X-Git-Url: https://jfr.im/git/z_archive/twitter.git/blobdiff_plain/e28a1da9ea6df9761811e101e9e475268a87ac76..3f6ca83dfc697b71974d2fa3b10b4e68c4d4c621:/twitter/stream.py

diff --git a/twitter/stream.py b/twitter/stream.py
index fa332cf..6ecc49e 100644
--- a/twitter/stream.py
+++ b/twitter/stream.py
@@ -12,32 +12,42 @@ import sys, select, time
 
 from .api import TwitterCall, wrap_response, TwitterHTTPError
 
-def recv_chunk(sock):
-    buf = sock.recv(10)  # Scan for an up to a 4GiB chunk size (0xffffffff).
-    if buf:
-        crlf = buf.find(b'\r\n')  # Find the HTTP chunk size.
-        if crlf > 0:
-            remaining = int(buf[:crlf], 16)  # Decode the chunk size.
-            chunk = bytearray(remaining)  # Create the chunk buffer.
-
-            start = crlf + 2  # Add in the length of the header's CRLF pair.
-            end = len(buf) - start
-
-            chunk[:end] = buf[start:]
-            chunk[end:] = sock.recv(remaining - end)
-
+python27_3 = sys.version_info >= (2, 7)
+def recv_chunk(sock): # -> bytearray:
+
+    header = sock.recv(8)  # Scan for an up to 16MiB chunk size (0xffffff).
+    crlf = header.find(b'\r\n')  # Find the HTTP chunk size.
+
+    if crlf > 0:  # If there is a length, then process it
+
+        size = int(header[:crlf], 16)  # Decode the chunk size. Rarely exceeds 8KiB.
+        chunk = bytearray(size)
+        start = crlf + 2  # Add in the length of the header's CRLF pair.
+
+        if size <= 3:  # E.g. an HTTP chunk with just a keep-alive delimiter or end of stream (0).
+            chunk[:size] = header[start:start + size]
+        # There are several edge cases (size == [4-6]) as the chunk size exceeds the length
+        # of the initial read of 8 bytes. With Twitter, these do not, in practice, occur. The
+        # shortest JSON message starts with '{"limit":{'. Hence, it exceeds in size the edge cases
+        # and eliminates the need to address them.
+        else:  # There is more to read in the chunk.
+            end = len(header) - start
+            chunk[:end] = header[start:]
+            if python27_3:  # When possible, use less memory by reading directly into the buffer.
+                buffer = memoryview(chunk)[end:]  # Create a view into the bytearray to hold the rest of the chunk.
+                sock.recv_into(buffer)
+            else:  # less efficient for python2.6 compatibility
+                chunk[end:] = sock.recv(max(0, size - end))
             sock.recv(2)  # Read the trailing CRLF pair. Throw it away.
 
-            return chunk
-    return b''
+        return chunk
 
-##  recv_chunk()
+    return bytearray()
 
 
 class TwitterJSONIter(object):
 
     def __init__(self, handle, uri, arg_data, block=True, timeout=None):
-        self.decoder = json.JSONDecoder()
         self.handle = handle
         self.uri = uri
         self.arg_data = arg_data
@@ -46,51 +56,44 @@ class TwitterJSONIter(object):
 
 
     def __iter__(self):
-        if sys.version_info >= (3, 0):
-            sock = self.handle.fp.raw._sock
-        else:
-            sock = self.handle.fp._sock.fp._sock
+        sock = self.handle.fp.raw._sock if sys.version_info >= (3, 0) else self.handle.fp._sock.fp._sock
         sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
-        if not self.block or self.timeout:
-            sock.setblocking(False)
-        buf = b''
+        sock.setblocking(self.block and not self.timeout)
+        buf = ''
+        json_decoder = json.JSONDecoder()
         timer = time.time()
         while True:
             try:
-                utf8_buf = buf.decode('utf-8').lstrip()
-                res, ptr = self.decoder.raw_decode(utf8_buf)
-                buf = utf8_buf[ptr:].encode('utf-8')
+                buf = buf.lstrip()
+                res, ptr = json_decoder.raw_decode(buf)
+                buf = buf[ptr:]
                 yield wrap_response(res, self.handle.headers)
-                timer = time.time()
                 continue
             except ValueError as e:
-                if self.block:
-                    pass
-                else:
-                    yield None
-            # this is a non-blocking read (ie, it will return if any data is available)
+                if self.block: pass
+                else: yield None
             try:
-                if self.timeout:
+                buf = buf.lstrip()  # Remove any keep-alive delimiters to detect hangups.
+                if self.timeout and not buf:  # This is a non-blocking read.
                     ready_to_read = select.select([sock], [], [], self.timeout)
-                    if ready_to_read[0]:
-                        buf += recv_chunk(sock)
-                        if time.time() - timer > self.timeout:
-                            yield {"timeout":True}
-                    else:
-                        yield {"timeout":True}
-                else:
-                    buf += recv_chunk(sock)
+                    if not ready_to_read[0] and time.time() - timer > self.timeout:
+                        yield {'timeout': True}
+                        continue
+                timer = time.time()
+                buf += recv_chunk(sock).decode('utf-8')
+                if not buf:
+                    yield {'hangup': True}
+                    break
             except SSLError as e:
-                if (not self.block or self.timeout) and (e.errno == 2):
-                    # Apparently this means there was nothing in the socket buf
-                    pass
-                else:
-                    raise
-            except urllib_error.HTTPError as e:
-                raise TwitterHTTPError(e, self.uri, 'json', self.arg_data)
+                # Error from a non-blocking read of an empty buffer.
+                if (not self.block or self.timeout) and (e.errno == 2): pass
+                else: raise
 
 def handle_stream_response(req, uri, arg_data, block, timeout=None):
-    handle = urllib_request.urlopen(req,)
+    try:
+        handle = urllib_request.urlopen(req,)
+    except urllib_error.HTTPError as e:
+        raise TwitterHTTPError(e, uri, 'json', arg_data)
     return iter(TwitterJSONIter(handle, uri, arg_data, block, timeout=timeout))
 
 class TwitterStreamCallWithTimeout(TwitterCall):