_json_html",
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"static": false,
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"templates": false,
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"version": "0.4.0"
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}
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]
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If you run ``datasette plugins --all`` it will include default plugins that ship as part of Datasette::
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$ datasette plugins --all
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[
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{
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"name": "datasette.sql_functions",
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"static": false,
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"templates": false,
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"version": null
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},
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{
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"name": "datasette.publish.cloudrun",
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"static": false,
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"templates": false,
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"version": null
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},
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{
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"name": "datasette.facets",
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"static": false,
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"templates": false,
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"version": null
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},
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{
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"name": "datasette.publish.heroku",
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"static": false,
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"templates": false,
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"version": null
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}
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]
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You can add the ``--plugins-dir=`` option to include any plugins found in that directory.
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Packaging a plugin
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------------------
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Plugins can be packaged using Python setuptools. You can see an example of a
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packaged plugin at https://github.com/simonw/datasette-plugin-demos
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The example consists of two files: a ``setup.py`` file that defines the plugin:
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.. code-block:: python
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from setuptools import setup
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VERSION = '0.1'
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setup(
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name='datasette-plugin-demos',
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description='Examples of plugins for Datasette',
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author='Simon Willison',
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url='https://github.com/simonw/datasette-plugin-demos',
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license='Apache License, Version 2.0',
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version=VERSION,
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py_modules=['datasette_plugin_demos'],
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entry_points={
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'datasette': [
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'plugin_demos = datasette_plugin_demos'
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]
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},
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install_requires=['datasette']
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)
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And a Python module file, ``datasette_plugin_demos.py``, that implements the
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plugin:
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.. code-block:: python
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from datasette import hookimpl
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import random
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@hookimpl
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def prepare_jinja2_environment(env):
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env.filters['uppercase'] = lambda u: u.upper()
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@hookimpl
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def prepare_connection(conn):
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conn.create_function('random_integer', 2, random.randint)
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Having built a plugin in this way you can turn it into an installable package
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using the following command::
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python3 setup.py sdist
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This will create a ``.tar.gz`` file in the ``dist/`` directory.
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You can then install your new plugin into a Datasette virtual environment or
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Docker container using ``pip``::
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pip install datasette-plugin-demos-0.1.tar.gz
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To learn how to upload your plugin to `PyPI <https://pypi.org/>`_ for use by
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other people, read the PyPA guide to `Packaging and distributing projects
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<https://packaging.python.org/tutorials/distributing-packages/>`_.
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Static assets
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-------------
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If your plugin has a ``static/`` directory, Datasette will automatically
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configure itself to serve those static assets from the following path::
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/-/static-plugins/NAME_OF_PLUGIN_PACKAGE/yourfile.js
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See `the datasette-plugin-demos repository <https://github.com/simonw/datasette-plugin-demos/tree/0ccf9e6189e923046047acd7878d1d19a2cccbb1>`_
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for an example of how to create a package that includes a static folder.
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Custom templates
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----------------
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If your plugin has a ``templates/`` directory, Datasette will attempt to load
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templates from that directory before it uses its own default templates.
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The priority order for template loading is:
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* templates from the ``--template-dir`` argument, if specified
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* templates from the ``templates/`` directory in any installed plugins
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* default templates that ship with Datasette
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See :ref:`customization` for more details on how to write custom templates,
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including which filenames to use to customize which parts of the Datasette UI.
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.. _plugins_configuration:
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Plugin configuration
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--------------------
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Plugins can have their own configuration, embedded in a :ref:`metadata` file. Configuration options for plugins live within a ``"plugins"`` key in that file, which can be included at the root, database or table level.
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Here is an example of some plugin configuration for a specific table::
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{
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"databases: {
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"sf-trees": {
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"tables": {
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"Street_Tree_List": {
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"plugins": {
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"datasette-cluster-map": {
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"latitude_column": "lat",
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"longitude_column": "lng"
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}
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}
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}
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}
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}
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}
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}
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This tells the ``datasette-cluster-map`` column which latitude and longitude columns should be used for a table called ``Street_Tree_List`` inside a database file called ``sf-trees.db``.
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.. _plugins_configuration_secret:
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Secret configuration values
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Any values embedded in ``metadata.json`` will be visible to anyone who views the ``/-/metadata`` page of your Datasette instance. Some plugins may need configuration that should stay secret - API keys for example. There are two ways in which you can store secret configuration values.
