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vcr/filters.py

@@ -16,9 +16,38 @@ except ImportError:
         brotli = None
 
 
-AVAILABLE_DECOMPRESSORS = {"gzip", "deflate"}
+def decompress_deflate(body):
+    try:
+        return zlib.decompress(body)
+    except zlib.error:
+        # Assume the response was already decompressed
+        return body
+
+
+def decompress_gzip(body):
+    # To (de-)compress gzip format, use wbits = zlib.MAX_WBITS | 16.
+    try:
+        return zlib.decompress(body, zlib.MAX_WBITS | 16)
+    except zlib.error:
+        # Assume the response was already decompressed
+        return body
+
+
+AVAILABLE_DECOMPRESSORS = {
+    "deflate": decompress_deflate,
+    "gzip": decompress_gzip,
+}
+
 if brotli is not None:
-    AVAILABLE_DECOMPRESSORS.add("br")
+
+    def decompress_brotli(body):
+        try:
+            return brotli.decompress(body)
+        except brotli.error:
+            # Assume the response was already decompressed
+            return body
+
+    AVAILABLE_DECOMPRESSORS["br"] = decompress_brotli
 
 
 def replace_headers(request, replacements):
@@ -157,44 +186,22 @@ def decode_response(response):
       3. update content-length header to decompressed length
     """
 
-    def is_decompressable(headers):
-        encoding = headers.get("content-encoding", [])
-        return encoding and encoding[0] in AVAILABLE_DECOMPRESSORS
-
-    def decompress_body(body, encoding):
-        """Returns decompressed body according to encoding using zlib.
-        to (de-)compress gzip format, use wbits = zlib.MAX_WBITS | 16
-        """
-        if not body:
-            return ""
-        if encoding == "gzip":
-            try:
-                return zlib.decompress(body, zlib.MAX_WBITS | 16)
-            except zlib.error:
-                return body  # assumes that the data was already decompressed
-        elif encoding == 'deflate':
-            try:
-                return zlib.decompress(body)
-            except zlib.error:
-                return body  # assumes that the data was already decompressed
-        else:  # encoding == 'br'
-            try:
-                return brotli.decompress(body)
-            except brotli.error:
-                return body  # assumes that the data was already decompressed
-
-
     # Deepcopy here in case `headers` contain objects that could
     # be mutated by a shallow copy and corrupt the real response.
     response = copy.deepcopy(response)
     headers = CaseInsensitiveDict(response["headers"])
-    if is_decompressable(headers):
-        encoding = headers["content-encoding"][0]
-        headers["content-encoding"].remove(encoding)
+    content_encoding = headers.get("content-encoding")
+    if not content_encoding:
+        return response
+    decompressor = AVAILABLE_DECOMPRESSORS.get(content_encoding[0])
+    if not decompressor:
+        return response
+
+    headers["content-encoding"].remove(content_encoding[0])
     if not headers["content-encoding"]:
         del headers["content-encoding"]
 
-        new_body = decompress_body(response["body"]["string"], encoding)
+    new_body = decompressor(response["body"]["string"])
     response["body"]["string"] = new_body
     headers["content-length"] = [str(len(new_body))]
     response["headers"] = dict(headers)