Refine encoding support

- Push decoding down into the LRU cache
- Cope gracefully with corrupted data and incorrect encoding headers

libmproxy/console.py

@@ -306,7 +306,8 @@ class ConnectionView(WWrap):
             else:
                 e = "identity"
             return self.master._cached_conn_text(
-                        encoding.decode(e, conn.content),
+                        e,
+                        conn.content,
                         tuple([tuple(i) for i in conn.headers.lst]),
                         viewmode
                     )
@@ -965,7 +966,10 @@ class ConsoleMaster(flow.FlowMaster):
         return self._view_conn_raw(content, txt)
 
     @utils.LRUCache(20)
-    def _cached_conn_text(self, content, hdrItems, viewmode):
+    def _cached_conn_text(self, e, rawcontent, hdrItems, viewmode):
+        content = encoding.decode(e, rawcontent)
+        if content is None:
+            content = rawcontent
         hdr = []
         hdr.extend(
             format_keyvals(

libmproxy/encoding.py

@@ -14,7 +14,6 @@ def decode(encoding, content):
         "gzip": decode_gzip,
         "deflate": decode_deflate,
     }
-
     return encoding_map.get(encoding, decode_identity)(content)
 
 def decode_identity(content):
@@ -26,7 +25,10 @@ def decode_identity(content):
 
 def decode_gzip(content):
     gfile = gzip.GzipFile(fileobj=cStringIO.StringIO(content))
-    return gfile.read()
+    try:
+        return gfile.read()
+    except IOError:
+        return None
 
 def decode_deflate(content):
     """
@@ -38,6 +40,9 @@ def decode_deflate(content):
         http://bugs.python.org/issue5784
     """
     try:
-        return zlib.decompress(content)
+        try:
+            return zlib.decompress(content)
+        except zlib.error:
+            return zlib.decompress(content, -15)
     except zlib.error:
-        return zlib.decompress(content, -15)
+        return None

test/test_encoding.py

@@ -18,11 +18,13 @@ class udecode_gzip(libpry.AutoTree):
         gf.write('string')
         gf.close()
         assert 'string' == encoding.decode('gzip', s.getvalue())
+        assert None == encoding.decode("gzip", "bogus")
 
 class udecode_deflate(libpry.AutoTree):
     def test_simple(self):
         assert 'string' == encoding.decode('deflate', zlib.compress('string'))
         assert 'string' == encoding.decode('deflate', zlib.compress('string')[2:-4])
+        assert None == encoding.decode("deflate", "bogus")
 
 tests = [
     udecode_identity(),