h2spy.py

h2spy.py

@@ -0,0 +1,130 @@
+import socket
+import ssl
+import enum
+try:
+    import hyperframe.frame
+except:
+    exit('install "hyperframe" from pip')
+try:
+    import hpack
+except:
+    exit('install "hpack" from pip')
+
+MAGIC = b'PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n'
+
+
+class ErrorCode(enum.Enum):
+    NO_ERROR = 0
+    PROTOCOL_ERROR = 1
+    INTERNAL_ERROR = 2
+    FLOW_CONTROL_ERROR = 3
+    SETTINGS_TIMEOUT = 4
+    STREAM_CLOSED = 5
+    FRAME_SIZE_ERROR = 6
+    REFUSED_STREAM = 7
+    CANCEL = 8
+    COMPRESSION_ERROR = 9
+    CONNECT_ERROR = 10
+    ENHANCE_YOUR_CALM = 11
+    INADEQUATE_SECURITY = 12
+    HTTP_1_1_REQUIRED = 13
+
+
+class Settings(enum.Enum):
+    HEADER_TABLE_SIZE = 1
+    ENABLE_PUSH = 2
+    MAX_CONCURRENT_STREAMS = 3
+    INITIAL_WINDOW_SIZE = 4
+    MAX_FRAME_SIZE = 5
+    MAX_HEADER_LIST_SIZE = 6
+
+
+def connect(hostname):
+    '''Returns socket with secure h2 connection'''
+    ssl_ctx = ssl.create_default_context()
+    ssl_ctx.set_alpn_protocols(['h2'])
+    sock = socket.create_connection((hostname, 443))
+    sock = ssl_ctx.wrap_socket(sock, server_hostname=hostname)
+    assert sock.selected_alpn_protocol() == 'h2'
+    return sock
+
+
+def write(sock, data):
+    '''Send data (h2 frame or raw bytes)'''
+    if isinstance(data, hyperframe.frame.Frame):
+        print("> ", data)
+        data = data.serialize()
+    else:
+        print("> ", data)
+
+    sock.sendall(data)
+
+
+def read_bytes(sock, num_bytes):
+    '''Read exact number of bytes from socket'''
+    data = b''
+    while len(data) < num_bytes:
+        rcv = sock.recv(num_bytes - len(data))
+        if not rcv:
+            exit('connection over')
+        data += rcv
+    return data
+
+
+def read_frame(sock):
+    '''Read exactly 1 h2 frame from socket '''
+    data = read_bytes(sock, 9)
+    frame, payload_len = hyperframe.frame.Frame.parse_frame_header(data)
+    if payload_len:
+        data = read_bytes(sock, payload_len)
+        frame.parse_body(memoryview(data))
+
+    return frame
+
+
+if __name__ == '__main__':
+    # connect
+    hostname = 'www.google.com'
+    hpack_enc = hpack.Encoder()
+    hpack_dec = hpack.Decoder()
+    sock = connect(hostname)
+
+    # send connection preface
+    write(sock, MAGIC)
+    write(sock, hyperframe.frame.SettingsFrame())
+
+    # send request
+    headers = hyperframe.frame.HeadersFrame(3)
+    headers.data = hpack_enc.encode([
+        (b':method', b'GET'),
+        (b':scheme', b'https'),
+        (b':authority', b'www.google.com'),
+        (b':path', b'/'),
+    ])
+    headers.flags.add('END_HEADERS')
+    headers.flags.add('END_STREAM')
+    write(sock, headers)
+
+    # read frames
+    while True:
+        frame = read_frame(sock)
+        print("< ", frame, 'body_len:', frame.body_len)
+        if isinstance(frame, hyperframe.frame.HeadersFrame):
+            print('   ', hpack_dec.decode(frame.data))
+
+        if isinstance(frame, hyperframe.frame.DataFrame):
+            if len(frame.data) < 70:
+                print('    {}'.format(frame.data))
+            else:
+                print('    {}...'.format(frame.data[:70]))
+
+        if isinstance(frame, hyperframe.frame.GoAwayFrame):
+            print('    error_code:{} last_stream_id:{}'.format(
+                ErrorCode(frame.error_code).name, frame.last_stream_id))
+
+        if isinstance(frame, hyperframe.frame.RstStreamFrame):
+            print('    error_code:{}'.format(ErrorCode(frame.error_code).name))
+
+        if isinstance(frame, hyperframe.frame.SettingsFrame) and not 'ACK' in frame.flags:
+            print('   ', {Settings(k).name: v for k,
+                          v in frame.settings.items()})