looser Content-Type header checking for application/json (#101)

jivago/wsgi/request/json_serialization_filter.py

@@ -1,6 +1,9 @@
 import json
+from typing import Optional
 
 from jivago.lang.annotations import Override
+from jivago.lang.nullable import Nullable
+from jivago.lang.stream import Stream
 from jivago.wsgi.filter.filter import Filter
 from jivago.wsgi.filter.filter_chain import FilterChain
 from jivago.wsgi.request.request import Request
@@ -11,11 +14,17 @@ class JsonSerializationFilter(Filter):
 
     @Override
     def doFilter(self, request: Request, response: Response, chain: FilterChain):
-        if request.headers['Content-Type'] == 'application/json' and len(request.body) > 0:
+        if is_application_json(request.headers['Content-Type']) and len(request.body) > 0:
             request.body = json.loads(request.body)
 
         chain.doFilter(request, response)
 
         if isinstance(response.body, dict) or isinstance(response.body, list):
             response.body = json.dumps(response.body)
             response.headers['Content-Type'] = 'application/json'
+
+
+def is_application_json(content_type: Optional[str]) -> bool:
+    return Nullable(content_type) \
+        .map(lambda x: "application/json" in x) \
+        .orElse(False)

test/wsgi/filter/system_filters/test_json_serialization_filter.py

@@ -43,6 +43,27 @@ def test_givenSerializable_whenApplyingFilter_thenSetContentTypeToApplicationJso
     def test_givenApplicationJsonHeaderWithEmptyBody_whenApplyingFilter_thenDoNotDeserializeTheEmptyString(self):
         request = RequestBuilder().headers({"Content-Type": "application/json"}).body("").method("POST").build()
 
-        self.filter.doFilter(A_REQUEST, ResponseBuilder().build(), self.filterChainMock)
+        self.filter.doFilter(request, ResponseBuilder().build(), self.filterChainMock)
 
         self.assertEqual("", request.body)
+
+    def test_givenMultipleContentTypeDirectives_whenApplyingFilter_thenMatchOnMediaType(self):
+        """https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type"""
+        request = RequestBuilder() \
+            .headers({"Content-Type": "application/json; charset=utf-8"}) \
+            .body('{"name": "bar"}') \
+            .build()
+
+        self.filter.doFilter(request, ResponseBuilder().build(), self.filterChainMock)
+
+        self.assertEqual({"name": "bar"}, request.body)
+
+    def test_givenTrailingSemiColonInContentType_whenApplyingFilter_thenMatchAnyway(self):
+        request = RequestBuilder() \
+            .headers({"Content-Type": "application/json; "}) \
+            .body('{"name": "bar"}') \
+            .build()
+
+        self.filter.doFilter(request, ResponseBuilder().build(), self.filterChainMock)
+
+        self.assertEqual({"name": "bar"}, request.body)