add HTTP/2-capable client

netlib/h2/h2.py

@@ -1,3 +1,5 @@
+from .. import utils, odict, tcp
+from frame import *
 
 # "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n"
 CLIENT_CONNECTION_PREFACE = '505249202a20485454502f322e300d0a0d0a534d0d0a0d0a'
@@ -18,3 +20,66 @@ ERROR_CODES = utils.BiDi(
     INADEQUATE_SECURITY=0xc,
     HTTP_1_1_REQUIRED=0xd
 )
+
+
+class H2Client(tcp.TCPClient):
+    ALPN_PROTO_H2 = b'h2'
+
+    DEFAULT_SETTINGS = {
+        SettingsFrame.SETTINGS.SETTINGS_HEADER_TABLE_SIZE: 4096,
+        SettingsFrame.SETTINGS.SETTINGS_ENABLE_PUSH: 1,
+        SettingsFrame.SETTINGS.SETTINGS_MAX_CONCURRENT_STREAMS: None,
+        SettingsFrame.SETTINGS.SETTINGS_INITIAL_WINDOW_SIZE: 2 ^ 16 - 1,
+        SettingsFrame.SETTINGS.SETTINGS_MAX_FRAME_SIZE: 2 ^ 14,
+        SettingsFrame.SETTINGS.SETTINGS_MAX_HEADER_LIST_SIZE: None,
+    }
+
+    def __init__(self, address, source_address=None):
+        super(H2Client, self).__init__(address, source_address)
+        self.settings = self.DEFAULT_SETTINGS.copy()
+
+    def connect(self, send_preface=True):
+        super(H2Client, self).connect()
+        self.convert_to_ssl(alpn_protos=[self.ALPN_PROTO_H2])
+
+        alp = self.get_alpn_proto_negotiated()
+        if alp != b'h2':
+            raise NotImplementedError("H2Client can not handle unknown protocol: %s" % alp)
+        print "-> Successfully negotiated 'h2' application layer protocol."
+
+        if send_preface:
+            self.wfile.write(bytes(CLIENT_CONNECTION_PREFACE.decode('hex')))
+            self.send_frame(SettingsFrame())
+
+            frame = Frame.from_file(self.rfile)
+            print frame.human_readable()
+            assert isinstance(frame, SettingsFrame)
+            self.apply_settings(frame.settings)
+
+            print "-> Connection Preface completed."
+
+        print "-> H2Client is ready..."
+
+    def send_frame(self, frame):
+        self.wfile.write(frame.to_bytes())
+        self.wfile.flush()
+
+    def read_frame(self):
+        frame = Frame.from_file(self.rfile)
+        if isinstance(frame, SettingsFrame):
+            self.apply_settings(frame.settings)
+
+        return frame
+
+    def apply_settings(self, settings):
+        for setting, value in settings.items():
+            old_value = self.settings[setting]
+            if not old_value:
+                old_value = '-'
+
+            self.settings[setting] = value
+            print "-> Setting changed: %s to %d (was %s)" %
+                (SettingsFrame.SETTINGS.get_name(setting), value, str(old_value))
+
+        self.send_frame(SettingsFrame(flags=Frame.FLAG_ACK))
+        print "-> New settings acknowledged."

test/h2/example.py

@@ -0,0 +1,20 @@
+from netlib import tcp
+from netlib.h2.frame import *
+from netlib.h2.h2 import *
+from hpack.hpack import Encoder, Decoder
+
+c = H2Client(("127.0.0.1", 443))
+c.connect()
+
+c.send_frame(HeadersFrame(
+    flags=(Frame.FLAG_END_HEADERS | Frame.FLAG_END_STREAM),
+    stream_id=0x1,
+    headers=[
+        (b':method', 'GET'),
+        (b':path', b'/index.html'),
+        (b':scheme', b'https'),
+        (b':authority', b'localhost'),
+    ]))
+
+while True:
+    print c.read_frame().human_readable()