Cleanup response.json() method (#2911)

Co-authored-by: Kar Petrosyan <92274156+karpetrosyan@users.noreply.github.com>

httpx/_models.py

@@ -43,7 +43,6 @@
 )
 from ._urls import URL
 from ._utils import (
-    guess_json_utf,
     is_known_encoding,
     normalize_header_key,
     normalize_header_value,
@@ -759,11 +758,7 @@ def raise_for_status(self) -> "Response":
         raise HTTPStatusError(message, request=request, response=self)
 
     def json(self, **kwargs: typing.Any) -> typing.Any:
-        if self.charset_encoding is None and self.content and len(self.content) > 3:
-            encoding = guess_json_utf(self.content)
-            if encoding is not None:
-                return jsonlib.loads(self.content.decode(encoding), **kwargs)
-        return jsonlib.loads(self.text, **kwargs)
+        return jsonlib.loads(self.content, **kwargs)
 
     @property
     def cookies(self) -> "Cookies":

httpx/_utils.py

@@ -91,41 +91,6 @@ def replacer(match: typing.Match[str]) -> str:
     return f'{name}="{value}"'.encode()
 
 
-# Null bytes; no need to recreate these on each call to guess_json_utf
-_null = b"\x00"
-_null2 = _null * 2
-_null3 = _null * 3
-
-
-def guess_json_utf(data: bytes) -> typing.Optional[str]:
-    # JSON always starts with two ASCII characters, so detection is as
-    # easy as counting the nulls and from their location and count
-    # determine the encoding. Also detect a BOM, if present.
-    sample = data[:4]
-    if sample in (codecs.BOM_UTF32_LE, codecs.BOM_UTF32_BE):
-        return "utf-32"  # BOM included
-    if sample[:3] == codecs.BOM_UTF8:
-        return "utf-8-sig"  # BOM included, MS style (discouraged)
-    if sample[:2] in (codecs.BOM_UTF16_LE, codecs.BOM_UTF16_BE):
-        return "utf-16"  # BOM included
-    nullcount = sample.count(_null)
-    if nullcount == 0:
-        return "utf-8"
-    if nullcount == 2:
-        if sample[::2] == _null2:  # 1st and 3rd are null
-            return "utf-16-be"
-        if sample[1::2] == _null2:  # 2nd and 4th are null
-            return "utf-16-le"
-        # Did not detect 2 valid UTF-16 ascii-range characters
-    if nullcount == 3:
-        if sample[:3] == _null3:
-            return "utf-32-be"
-        if sample[1:] == _null3:
-            return "utf-32-le"
-        # Did not detect a valid UTF-32 ascii-range character
-    return None
-
-
 def get_ca_bundle_from_env() -> typing.Optional[str]:
     if "SSL_CERT_FILE" in os.environ:
         ssl_file = Path(os.environ["SSL_CERT_FILE"])

tests/test_utils.py

@@ -1,3 +1,4 @@
+import json
 import logging
 import os
 import random
@@ -10,7 +11,6 @@
     URLPattern,
     get_ca_bundle_from_env,
     get_environment_proxies,
-    guess_json_utf,
     is_https_redirect,
     obfuscate_sensitive_headers,
     parse_header_links,
@@ -34,12 +34,16 @@
     ),
 )
 def test_encoded(encoding):
-    data = "{}".encode(encoding)
-    assert guess_json_utf(data) == encoding
+    content = '{"abc": 123}'.encode(encoding)
+    response = httpx.Response(200, content=content)
+    assert response.json() == {"abc": 123}
 
 
 def test_bad_utf_like_encoding():
-    assert guess_json_utf(b"\x00\x00\x00\x00") is None
+    content = b"\x00\x00\x00\x00"
+    response = httpx.Response(200, content=content)
+    with pytest.raises(json.decoder.JSONDecodeError):
+        response.json()
 
 
 @pytest.mark.parametrize(
@@ -52,8 +56,9 @@ def test_bad_utf_like_encoding():
     ),
 )
 def test_guess_by_bom(encoding, expected):
-    data = "\ufeff{}".encode(encoding)
-    assert guess_json_utf(data) == expected
+    content = '\ufeff{"abc": 123}'.encode(encoding)
+    response = httpx.Response(200, content=content)
+    assert response.json() == {"abc": 123}
 
 
 @pytest.mark.parametrize(