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**As environment variables**. If your secret lives in an environment variable that is available to the Datasette process, you can indicate that the configuration value should be read from that environment variable like so::
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{
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"plugins": {
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"datasette-auth-github": {
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"client_secret": {
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"$env": "GITHUB_CLIENT_SECRET"
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}
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}
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}
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}
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**As values in separate files**. Your secrets can also live in files on disk. To specify a secret should be read from a file, provide the full file path like this::
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{
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"plugins": {
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"datasette-auth-github": {
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"client_secret": {
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"$file": "/secrets/client-secret"
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}
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}
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}
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}
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If you are publishing your data using the :ref:`datasette publish <cli_publish>` family of commands, you can use the ``--plugin-secret`` option to set these secrets at publish time. For example, using Heroku you might run the following command::
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$ datasette publish heroku my_database.db \
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--name my-heroku-app-demo \
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--install=datasette-auth-github \
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--plugin-secret datasette-auth-github client_id your_client_id \
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--plugin-secret datasette-auth-github client_secret your_client_secret
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.. _plugins_plugin_config:
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Writing plugins that accept configuration
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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When you are writing plugins, you can access plugin configuration like this using the ``datasette.plugin_config()`` method. If you know you need plugin configuration for a specific table, you can access it like this::
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plugin_config = datasette.plugin_config(
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"datasette-cluster-map", database="sf-trees", table="Street_Tree_List"
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)
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This will return the ``{"latitude_column": "lat", "longitude_column": "lng"}`` in the above example.
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If it cannot find the requested configuration at the table layer, it will fall back to the database layer and then the root layer. For example, a user may have set the plugin configuration option like so::
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{
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"databases: {
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"sf-trees": {
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"plugins": {
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"datasette-cluster-map": {
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"latitude_column": "xlat",
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"longitude_column": "xlng"
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}
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}
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}
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}
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}
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In this case, the above code would return that configuration for ANY table within the ``sf-trees`` database.
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The plugin configuration could also be set at the top level of ``metadata.json``::
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{
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"title": "This is the top-level title in metadata.json",
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"plugins": {
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"datasette-cluster-map": {
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"latitude_column": "xlat",
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"longitude_column": "xlng"
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}
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}
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}
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Now that ``datasette-cluster-map`` plugin configuration will apply to every table in every database.
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.. _plugin_hooks:
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Plugin hooks
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------------
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When you implement a plugin hook you can accept any or all of the parameters that are documented as being passed to that hook. For example, you can implement a ``render_cell`` plugin hook like this even though the hook definition defines more parameters than just ``value`` and ``column``:
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.. code-block:: python
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@hookimpl
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def render_cell(value, column):
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if column == "stars":
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return "*" * int(value)
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The full list of available plugin hooks is as follows.
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.. _plugin_hook_prepare_connection:
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prepare_connection(conn, database, datasette)
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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``conn`` - sqlite3 connection object
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The connection that is being opened
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``database`` - string
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The name of the database
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``datasette`` - :ref:`internals_datasette`
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You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``
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This hook is called when a new SQLite database connection is created. You can
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use it to `register custom SQL functions <https://docs.python.org/2/library/sqlite3.html#sqlite3.Connection.create_function>`_,
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aggregates and collations. For example:
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.. code-block:: python
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from datasette import hookimpl
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import random
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@hookimpl
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def prepare_connection(conn):
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conn.create_function('random_integer', 2, random.randint)
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This registers a SQL function called ``random_integer`` which takes two
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arguments and can be called like this::
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select random_integer(1, 10);
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Examples: `datasette-jellyfish <https://github.com/simonw/datasette-jellyfish>`_, `datasette-jq <https://github.com/simonw/datasette-jq>`_, `datasette-haversine <https://github.com/simonw/datasette-haversine>`__, `datasette-rure <https://github.com/simonw/datasette-rure>`__
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.. _plugin_hook_prepare_jinja2_environment:
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prepare_jinja2_environment(env)
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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``env`` - jinja2 Environment
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The template environment that is being prepared
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This hook is called with the Jinja2 environment that is used to evaluate
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Datasette HTML templates. You can use it to do things like `register custom
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template filters <http://jinja.pocoo.org/docs/2.10/api/#custom-filters>`_, for
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example:
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.. code-block:: python
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from datasette import hookimpl
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@hookimpl
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def prepare_jinja2_environment(env):
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env.filters['uppercase'] = lambda u: u.upper()
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You can now use this filter in your custom templates like so::
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Table name: {{ table|uppercase }}
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.. _plugin_hook_extra_css_urls:
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extra_css_urls(template, database, table, datasette)
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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``template`` - string
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The template that is being rendered, e.g. ``database.html``
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``database`` - string or None
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The name of the database
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``table`` - string or None
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The name of the table
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``datasette`` - :ref:`internals_datasette`
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You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``
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Return a list of extra CSS URLs that should be included on the page. These can
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take advantage of the CSS class hooks described in :ref:`customization`.
