From a837230320378d629ba9f25960b1dfd25c892ad9 Mon Sep 17 00:00:00 2001
From: Thomas Kriechbaumer <thomas@kriechbaumer.name>
Date: Sat, 1 Aug 2015 10:39:14 +0200
Subject: move code from mitmproxy to netlib

---
 netlib/encoding.py | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 netlib/encoding.py

(limited to 'netlib/encoding.py')

diff --git a/netlib/encoding.py b/netlib/encoding.py
new file mode 100644
index 00000000..f107eb5f
--- /dev/null
+++ b/netlib/encoding.py
@@ -0,0 +1,82 @@
+"""
+    Utility functions for decoding response bodies.
+"""
+from __future__ import absolute_import
+import cStringIO
+import gzip
+import zlib
+
+__ALL__ = ["ENCODINGS"]
+
+ENCODINGS = set(["identity", "gzip", "deflate"])
+
+
+def decode(e, content):
+    encoding_map = {
+        "identity": identity,
+        "gzip": decode_gzip,
+        "deflate": decode_deflate,
+    }
+    if e not in encoding_map:
+        return None
+    return encoding_map[e](content)
+
+
+def encode(e, content):
+    encoding_map = {
+        "identity": identity,
+        "gzip": encode_gzip,
+        "deflate": encode_deflate,
+    }
+    if e not in encoding_map:
+        return None
+    return encoding_map[e](content)
+
+
+def 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))
+    try:
+        return gfile.read()
+    except (IOError, EOFError):
+        return None
+
+
+def encode_gzip(content):
+    s = cStringIO.StringIO()
+    gf = gzip.GzipFile(fileobj=s, mode='wb')
+    gf.write(content)
+    gf.close()
+    return s.getvalue()
+
+
+def decode_deflate(content):
+    """
+        Returns decompressed 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:
+        try:
+            return zlib.decompress(content)
+        except zlib.error:
+            return zlib.decompress(content, -15)
+    except zlib.error:
+        return None
+
+
+def encode_deflate(content):
+    """
+        Returns compressed content, always including zlib header and checksum.
+    """
+    return zlib.compress(content)
-- 
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