Don't allow canned write queries on immutable DBs, closes #1728

datasette/templates/query.html

@@ -28,6 +28,10 @@
 
 {% block content %}
 
+{% if canned_write and db_is_immutable %}
+    <p class="message-error">This query cannot be executed because the database is immutable.</p>
+{% endif %}
+
 <h1 style="padding-left: 10px; border-left: 10px solid #{{ database_color(database) }}">{{ metadata.title or database }}{% if canned_query and not metadata.title %}: {{ canned_query }}{% endif %}{% if private %} 🔒{% endif %}</h1>
 
 {% block description_source_license %}{% include "_description_source_license.html" %}{% endblock %}
@@ -61,7 +65,7 @@
     <p>
         {% if not hide_sql %}<button id="sql-format" type="button" hidden>Format SQL</button>{% endif %}
         {% if canned_write %}<input type="hidden" name="csrftoken" value="{{ csrftoken() }}">{% endif %}
-        <input type="submit" value="Run SQL">
+        <input type="submit" value="Run SQL"{% if canned_write and db_is_immutable %} disabled{% endif %}>
         {{ show_hide_hidden }}
         {% if canned_query and edit_sql_url %}<a href="{{ edit_sql_url }}" class="canned-query-edit-sql">Edit SQL</a>{% endif %}
     </p>

datasette/views/database.py

@@ -273,6 +273,9 @@ class QueryView(DataView):
         # Execute query - as write or as read
         if write:
             if request.method == "POST":
+                # If database is immutable, return an error
+                if not db.is_mutable:
+                    raise Forbidden("Database is immutable")
                 body = await request.post_body()
                 body = body.decode("utf-8").strip()
                 if body.startswith("{") and body.endswith("}"):
@@ -326,6 +329,7 @@ class QueryView(DataView):
                 async def extra_template():
                     return {
                         "request": request,
+                        "db_is_immutable": not db.is_mutable,
                         "path_with_added_args": path_with_added_args,
                         "path_with_removed_args": path_with_removed_args,
                         "named_parameter_values": named_parameter_values,

tests/test_canned_queries.py

@@ -53,6 +53,26 @@ def canned_write_client(tmpdir):
         yield client
 
 
+@pytest.fixture
+def canned_write_immutable_client():
+    with make_app_client(
+        is_immutable=True,
+        metadata={
+            "databases": {
+                "fixtures": {
+                    "queries": {
+                        "add": {
+                            "sql": "insert into sortable (text) values (:text)",
+                            "write": True,
+                        },
+                    }
+                }
+            }
+        },
+    ) as client:
+        yield client
+
+
 def test_canned_query_with_named_parameter(app_client):
     response = app_client.get("/fixtures/neighborhood_search.json?text=town")
     assert [
@@ -373,3 +393,23 @@ def test_canned_write_custom_template(canned_write_client):
         response.headers["link"]
         == 'http://localhost/data/update_name.json; rel="alternate"; type="application/json+datasette"'
     )
+
+
+def test_canned_write_query_disabled_for_immutable_database(
+    canned_write_immutable_client,
+):
+    response = canned_write_immutable_client.get("/fixtures/add")
+    assert response.status == 200
+    assert (
+        "This query cannot be executed because the database is immutable."
+        in response.text
+    )
+    assert '<input type="submit" value="Run SQL" disabled>' in response.text
+    # Submitting form should get a forbidden error
+    response = canned_write_immutable_client.post(
+        "/fixtures/add",
+        {"text": "text"},
+        csrftoken_from=True,
+    )
+    assert response.status == 403
+    assert "Database is immutable" in response.text