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This can be a list of URLs:
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.. code-block:: python
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from datasette import hookimpl
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@hookimpl
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def extra_css_urls():
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return [
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'https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css'
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]
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Or a list of dictionaries defining both a URL and an
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`SRI hash <https://www.srihash.org/>`_:
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.. code-block:: python
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from datasette import hookimpl
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@hookimpl
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def extra_css_urls():
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return [{
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'url': 'https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css',
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'sri': 'sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4',
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}]
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Examples: `datasette-cluster-map <https://github.com/simonw/datasette-cluster-map>`_, `datasette-vega <https://github.com/simonw/datasette-vega>`_
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.. _plugin_hook_extra_js_urls:
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extra_js_urls(template, database, table, datasette)
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Same arguments as ``extra_css_urls``.
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This works in the same way as ``extra_css_urls()`` but for JavaScript. You can
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return either a list of URLs or a list of dictionaries:
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.. code-block:: python
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from datasette import hookimpl
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@hookimpl
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def extra_js_urls():
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return [{
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'url': 'https://code.jquery.com/jquery-3.3.1.slim.min.js',
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'sri': 'sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo',
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}]
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You can also return URLs to files from your plugin's ``static/`` directory, if
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you have one:
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.. code-block:: python
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from datasette import hookimpl
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@hookimpl
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def extra_js_urls():
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return [
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'/-/static-plugins/your-plugin/app.js'
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]
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Examples: `datasette-cluster-map <https://github.com/simonw/datasette-cluster-map>`_, `datasette-vega <https://github.com/simonw/datasette-vega>`_
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.. _plugin_hook_publish_subcommand:
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publish_subcommand(publish)
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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``publish`` - Click publish command group
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The Click command group for the ``datasette publish`` subcommand
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This hook allows you to create new providers for the ``datasette publish``
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command. Datasette uses this hook internally to implement the default ``now``
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and ``heroku`` subcommands, so you can read
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`their source <https://github.com/simonw/datasette/tree/master/datasette/publish>`_
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to see examples of this hook in action.
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Let's say you want to build a plugin that adds a ``datasette publish my_hosting_provider --api_key=xxx mydatabase.db`` publish command. Your implementation would start like this:
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.. code-block:: python
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from datasette import hookimpl
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from datasette.publish.common import add_common_publish_arguments_and_options
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import click
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@hookimpl
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def publish_subcommand(publish):
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@publish.command()
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@add_common_publish_arguments_and_options
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@click.option(
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"-k",
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"--api_key",
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help="API key for talking to my hosting provider",
|
|
)
|
|
def my_hosting_provider(
|
|
files,
|
|
metadata,
|
|
extra_options,
|
|
branch,
|
|
template_dir,
|
|
plugins_dir,
|
|
static,
|
|
install,
|
|
plugin_secret,
|
|
version_note,
|
|
secret,
|
|
title,
|
|
license,
|
|
license_url,
|
|
source,
|
|
source_url,
|
|
about,
|
|
about_url,
|
|
api_key,
|
|
):
|
|
# Your implementation goes here
|
|
|
|
Examples: `datasette-publish-fly <https://github.com/simonw/datasette-publish-fly>`_, `datasette-publish-now <https://github.com/simonw/datasette-publish-now>`_
|
|
|
|
.. _plugin_hook_render_cell:
|
|
|
|
render_cell(value, column, table, database, datasette)
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Lets you customize the display of values within table cells in the HTML table view.
|
|
|
|
``value`` - string, integer or None
|
|
The value that was loaded from the database
|
|
|
|
``column`` - string
|
|
The name of the column being rendered
|
|
|
|
``table`` - string or None
|
|
The name of the table - or ``None`` if this is a custom SQL query
|
|
|
|
``database`` - string
|
|
The name of the database
|
|
|
|
``datasette`` - :ref:`internals_datasette`
|
|
You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``
|
|
|
|
If your hook returns ``None``, it will be ignored. Use this to indicate that your hook is not able to custom render this particular value.
|
|
|
|
If the hook returns a string, that string will be rendered in the table cell.
