Expose extra_template_vars in _contex=1, refs #693

datasette/app.py

@@ -14,6 +14,7 @@ from pathlib import Path
 
 import click
 from markupsafe import Markup
+import jinja2
 from jinja2 import ChoiceLoader, Environment, FileSystemLoader, PrefixLoader, escape
 from jinja2.environment import Template
 import uvicorn
@@ -612,6 +613,11 @@ class Datasette:
             },
             **extra_template_vars,
         }
+        if request and request.args.get("_context") and self.config("template_debug"):
+            return "<pre>{}</pre>".format(
+                jinja2.escape(json.dumps(template_context, default=repr, indent=4))
+            )
+
         return await template.render_async(template_context)
 
     def _asset_urls(self, key, template, context):

datasette/views/base.py

@@ -6,7 +6,6 @@ import re
 import time
 import urllib
 
-import jinja2
 import pint
 
 from datasette import __version__
@@ -82,16 +81,6 @@ class BaseView(AsgiView):
                 "database_color": self.database_color,
             },
         }
-        if (
-            request
-            and request.args.get("_context")
-            and self.ds.config("template_debug")
-        ):
-            return Response.html(
-                "<pre>{}</pre>".format(
-                    jinja2.escape(json.dumps(template_context, default=repr, indent=4))
-                )
-            )
         return Response.html(
             await self.ds.render_template(
                 template, template_context, request=request, view_name=self.name

tests/test_html.py

@@ -1097,6 +1097,14 @@ def test_config_template_debug_off(app_client):
     assert not response.text.startswith("<pre>{")
 
 
+def test_debug_context_includes_extra_template_vars():
+    # https://github.com/simonw/datasette/issues/693
+    for client in make_app_client(config={"template_debug": True}):
+        response = client.get("/fixtures/facetable?_context=1")
+        # scope_path is added by PLUGIN1
+        assert "scope_path" in response.text
+
+
 def test_metadata_sort(app_client):
     response = app_client.get("/fixtures/facet_cities")
     assert response.status == 200