Added GraphiQL template injection

Author: lucasrcosta

Diff for: README.md

@@ -23,8 +23,8 @@ This will add `/graphql` and `/graphiql` endpoints to your app.
  * `root_value`: The `root_value` you want to provide to `executor.execute`.
  * `pretty`: Whether or not you want the response to be pretty printed JSON.
  * `executor`: The `Executor` that you want to use to execute queries.
- * `graphiql`: If `True`, may present [GraphiQL](https://github.com/graphql/graphiql) when loaded directly
-    from a browser (a useful tool for debugging and exploration).
+ * `graphiql`: If `True`, may present [GraphiQL](https://github.com/graphql/graphiql) when loaded directly from a browser (a useful tool for debugging and exploration).
+ * `graphiql_template`: Inject a Jinja template string to customize GraphiQL.
 
 You can also subclass `GraphQLView` and overwrite `get_root_value(self, request)` to have a dynamic root value
 per request.

Diff for: flask_graphql/graphqlview.py

@@ -30,6 +30,7 @@ class GraphQLView(View):
     pretty = False
     graphiql = False
     graphiql_version = None
+    graphiql_template = None
     middleware = None
 
     methods = ['GET', 'POST', 'PUT', 'DELETE']
@@ -92,6 +93,7 @@ def dispatch_request(self):
             if show_graphiql:
                 return render_graphiql(
                     graphiql_version=self.graphiql_version,
+                    graphiql_template=self.graphiql_template,
                     query=query,
                     variables=variables,
                     operation_name=operation_name,

Diff for: flask_graphql/render_graphiql.py

@@ -123,8 +123,9 @@
 </html>'''
 
 
-def render_graphiql(graphiql_version=None, **kwargs):
-    if not graphiql_version:
-        graphiql_version = GRAPHIQL_VERSION
+def render_graphiql(graphiql_version=None, graphiql_template=None, **kwargs):
+    graphiql_version = graphiql_version or GRAPHIQL_VERSION
+    template = graphiql_template or TEMPLATE
 
-    return render_template_string(TEMPLATE, graphiql_version=graphiql_version, **kwargs)
+    return render_template_string(
+        template, graphiql_version=graphiql_version, **kwargs)