|
|
|
|
If you want to return HTML markup you can do so by returning a ``jinja2.Markup`` object.
|
|
|
|
Datasette will loop through all available ``render_cell`` hooks and display the value returned by the first one that does not return ``None``.
|
|
|
|
Here is an example of a custom ``render_cell()`` plugin which looks for values that are a JSON string matching the following format::
|
|
|
|
{"href": "https://www.example.com/", "label": "Name"}
|
|
|
|
If the value matches that pattern, the plugin returns an HTML link element:
|
|
|
|
.. code-block:: python
|
|
|
|
from datasette import hookimpl
|
|
import jinja2
|
|
import json
|
|
|
|
|
|
@hookimpl
|
|
def render_cell(value):
|
|
# Render {"href": "...", "label": "..."} as link
|
|
if not isinstance(value, str):
|
|
return None
|
|
stripped = value.strip()
|
|
if not stripped.startswith("{") and stripped.endswith("}"):
|
|
return None
|
|
try:
|
|
data = json.loads(value)
|
|
except ValueError:
|
|
return None
|
|
if not isinstance(data, dict):
|
|
return None
|
|
if set(data.keys()) != {"href", "label"}:
|
|
return None
|
|
href = data["href"]
|
|
if not (
|
|
href.startswith("/") or href.startswith("http://")
|
|
or href.startswith("https://")
|
|
):
|
|
return None
|
|
return jinja2.Markup('<a href="{href}">{label}</a>'.format(
|
|
href=jinja2.escape(data["href"]),
|
|
label=jinja2.escape(data["label"] or "") or " "
|
|
))
|
|
|
|
Examples: `datasette-render-binary <https://github.com/simonw/datasette-render-binary>`_, `datasette-render-markdown <https://github.com/simonw/datasette-render-markdown>`_
|
|
|
|
.. _plugin_hook_extra_body_script:
|
|
|
|
extra_body_script(template, database, table, view_name, datasette)
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Extra JavaScript to be added to a ``<script>`` block at the end of the ``<body>`` element on the page.
|
|
|
|
``template`` - string
|
|
The template that is being rendered, e.g. ``database.html``
|
|
|
|
``database`` - string or None
|
|
The name of the database, or ``None`` if the page does not correspond to a database (e.g. the root page)
|
|
|
|
``table`` - string or None
|
|
The name of the table, or ``None`` if the page does not correct to a table
|
|
|
|
``view_name`` - string
|
|
The name of the view being displayed. (`index`, `database`, `table`, and `row` are the most important ones.)
|
|
|
|
``datasette`` - :ref:`internals_datasette`
|
|
You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``
|
|
|
|
The ``template``, ``database`` and ``table`` options can be used to return different code depending on which template is being rendered and which database or table are being processed.
|
|
|
|
The ``datasette`` instance is provided primarily so that you can consult any plugin configuration options that may have been set, using the ``datasette.plugin_config(plugin_name)`` method documented above.
|
|
|
|
The string that you return from this function will be treated as "safe" for inclusion in a ``<script>`` block directly in the page, so it is up to you to apply any necessary escaping.
|
|
|
|
Example: `datasette-cluster-map <https://github.com/simonw/datasette-cluster-map>`_
|
|
|
|
.. _plugin_hook_extra_template_vars:
|
|
|
|
extra_template_vars(template, database, table, view_name, request, datasette)
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Extra template variables that should be made available in the rendered template context.
|
|
|
|
``template`` - string
|
|
The template that is being rendered, e.g. ``database.html``
|
|
|
|
``database`` - string or None
|
|
The name of the database, or ``None`` if the page does not correspond to a database (e.g. the root page)
|
|
|
|
``table`` - string or None
|
|
The name of the table, or ``None`` if the page does not correct to a table
|
|
|
|
``view_name`` - string
|
|
The name of the view being displayed. (`index`, `database`, `table`, and `row` are the most important ones.)
|
|
|
|
``request`` - object
|
|
The current HTTP :ref:`internals_request`.
|
|
|
|
``datasette`` - :ref:`internals_datasette`
|
|
You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``
|
|
|
|
This hook can return one of three different types:
|
|
|
|
Dictionary
|
|
If you return a dictionary its keys and values will be merged into the template context.
|
|
|
|
Function that returns a dictionary
|
|
If you return a function it will be executed. If it returns a dictionary those values will will be merged into the template context.
|
|
|
|
Function that returns an awaitable function that returns a dictionary
|
|
You can also return a function which returns an awaitable function which returns a dictionary.
