kopia lustrzana https://github.com/simonw/datasette
990 wiersze
36 KiB
ReStructuredText
990 wiersze
36 KiB
ReStructuredText
.. _plugin_hooks:
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Plugin hooks
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============
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Datasette :ref:`plugins <plugins>` use *plugin hooks* to customize Datasette's behavior. These hooks are powered by the `pluggy <https://pluggy.readthedocs.io/>`__ plugin system.
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Each plugin can implement one or more hooks using the ``@hookimpl`` decorator against a function named that matches one of the hooks documented on this page.
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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.
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For example, you can implement the ``render_cell`` plugin hook like this even though the full documented hook signature is ``render_cell(value, column, table, database, datasette)``:
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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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.. contents:: List of plugin hooks
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:local:
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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_template_vars:
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extra_template_vars(template, database, table, columns, view_name, request, datasette)
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--------------------------------------------------------------------------------------
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Extra template variables that should be made available in the rendered template context.
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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, or ``None`` if the page does not correspond to a database (e.g. the root page)
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``table`` - string or None
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The name of the table, or ``None`` if the page does not correct to a table
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``columns`` - list of strings or None
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The names of the database columns that will be displayed on this page. ``None`` if the page does not contain a table.
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``view_name`` - string
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The name of the view being displayed. (``index``, ``database``, ``table``, and ``row`` are the most important ones.)
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``request`` - object or None
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The current HTTP :ref:`internals_request`. This can be ``None`` if the request object is not available.
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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 can return one of three different types:
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Dictionary
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If you return a dictionary its keys and values will be merged into the template context.
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Function that returns a dictionary
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If you return a function it will be executed. If it returns a dictionary those values will will be merged into the template context.
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Function that returns an awaitable function that returns a dictionary
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You can also return a function which returns an awaitable function which returns a dictionary.
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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.
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Here's an example plugin that adds a ``"user_agent"`` variable to the template context containing the current request's User-Agent header:
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.. code-block:: python
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@hookimpl
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def extra_template_vars(request):
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return {
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"user_agent": request.headers.get("user-agent")
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}
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This example returns an awaitable function which adds a list of ``hidden_table_names`` to the context:
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.. code-block:: python
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@hookimpl
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def extra_template_vars(datasette, database):
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async def hidden_table_names():
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if database:
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db = datasette.databases[database]
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return {"hidden_table_names": await db.hidden_table_names()}
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else:
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return {}
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return hidden_table_names
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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:
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.. code-block:: python
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@hookimpl
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def extra_template_vars(datasette, database):
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async def sql_first(sql, dbname=None):
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dbname = dbname or database or next(iter(datasette.databases.keys()))
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return (await datasette.execute(dbname, sql)).rows[0][0]
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return {"sql_first": sql_first}
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You can then use the new function in a template like so::
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SQLite version: {{ sql_first("select sqlite_version()") }}
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Examples: `datasette-search-all <https://github.com/simonw/datasette-search-all>`_, `datasette-template-sql <https://github.com/simonw/datasette-template-sql>`_
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.. _plugin_hook_extra_css_urls:
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extra_css_urls(template, database, table, columns, view_name, request, datasette)
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---------------------------------------------------------------------------------
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Same arguments as :ref:`extra_template_vars(...) <plugin_hook_extra_template_vars>`
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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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This function can also return an awaitable function, useful if it needs to run any async code:
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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(datasette):
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async def inner():
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db = datasette.get_database()
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results = await db.execute("select url from css_files")
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return [r[0] for r in results]
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return inner
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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, columns, view_name, request, datasette)
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--------------------------------------------------------------------------------
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Same arguments as :ref:`extra_template_vars(...) <plugin_hook_extra_template_vars>`
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This works in the same way as ``extra_css_urls()`` but for JavaScript. You can
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return a list of URLs, a list of dictionaries or an awaitable function that returns those things:
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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_extra_body_script:
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extra_body_script(template, database, table, columns, view_name, request, datasette)
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------------------------------------------------------------------------------------
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Extra JavaScript to be added to a ``<script>`` block at the end of the ``<body>`` element on the page.
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Same arguments as :ref:`extra_template_vars(...) <plugin_hook_extra_template_vars>`
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The ``template``, ``database``, ``table`` and ``view_name`` options can be used to return different code depending on which template is being rendered and which database or table are being processed.
