uaiohttpclient: Implement support for chunked transfer encoding.

Chunked T-E is mandatory for HTTP/1.1, and thus prerequisite for supporting
it.

uaiohttpclient/uaiohttpclient.py

@@ -13,6 +13,35 @@ class ClientResponse:
         return "<ClientResponse %d %s>" % (self.status, self.headers)
 
 
+class ChunkedClientResponse(ClientResponse):
+
+    def __init__(self, reader):
+        self.content = reader
+        self.chunk_size = 0
+
+    def read(self, sz=4*1024*1024):
+        if self.chunk_size == 0:
+            l = yield from self.content.readline()
+            #print("chunk line:", l)
+            l = l.split(b";", 1)[0]
+            self.chunk_size = int(l, 16)
+            #print("chunk size:", self.chunk_size)
+            if self.chunk_size == 0:
+                # End of message
+                sep = yield from self.content.read(2)
+                assert sep == b"\r\n"
+                return b''
+        data = yield from self.content.read(min(sz, self.chunk_size))
+        self.chunk_size -= len(data)
+        if self.chunk_size == 0:
+            sep = yield from self.content.read(2)
+            assert sep == b"\r\n"
+        return data
+
+    def __repr__(self):
+        return "<ChunkedClientResponse %d %s>" % (self.status, self.headers)
+
+
 def request_raw(method, url):
     try:
         proto, dummy, host, path = url.split("/", 3)
@@ -31,16 +60,23 @@ def request_raw(method, url):
 
 def request(method, url):
     reader = yield from request_raw(method, url)
-    resp = ClientResponse(reader)
     headers = []
     sline = yield from reader.readline()
     protover, st, msg = sline.split(None, 2)
-    resp.status = int(st)
+    chunked = False
     while True:
         line = yield from reader.readline()
         if not line or line == b"\r\n":
             break
         headers.append(line)
+        if line.startswith(b"Transfer-Encoding:"):
+            if b"chunked" in line:
+                chunked = True
 
+    if chunked:
+        resp = ChunkedClientResponse(reader)
+    else:
+        resp = ClientResponse(reader)
+    resp.status = int(st)
     resp.headers = headers
     return resp