|
|
|
|
Datasette runs Jinja2 in `async mode <https://jinja.palletsprojects.com/en/2.10.x/api/#async-support>`__, which means you can add awaitable functions to the template scope and they will be automatically awaited when they are rendered by the template.
|
|
|
|
Here's an example plugin that adds a ``"user_agent"`` variable to the template context containing the current request's User-Agent header:
|
|
|
|
.. code-block:: python
|
|
|
|
@hookimpl
|
|
def extra_template_vars(request):
|
|
return {
|
|
"user_agent": request.headers.get("user-agent")
|
|
}
|
|
|
|
This example returns an awaitable function which adds a list of ``hidden_table_names`` to the context:
|
|
|
|
.. code-block:: python
|
|
|
|
@hookimpl
|
|
def extra_template_vars(datasette, database):
|
|
async def hidden_table_names():
|
|
if database:
|
|
db = datasette.databases[database]
|
|
return {"hidden_table_names": await db.hidden_table_names()}
|
|
else:
|
|
return {}
|
|
return hidden_table_names
|
|
|
|
And here's an example which adds a ``sql_first(sql_query)`` function which executes a SQL statement and returns the first column of the first row of results:
|
|
|
|
.. code-block:: python
|
|
|
|
@hookimpl
|
|
def extra_template_vars(datasette, database):
|
|
async def sql_first(sql, dbname=None):
|
|
dbname = dbname or database or next(iter(datasette.databases.keys()))
|
|
return (await datasette.execute(dbname, sql)).rows[0][0]
|
|
return {"sql_first": sql_first}
|
|
|
|
You can then use the new function in a template like so::
|
|
|
|
SQLite version: {{ sql_first("select sqlite_version()") }}
|
|
|
|
Examples: `datasette-search-all <https://github.com/simonw/datasette-search-all>`_, `datasette-template-sql <https://github.com/simonw/datasette-template-sql>`_
|
|
|
|
.. _plugin_register_output_renderer:
|
|
|
|
register_output_renderer(datasette)
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
``datasette`` - :ref:`internals_datasette`
|
|
You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``
|
|
|
|
Registers a new output renderer, to output data in a custom format. The hook function should return a dictionary, or a list of dictionaries, of the following shape:
|
|
|
|
.. code-block:: python
|
|
|
|
@hookimpl
|
|
def register_output_renderer(datasette):
|
|
return {
|
|
"extension": "test",
|
|
"render": render_demo,
|
|
"can_render": can_render_demo, # Optional
|
|
}
|
|
|
|
This will register ``render_demo`` to be called when paths with the extension ``.test`` (for example ``/database.test``, ``/database/table.test``, or ``/database/table/row.test``) are requested.
|
|
|
|
``render_demo`` is a Python function. It can be a regular function or an ``async def render_demo()`` awaitable function, depending on if it needs to make any asynchronous calls.
|
|
|
|
``can_render_demo`` is a Python function (or ``async def`` function) which acepts the same arguments as ``render_demo`` but just returns ``True`` or ``False``. It lets Datasette know if the current SQL query can be represented by the plugin - and hence influnce if a link to this output format is displayed in the user interface. If you omit the ``"can_render"`` key from the dictionary every query will be treated as being supported by the plugin.
|
|
|
|
When a request is received, the ``"render"`` callback function is called with zero or more of the following arguments. Datasette will inspect your callback function and pass arguments that match its function signature.
|
|
|
|
``datasette`` - :ref:`internals_datasette`
|
|
For accessing plugin configuration and executing queries.
|
|
|
|
``columns`` - list of strings
|
|
The names of the columns returned by this query.
|
|
|
|
``rows`` - list of ``sqlite3.Row`` objects
|
|
The rows returned by the query.
|
|
|
|
``sql`` - string
|
|
The SQL query that was executed.
|
|
|
|
``query_name`` - string or None
|
|
If this was the execution of a :ref:`canned query <canned_queries>`, the name of that query.
|
|
|
|
``database`` - string
|
|
The name of the database.
|
|
|
|
``table`` - string or None
|
|
The table or view, if one is being rendered.
|
|
|
|
``request`` - :ref:`internals_request`
|
|
The incoming HTTP request.
|
|
|
|
``view_name`` - string
|
|
The name of the current view being called. ``index``, ``database``, ``table``, and ``row`` are the most important ones.
