prepare_jinja2_environment(datasette) argument, refs #1809

datasette/app.py

@@ -345,7 +345,7 @@ class Datasette:
         self.jinja_env.filters["escape_sqlite"] = escape_sqlite
         self.jinja_env.filters["to_css_class"] = to_css_class
         # pylint: disable=no-member
-        pm.hook.prepare_jinja2_environment(env=self.jinja_env)
+        pm.hook.prepare_jinja2_environment(env=self.jinja_env, datasette=self)
 
         self._register_renderers()
         self._permission_checks = collections.deque(maxlen=200)

datasette/hookspecs.py

@@ -26,7 +26,7 @@ def prepare_connection(conn, database, datasette):
 
 
 @hookspec
-def prepare_jinja2_environment(env):
+def prepare_jinja2_environment(env, datasette):
     """Modify Jinja2 template environment e.g. register custom template tags"""
 
 

docs/plugin_hooks.rst

@@ -61,12 +61,15 @@ Examples: `datasette-jellyfish <https://datasette.io/plugins/datasette-jellyfish
 
 .. _plugin_hook_prepare_jinja2_environment:
 
-prepare_jinja2_environment(env)
--------------------------------
+prepare_jinja2_environment(env, datasette)
+------------------------------------------
 
 ``env`` - jinja2 Environment
     The template environment that is being prepared
 
+``datasette`` - :ref:`internals_datasette`
+    You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``
+
 This hook is called with the Jinja2 environment that is used to evaluate
 Datasette HTML templates. You can use it to do things like `register custom
 template filters <http://jinja.pocoo.org/docs/2.10/api/#custom-filters>`_, for
@@ -85,6 +88,8 @@ You can now use this filter in your custom templates like so::
 
     Table name: {{ table|uppercase }}
 
+Examples: `datasette-edit-templates <https://datasette.io/plugins/datasette-edit-templates>`_
+
 .. _plugin_hook_extra_template_vars:
 
 extra_template_vars(template, database, table, columns, view_name, request, datasette)

tests/plugins/my_plugin.py

@@ -142,8 +142,9 @@ def extra_template_vars(
 
 
 @hookimpl
-def prepare_jinja2_environment(env):
+def prepare_jinja2_environment(env, datasette):
     env.filters["format_numeric"] = lambda s: f"{float(s):,.0f}"
+    env.filters["to_hello"] = lambda s: datasette._HELLO
 
 
 @hookimpl

tests/test_plugins.py

@@ -545,11 +545,12 @@ def test_hook_register_output_renderer_can_render(app_client):
 
 @pytest.mark.asyncio
 async def test_hook_prepare_jinja2_environment(app_client):
+    app_client.ds._HELLO = "HI"
     template = app_client.ds.jinja_env.from_string(
-        "Hello there, {{ a|format_numeric }}", {"a": 3412341}
+        "Hello there, {{ a|format_numeric }}, {{ a|to_hello }}", {"a": 3412341}
     )
     rendered = await app_client.ds.render_template(template)
-    assert "Hello there, 3,412,341" == rendered
+    assert "Hello there, 3,412,341, HI" == rendered
 
 
 def test_hook_publish_subcommand():