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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.
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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.
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You can also return an awaitable function that returns a string.
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Example: `datasette-cluster-map <https://github.com/simonw/datasette-cluster-map>`_
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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",
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)
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def my_hosting_provider(
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files,
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metadata,
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extra_options,
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branch,
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template_dir,
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plugins_dir,
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static,
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install,
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plugin_secret,
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version_note,
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secret,
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title,
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license,
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license_url,
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source,
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source_url,
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about,
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about_url,
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api_key,
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):
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# Your implementation goes here
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Examples: `datasette-publish-fly <https://github.com/simonw/datasette-publish-fly>`_, `datasette-publish-now <https://github.com/simonw/datasette-publish-now>`_
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.. _plugin_hook_render_cell:
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render_cell(value, column, table, database, datasette)
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------------------------------------------------------
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Lets you customize the display of values within table cells in the HTML table view.
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``value`` - string, integer or None
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The value that was loaded from the database
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``column`` - string
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The name of the column being rendered
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``table`` - string or None
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The name of the table - or ``None`` if this is a custom SQL query
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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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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.
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If the hook returns a string, that string will be rendered in the table cell.
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If you want to return HTML markup you can do so by returning a ``jinja2.Markup`` object.
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Datasette will loop through all available ``render_cell`` hooks and display the value returned by the first one that does not return ``None``.
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Here is an example of a custom ``render_cell()`` plugin which looks for values that are a JSON string matching the following format::
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{"href": "https://www.example.com/", "label": "Name"}
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If the value matches that pattern, the plugin returns an HTML link element:
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.. code-block:: python
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from datasette import hookimpl
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import jinja2
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import json
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@hookimpl
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def render_cell(value):
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# Render {"href": "...", "label": "..."} as link
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if not isinstance(value, str):
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return None
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stripped = value.strip()
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if not stripped.startswith("{") and stripped.endswith("}"):
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return None
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try:
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data = json.loads(value)
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except ValueError:
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return None
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if not isinstance(data, dict):
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return None
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if set(data.keys()) != {"href", "label"}:
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return None
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href = data["href"]
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if not (
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href.startswith("/") or href.startswith("http://")
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or href.startswith("https://")
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):
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return None
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return jinja2.Markup('<a href="{href}">{label}</a>'.format(
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href=jinja2.escape(data["href"]),
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label=jinja2.escape(data["label"] or "") or " "
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))
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Examples: `datasette-render-binary <https://github.com/simonw/datasette-render-binary>`_, `datasette-render-markdown <https://github.com/simonw/datasette-render-markdown>`_
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.. _plugin_register_output_renderer:
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register_output_renderer(datasette)
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-----------------------------------
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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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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:
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.. code-block:: python
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@hookimpl
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def register_output_renderer(datasette):
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return {
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"extension": "test",
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"render": render_demo,
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"can_render": can_render_demo, # Optional
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}
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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.
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``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.
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``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.
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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.
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``datasette`` - :ref:`internals_datasette`
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For accessing plugin configuration and executing queries.
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``columns`` - list of strings
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The names of the columns returned by this query.
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``rows`` - list of ``sqlite3.Row`` objects
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The rows returned by the query.
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``sql`` - string
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The SQL query that was executed.
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``query_name`` - string or None
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If this was the execution of a :ref:`canned query <canned_queries>`, the name of that query.
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``database`` - string
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The name of the database.
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``table`` - string or None
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The table or view, if one is being rendered.
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``request`` - :ref:`internals_request`
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The incoming HTTP request.
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``view_name`` - string
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The name of the current view being called. ``index``, ``database``, ``table``, and ``row`` are the most important ones.
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The callback function can return ``None``, if it is unable to render the data, or a :ref:`internals_response` that will be returned to the caller.
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It can also return a dictionary with the following keys. This format is **deprecated** as-of Datasette 0.49 and will be removed by Datasette 1.0.
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``body`` - string or bytes, optional
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The response body, default empty
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``content_type`` - string, optional
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The Content-Type header, default ``text/plain``
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``status_code`` - integer, optional
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The HTTP status code, default 200
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``headers`` - dictionary, optional
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Extra HTTP headers to be returned in the response.
