🔧 relax strictness around Response.json(...) that checked Content-Type prior to decoding

We may review that behavior in a future major version.

Author: Ousret

HISTORY.md

@@ -1,6 +1,14 @@
 Release History
 ===============
 
+3.12.3 (2025-01-28)
+-------------------
+
+**Changed**
+- Relaxed strict compliance on JSON parsing. We brought strict compliance into Niquests, a response
+  must explicitly set `Content-Type: application/json` or alike prior to attempt parsing the JSON string.
+  We decided to relax that constraint as old and bad-behaving server may send JSON with missing or broken Content-Type.
+
 3.12.2 (2025-01-22)
 -------------------
 

src/niquests/models.py

@@ -1444,8 +1444,8 @@ def json(self, **kwargs: typing.Any) -> typing.Any:
             contain valid json or if content-type is not about json.
         """
 
-        if not self.content or "json" not in self.headers.get("content-type", "").lower():
-            raise RequestsJSONDecodeError("response content is not JSON", self.text or "", 0)
+        if not self.content:
+            raise RequestsJSONDecodeError("response content is not JSON", "", 0)
 
         if not self.encoding:
             # No encoding set. JSON RFC 4627 section 3 states we should expect
@@ -1467,10 +1467,13 @@ def json(self, **kwargs: typing.Any) -> typing.Any:
             ).best()
 
             if encoding_guess is not None:
+                self.encoding = encoding_guess.encoding
                 try:
                     return _json.loads(str(encoding_guess), **kwargs)
                 except _json.JSONDecodeError as e:
                     raise RequestsJSONDecodeError(e.msg, e.doc, e.pos)
+            else:
+                self.encoding = "utf-8"  # try Unicode anyway[...]
 
         plain_content = self.text
 
@@ -1813,8 +1816,8 @@ async def text(self) -> str | None:  # type: ignore[override]
     async def json(self, **kwargs: typing.Any) -> typing.Any:  # type: ignore[override]
         content = await self.content
 
-        if not content or "json" not in self.headers.get("content-type", "").lower():
-            raise RequestsJSONDecodeError("response content is not JSON", await self.text or "", 0)
+        if not content:
+            raise RequestsJSONDecodeError("response content is not JSON", "", 0)
 
         if not self.encoding:
             # No encoding set. JSON RFC 4627 section 3 states we should expect
@@ -1836,15 +1839,18 @@ async def json(self, **kwargs: typing.Any) -> typing.Any:  # type: ignore[overri
             ).best()
 
             if encoding_guess is not None:
+                self.encoding = encoding_guess.encoding
                 try:
                     return _json.loads(str(encoding_guess), **kwargs)
                 except _json.JSONDecodeError as e:
                     raise RequestsJSONDecodeError(e.msg, e.doc, e.pos)
+            else:
+                self.encoding = "utf-8"
 
         plain_content = await self.text
 
         if plain_content is None:
-            raise RequestsJSONDecodeError("response cannot lead to decodable JSON", "", 0)
+            raise RequestsJSONDecodeError("response cannot lead to unserializable JSON", "", 0)
 
         try:
             return _json.loads(plain_content, **kwargs)