Clean up response interface

diff --git a/httpcore/models.py b/httpcore/models.py
index 97e18dc56c58b81ca4ae4fb0d67d9226ec1803de..2e01dab58f5389254ebb19f474e57a0389c7e44d 100644 (file)
--- a/httpcore/models.py
+++ b/httpcore/models.py
@@ -324,20 +324,6 @@ class Response:
         self.is_closed = False
         self.is_streamed = False
 
-        decoders = []  # type: typing.List[Decoder]
-        value = self.headers.get("content-encoding", "identity")
-        for part in value.split(","):
-            part = part.strip().lower()
-            decoder_cls = SUPPORTED_DECODERS[part]
-            decoders.append(decoder_cls())
-
-        if len(decoders) == 0:
-            self.decoder = IdentityDecoder()  # type: Decoder
-        elif len(decoders) == 1:
-            self.decoder = decoders[0]
-        else:
-            self.decoder = MultiDecoder(decoders)
-
         if isinstance(body, bytes):
             self.is_closed = True
             self.body = self.decoder.decode(body) + self.decoder.flush()
@@ -350,8 +336,36 @@ class Response:
 
     @property
     def url(self) -> typing.Optional[URL]:
+        """
+        Returns the URL for which the request was made.
+
+        Requires that `request` was provided when instantiating the response.
+        """
         return None if self.request is None else self.request.url
 
+    @property
+    def decoder(self) -> Decoder:
+        """
+        Returns a decoder instance which can be used to decode the raw byte
+        content, depending on the Content-Encoding used in the response.
+        """
+        if not hasattr(self, "_decoder"):
+            decoders = []  # type: typing.List[Decoder]
+            value = self.headers.get("content-encoding", "identity")
+            for part in value.split(","):
+                part = part.strip().lower()
+                decoder_cls = SUPPORTED_DECODERS[part]
+                decoders.append(decoder_cls())
+
+            if len(decoders) == 1:
+                self._decoder = decoders[0]
+            elif len(decoders) > 1:
+                self._decoder = MultiDecoder(decoders)
+            else:
+                self._decoder = IdentityDecoder()
+
+        return self._decoder
+
     async def read(self) -> bytes:
         """
         Read and return the response content.