Added the ability to specify a JSON decoder

Author: switchtrue

Diff for: flask_graphql/graphqlview.py

@@ -34,6 +34,7 @@ class GraphQLView(View):
     middleware = None
     batch = False
     json_encoder = None
+    json_decoder = None
 
     methods = ['GET', 'POST', 'PUT', 'DELETE']
 
@@ -156,7 +157,7 @@ def parse_body(self, request):
 
         elif content_type == 'application/json':
             try:
-                request_json = json.loads(request.data.decode('utf8'))
+                request_json = json.loads(request.data.decode('utf8'), cls=self.json_decoder)
                 if self.batch:
                     assert isinstance(request_json, list)
                 else:

Diff for: tests/encoder.py

@@ -1,6 +1,12 @@
-from json import JSONEncoder
+from json import JSONEncoder, JSONDecoder
+from json.decoder import WHITESPACE
 
 
 class TestJSONEncoder(JSONEncoder):
     def encode(self, o):
         return 'TESTSTRING'
+
+
+class TestJSONDecoder(JSONDecoder):
+    def decode(self, s, _w=WHITESPACE.match):
+        return {'query': '{test}'}

Diff for: tests/test_graphqlview.py

@@ -12,7 +12,7 @@
     from urllib.parse import urlencode
 
 from .app import create_app
-from .encoder import TestJSONEncoder
+from .encoder import TestJSONEncoder, TestJSONDecoder
 from flask import url_for
 
 
@@ -541,3 +541,15 @@ def test_custom_encoder(client):
 
     # TestJSONEncoder just encodes everything to 'TESTSTRING'
     assert response.data.decode() == 'TESTSTRING'
+
+
+@pytest.mark.parametrize('app', [create_app(json_decoder=TestJSONDecoder)])
+def test_custom_decoder(client):
+    # The submitted data here of 'TEST' is clearly not valid JSON. The TestJSONDecoder will
+    # decode this into valid JSON with a valid gql query.
+    response = client.post(url_string(), data='TEST', content_type='application/json')
+
+    assert response.status_code == 200
+    assert response_json(response) == {
+        'data': {'test': "Hello World"}
+    }