|
|
|
|
The callback function can return ``None``, if it is unable to render the data, or a dictionary with the following keys:
|
|
|
|
``body`` - string or bytes, optional
|
|
The response body, default empty
|
|
|
|
``content_type`` - string, optional
|
|
The Content-Type header, default ``text/plain``
|
|
|
|
``status_code`` - integer, optional
|
|
The HTTP status code, default 200
|
|
|
|
``headers`` - dictionary, optional
|
|
Extra HTTP headers to be returned in the response.
|
|
|
|
A simple example of an output renderer callback function:
|
|
|
|
.. code-block:: python
|
|
|
|
def render_demo():
|
|
return {
|
|
"body": "Hello World"
|
|
}
|
|
|
|
Here is a more complex example:
|
|
|
|
.. code-block:: python
|
|
|
|
async def render_demo(datasette, columns, rows):
|
|
db = datasette.get_database()
|
|
result = await db.execute("select sqlite_version()")
|
|
first_row = " | ".join(columns)
|
|
lines = [first_row]
|
|
lines.append("=" * len(first_row))
|
|
for row in rows:
|
|
lines.append(" | ".join(row))
|
|
return {
|
|
"body": "\n".join(lines),
|
|
"content_type": "text/plain; charset=utf-8",
|
|
"headers": {"x-sqlite-version": result.first()[0]},
|
|
}
|
|
|
|
And here is an example ``can_render`` function which returns ``True`` only if the query results contain the columns ``atom_id``, ``atom_title`` and ``atom_updated``:
|
|
|
|
.. code-block:: python
|
|
|
|
def can_render_demo(columns):
|
|
return {"atom_id", "atom_title", "atom_updated"}.issubset(columns)
|
|
|
|
Examples: `datasette-atom <https://github.com/simonw/datasette-atom>`_, `datasette-ics <https://github.com/simonw/datasette-ics>`_
|
|
|
|
.. _plugin_register_routes:
|
|
|
|
register_routes()
|
|
~~~~~~~~~~~~~~~~~
|
|
|
|
Register additional view functions to execute for specified URL routes.
|
|
|
|
Return a list of ``(regex, async_view_function)`` pairs, something like this:
|
|
|
|
.. code-block:: python
|
|
|
|
from datasette.utils.asgi import Response
|
|
import html
|
|
|
|
|
|
async def hello_from(request):
|
|
name = request.url_vars["name"]
|
|
return Response.html("Hello from {}".format(
|
|
html.escape(name)
|
|
))
|
|
|
|
|
|
@hookimpl
|
|
def register_routes():
|
|
return [
|
|
(r"^/hello-from/(?P<name>.*)$"), hello_from)
|
|
]
|
|
|
|
The view functions can take a number of different optional arguments. The corresponding argument will be passed to your function depending on its named parameters - a form of dependency injection.
|
|
|
|
The optional view function arguments are as follows:
|
|
|
|
``datasette`` - :ref:`internals_datasette`
|
|
You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``, or to execute SQL queries.
|
|
|
|
``request`` - Request object
|
|
The current HTTP :ref:`internals_request`.
|
|
|
|
``scope`` - dictionary
|
|
The incoming ASGI scope dictionary.
|
|
|
|
``send`` - function
|
|
The ASGI send function.
|
|
|
|
``receive`` - function
|
|
The ASGI receive function.
|
|
|
|
The function can either return a :ref:`internals_response` or it can return nothing and instead respond directly to the request using the ASGI ``send`` function (for advanced uses only).
|
|
|
|
.. _plugin_register_facet_classes:
|
|
|
|
register_facet_classes()
|
|
~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Return a list of additional Facet subclasses to be registered.
|
|
|
|
.. warning::
|
|
The design of this plugin hook is unstable and may change. See `issue 830 <https://github.com/simonw/datasette/issues/830>`__.
|
|
|
|
Each Facet subclass implements a new type of facet operation. The class should look like this:
|
|
|
|
.. code-block:: python
|
|
|
|
class SpecialFacet(Facet):
|
|
# This key must be unique across all facet classes:
|
|
type = "special"
|
|
|
|
async def suggest(self):
|
|
# Use self.sql and self.params to suggest some facets
|
|
suggested_facets = []
|
|
suggested_facets.append({
|
|
"name": column, # Or other unique name
|
|
# Construct the URL that will enable this facet:
|
|
"toggle_url": self.ds.absolute_url(
|
|
self.request, path_with_added_args(
|
|
self.request, {"_facet": column}
|
|
)
|
|
),
|
|
})
|
|
return suggested_facets
|
|
|
|
async def facet_results(self):
|
|
# This should execute the facet operation and return results, again
|
|
# using self.sql and self.params as the starting point
|
|
facet_results = {}
|
|
facets_timed_out = []
