Adds support for content encoding, namely gip and deflate

1 files changed, 43 insertions, 0 deletions

diff --git a/libmproxy/encoding.py b/libmproxy/encoding.py
new file mode 100644
index 00000000..f280ed9f
--- /dev/null
+++ b/libmproxy/encoding.py
@@ -0,0 +1,43 @@
+"""
+    Utility functions for decoding response bodies.
+"""
+import cStringIO
+import gzip, zlib
+
+__ALL__ = ["ENCODINGS"]
+
+ENCODINGS = set(["identity", "gzip", "deflate"])
+
+def decode(encoding, content):
+    encoding_map = {
+        "identity": decode_identity,
+        "gzip": decode_gzip,
+        "deflate": decode_deflate,
+    }
+
+    return encoding_map.get(encoding, decode_identity)(content)
+
+def decode_identity(content):
+    """
+        Returns content unchanged. Identity is the default value of
+        Accept-Encoding headers.
+    """
+    return content
+
+def decode_gzip(content):
+    gfile = gzip.GzipFile(fileobj=cStringIO.StringIO(content))
+    return gfile.read()
+
+def decode_deflate(content):
+    """
+        Returns decompress data for DEFLATE. Some servers may respond with
+        compressed data without a zlib header or checksum. An undocumented
+        feature of zlib permits the lenient decompression of data missing both
+        values.
+
+        http://bugs.python.org/issue5784
+    """
+    try:
+        return zlib.decompress(content)
+    except zlib.error:
+        return zlib.decompress(content, -15)
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