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A simple example of an output renderer callback function:
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.. code-block:: python
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def render_demo():
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return Response.text("Hello World")
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Here is a more complex example:
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.. code-block:: python
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async def render_demo(datasette, columns, rows):
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db = datasette.get_database()
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result = await db.execute("select sqlite_version()")
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first_row = " | ".join(columns)
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lines = [first_row]
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lines.append("=" * len(first_row))
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for row in rows:
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lines.append(" | ".join(row))
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return Response(
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"\n".join(lines),
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content_type="text/plain; charset=utf-8",
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headers={"x-sqlite-version": result.first()[0]}
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)
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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``:
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.. code-block:: python
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def can_render_demo(columns):
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return {"atom_id", "atom_title", "atom_updated"}.issubset(columns)
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|
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, 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 view function can be a regular function or an ``async def`` function, depending on if it needs to use any ``await`` APIs.
|
|
|
|
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).
|
|
|
|
Examples: `datasette-auth-github <https://github.com/simonw/datasette-auth-github>`__, `datasette-psutil <https://github.com/simonw/datasette-psutil>`__
|
|
|
|
.. _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
|
|
|
|
Example: `datasette-cors <https://github.com/simonw/datasette-cors>`_
|
|
|
|
.. _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 on startup
|
|
* Validate the metadata configuration for a plugin on startup, and raise an error if it is invalid
|
|
|
|
.. note::
|
|
|
|
If you are writing :ref:`unit tests <testing_plugins>` for a plugin that uses this hook you will need to explicitly call ``await ds.invoke_startup()`` in your tests. An example:
|
|
|
|
.. code-block:: python
|
|
|
|
@pytest.mark.asyncio
|
|
async def test_my_plugin():
|
|
ds = Datasette([], metadata={})
|
|
await ds.invoke_startup()
|
|
# Rest of test goes here
|
|
|
|
Examples: `datasette-saved-queries <https://github.com/simonw/datasette-saved-queries>`__, `datasette-init <https://github.com/simonw/datasette-init>`__
|
|
|
|
.. _plugin_hook_canned_queries:
|
|
|
|
canned_queries(datasette, database, actor)
|
|
------------------------------------------
|
|
|
|
``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.
|
|
|
|
``database`` - string
|
|
The name of the database.
|
|
|
|
``actor`` - dictionary or None
|
|
The currently authenticated :ref:`actor <authentication_actor>`.
|
|
|
|
Ues this hook to return a dictionary of additional :ref:`canned query <canned_queries>` definitions for the specified database. The return value should be the same shape as the JSON described in the :ref:`canned query <canned_queries>` documentation.
|
|
|
|
.. code-block:: python
|
|
|
|
from datasette import hookimpl
|
|
|
|
@hookimpl
|
|
def canned_queries(datasette, database):
|
|
if database == "mydb":
|
|
return {
|
|
"my_query": {
|
|
"sql": "select * from my_table where id > :min_id"
|
|
}
|
|
}
|
|
|
|
The hook can alternatively return an awaitable function that returns a list. Here's an example that returns queries that have been stored in the ``saved_queries`` database table, if one exists:
|
|
|
|
.. code-block:: python
|
|
|
|
from datasette import hookimpl
|
|
|
|
@hookimpl
|
|
def canned_queries(datasette, database):
|
|
async def inner():
|
|
db = datasette.get_database(database)
|
|
if await db.table_exists("saved_queries"):
|
|
results = await db.execute("select name, sql from saved_queries")
|
|
return {result["name"]: {
|
|
"sql": result["sql"]
|
|
} for result in results}
|
|
return inner
|
|
|
|
The actor parameter can be used to include the currently authenticated actor in your decision. Here's an example that returns saved queries that were saved by that actor:
|
|
|
|
.. code-block:: python
|
|
|
|
from datasette import hookimpl
|
|
|
|
@hookimpl
|
|
def canned_queries(datasette, database, actor):
|
|
async def inner():
|
|
db = datasette.get_database(database)
|
|
if actor is not None and await db.table_exists("saved_queries"):
|
|
results = await db.execute(
|
|
"select name, sql from saved_queries where actor_id = :id", {
|
|
"id": actor["id"]
|
|
}
|
|
)
|
|
return {result["name"]: {
|
|
"sql": result["sql"]
|
|
} for result in results}
|
|
return inner
|
|
|
|
Example: `datasette-saved-queries <https://github.com/simonw/datasette-saved-queries>`__
|
|
|
|
.. _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
|
|
The current HTTP :ref:`internals_request`.