|
|
# Do some calculations here...
|
|
for column in columns_selected_for_facet:
|
|
try:
|
|
facet_results_values = []
|
|
# More calculations...
|
|
facet_results_values.append({
|
|
"value": value,
|
|
"label": label,
|
|
"count": count,
|
|
"toggle_url": self.ds.absolute_url(self.request, toggle_path),
|
|
"selected": selected,
|
|
})
|
|
facet_results[column] = {
|
|
"name": column,
|
|
"results": facet_results_values,
|
|
"truncated": len(facet_rows_results) > facet_size,
|
|
}
|
|
except QueryInterrupted:
|
|
facets_timed_out.append(column)
|
|
|
|
return facet_results, facets_timed_out
|
|
|
|
See `datasette/facets.py <https://github.com/simonw/datasette/blob/master/datasette/facets.py>`__ for examples of how these classes can work.
|
|
|
|
The plugin hook can then be used to register the new facet class like this:
|
|
|
|
.. code-block:: python
|
|
|
|
@hookimpl
|
|
def register_facet_classes():
|
|
return [SpecialFacet]
|
|
|
|
.. _plugin_asgi_wrapper:
|
|
|
|
asgi_wrapper(datasette)
|
|
~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Return an `ASGI <https://asgi.readthedocs.io/>`__ middleware wrapper function that will be applied to the Datasette ASGI application.
|
|
|
|
This is a very powerful hook. You can use it to manipulate the entire Datasette response, or even to configure new URL routes that will be handled by your own custom code.
|
|
|
|
You can write your ASGI code directly against the low-level specification, or you can use the middleware utilites provided by an ASGI framework such as `Starlette <https://www.starlette.io/middleware/>`__.
|
|
|
|
This example plugin adds a ``x-databases`` HTTP header listing the currently attached databases:
|
|
|
|
.. code-block:: python
|
|
|
|
from datasette import hookimpl
|
|
from functools import wraps
|
|
|
|
|
|
@hookimpl
|
|
def asgi_wrapper(datasette):
|
|
def wrap_with_databases_header(app):
|
|
@wraps(app)
|
|
async def add_x_databases_header(scope, recieve, send):
|
|
async def wrapped_send(event):
|
|
if event["type"] == "http.response.start":
|
|
original_headers = event.get("headers") or []
|
|
event = {
|
|
"type": event["type"],
|
|
"status": event["status"],
|
|
"headers": original_headers + [
|
|
[b"x-databases",
|
|
", ".join(datasette.databases.keys()).encode("utf-8")]
|
|
],
|
|
}
|
|
await send(event)
|
|
await app(scope, recieve, wrapped_send)
|
|
return add_x_databases_header
|
|
return wrap_with_databases_header
|
|
|
|
Examples: `datasette-auth-github <https://github.com/simonw/datasette-auth-github>`_, `datasette-search-all <https://github.com/simonw/datasette-search-all>`_, `datasette-media <https://github.com/simonw/datasette-media>`_
|
|
|
|
.. _plugin_hook_startup:
|
|
|
|
startup(datasette)
|
|
~~~~~~~~~~~~~~~~~~
|
|
|
|
This hook fires when the Datasette application server first starts up. You can implement a regular function, for example to validate required plugin configuration:
|
|
|
|
.. code-block:: python
|
|
|
|
@hookimpl
|
|
def startup(datasette):
|
|
config = datasette.plugin_config("my-plugin") or {}
|
|
assert "required-setting" in config, "my-plugin requires setting required-setting"
|
|
|
|
Or you can return an async function which will be awaited on startup. Use this option if you need to make any database queries:
|
|
|
|
.. code-block:: python
|
|
|
|
@hookimpl
|
|
def startup(datasette):
|
|
async def inner():
|
|
db = datasette.get_database()
|
|
if "my_table" not in await db.table_names():
|
|
await db.execute_write("""
|
|
create table my_table (mycol text)
|
|
""", block=True)
|
|
return inner
|
|
|
|
Potential use-cases:
|
|
|
|
* Run some initialization code for the plugin
|
|
* Create database tables that a plugin needs
|
|
* Validate the metadata configuration for a plugin on startup, and raise an error if it is invalid
|
|
|
|
.. _plugin_hook_actor_from_request:
|
|
|
|
actor_from_request(datasette, request)
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
``datasette`` - :ref:`internals_datasette`
|
|
You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``, or to execute SQL queries.
|
|
|
|
``request`` - object
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The current HTTP :ref:`internals_request`.