|
|
|
|
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.
|
|
|
|
If it cannot authenticate an actor, it should return ``None``. Otherwise it should return a dictionary representing that actor.
|
|
|
|
Here's an example that authenticates the actor based on an incoming API key:
|
|
|
|
.. code-block:: python
|
|
|
|
from datasette import hookimpl
|
|
import secrets
|
|
|
|
SECRET_KEY = "this-is-a-secret"
|
|
|
|
@hookimpl
|
|
def actor_from_request(datasette, request):
|
|
authorization = request.headers.get("authorization") or ""
|
|
expected = "Bearer {}".format(SECRET_KEY)
|
|
|
|
if secrets.compare_digest(authorization, expected):
|
|
return {"id": "bot"}
|
|
|
|
If you install this in your plugins directory you can test it like this::
|
|
|
|
$ curl -H 'Authorization: Bearer this-is-a-secret' http://localhost:8003/-/actor.json
|
|
|
|
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:
|
|
|
|
.. code-block:: python
|
|
|
|
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>`_
|
|
|
|
.. _plugin_hook_permission_allowed:
|
|
|
|
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>`_
|
|
|
|
.. _plugin_hook_register_magic_parameters:
|
|
|
|
register_magic_parameters(datasette)
|
|
------------------------------------
|
|
|
|
``datasette`` - :ref:`internals_datasette`
|
|
You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``.
|
|
|
|
:ref:`canned_queries_magic_parameters` can be used to add automatic parameters to :ref:`canned queries <canned_queries>`. This plugin hook allows additional magic parameters to be defined by plugins.
|
|
|
|
Magic parameters all take this format: ``_prefix_rest_of_parameter``. The prefix indicates which magic parameter function should be called - the rest of the parameter is passed as an argument to that function.
|
|
|
|
To register a new function, return it as a tuple of ``(string prefix, function)`` from this hook. The function you register should take two arguments: ``key`` and ``request``, where ``key`` is the ``rest_of_parameter`` portion of the parameter and ``request`` is the current :ref:`internals_request`.
|
|
|
|
This example registers two new magic parameters: ``:_request_http_version`` returning the HTTP version of the current request, and ``:_uuid_new`` which returns a new UUID:
|
|
|
|
.. code-block:: python
|
|
|
|
from uuid import uuid4
|
|
|
|
def uuid(key, request):
|
|
if key == "new":
|
|
return str(uuid4())
|
|
else:
|
|
raise KeyError
|
|
|
|
def request(key, request):
|
|
if key == "http_version":
|
|
return request.scope["http_version"]
|
|
else:
|
|
raise KeyError
|
|
|
|
@hookimpl
|
|
def register_magic_parameters(datasette):
|
|
return [
|
|
("request", request),
|
|
("uuid", uuid),
|
|
]
|
|
|
|
.. _plugin_hook_forbidden:
|
|
|
|
forbidden(datasette, request, message)
|
|
--------------------------------------
|
|
|
|
``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
|
|
The current HTTP :ref:`internals_request`.
|
|
|
|
``message`` - string
|
|
A message hinting at why the request was forbidden.
|
|
|
|
Plugins can use this to customize how Datasette responds when a 403 Forbidden error occurs - usually because a page failed a permission check, see :ref:`authentication_permissions`.
|
|
|
|
If a plugin hook wishes to react to the error, it should return a :ref:`Response object <internals_response>`.
|
|
|
|
This example returns a redirect to a ``/-/login`` page:
|
|
|
|
.. code-block:: python
|
|
|
|
from datasette import hookimpl
|
|
from urllib.parse import urlencode
|
|
|
|
@hookimpl
|
|
def forbidden(request, message):
|
|
return Response.redirect("/-/login?=" + urlencode({"message": message}))
|
|
|
|
The function can alternatively return an awaitable function if it needs to make any asynchronous method calls. This example renders a template:
|
|
|
|
.. code-block:: python
|
|
|
|
from datasette import hookimpl
|
|
from datasette.utils.asgi import Response
|
|
|
|
@hookimpl
|
|
def forbidden(datasette):
|
|
async def inner():
|
|
return Response.html(await datasette.render_template("forbidden.html"))
|
|
|
|
return inner
|