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This is part of Datasette's :ref:`authentication and permissions system <authentication>`. The function should attempt to authenticate an actor (either a user or an API actor of some sort) based on information in the request.
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If it cannot authenticate an actor, it should return ``None``. Otherwise it should return a dictionary representing that actor.
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|
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Here's an example that authenticates the actor based on an incoming API key:
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.. code-block:: python
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from datasette import hookimpl
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import secrets
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SECRET_KEY = "this-is-a-secret"
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|
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@hookimpl
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def actor_from_request(datasette, request):
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authorization = request.headers.get("authorization") or ""
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expected = "Bearer {}".format(SECRET_KEY)
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|
|
|
if secrets.compare_digest(authorization, expected):
|
|
return {"id": "bot"}
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|
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If you install this in your plugins directory you can test it like this::
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|
|
$ curl -H 'Authorization: Bearer this-is-a-secret' http://localhost:8003/-/actor.json
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|
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Instead of returning a dictionary, this function can return an awaitable function which itself returns either ``None`` or a dictionary. This is useful for authentication functions that need to make a database query - for example:
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|
|
|
.. code-block:: python
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|
|
|
from datasette import hookimpl
|
|
|
|
@hookimpl
|
|
def actor_from_request(datasette, request):
|
|
async def inner():
|
|
token = request.args.get("_token")
|
|
if not token:
|
|
return None
|
|
# Look up ?_token=xxx in sessions table
|
|
result = await datasette.get_database().execute(
|
|
"select count(*) from sessions where token = ?", [token]
|
|
)
|
|
if result.first()[0]:
|
|
return {"token": token}
|
|
else:
|
|
return None
|
|
|
|
return inner
|
|
|
|
Example: `datasette-auth-tokens <https://github.com/simonw/datasette-auth-tokens>`_
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|
|
|
.. _plugin_hook_permission_allowed:
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|
|
|
permission_allowed(datasette, actor, action, resource)
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
``datasette`` - :ref:`internals_datasette`
|
|
You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``, or to execute SQL queries.
|
|
|
|
``actor`` - dictionary
|
|
The current actor, as decided by :ref:`plugin_hook_actor_from_request`.
|
|
|
|
``action`` - string
|
|
The action to be performed, e.g. ``"edit-table"``.
|
|
|
|
``resource`` - string or None
|
|
An identifier for the individual resource, e.g. the name of the table.
|
|
|
|
Called to check that an actor has permission to perform an action on a resource. Can return ``True`` if the action is allowed, ``False`` if the action is not allowed or ``None`` if the plugin does not have an opinion one way or the other.
|
|
|
|
Here's an example plugin which randomly selects if a permission should be allowed or denied, except for ``view-instance`` which always uses the default permission scheme instead.
|
|
|
|
.. code-block:: python
|
|
|
|
from datasette import hookimpl
|
|
import random
|
|
|
|
@hookimpl
|
|
def permission_allowed(action):
|
|
if action != "view-instance":
|
|
# Return True or False at random
|
|
return random.random() > 0.5
|
|
# Returning None falls back to default permissions
|
|
|
|
This function can alternatively return an awaitable function which itself returns ``True``, ``False`` or ``None``. You can use this option if you need to execute additional database queries using ``await datasette.execute(...)``.
|
|
|
|
Here's an example that allows users to view the ``admin_log`` table only if their actor ``id`` is present in the ``admin_users`` table. It aso disallows arbitrary SQL queries for the ``staff.db`` database for all users.
|
|
|
|
.. code-block:: python
|
|
|
|
@hookimpl
|
|
def permission_allowed(datasette, actor, action, resource):
|
|
async def inner():
|
|
if action == "execute-sql" and resource == "staff":
|
|
return False
|
|
if action == "view-table" and resource == ("staff", "admin_log"):
|
|
if not actor:
|
|
return False
|
|
user_id = actor["id"]
|
|
return await datasette.get_database("staff").execute(
|
|
"select count(*) from admin_users where user_id = :user_id",
|
|
{"user_id": user_id},
|
|
)
|
|
|
|
return inner
|
|
|
|
See :ref:`built-in permissions <permissions>` for a full list of permissions that are included in Datasette core.
|
|
|
|
Example: `datasette-permissions-sql <https://github.com/simonw/datasette-permissions-sql>`_
|