http2.py

import socket
import ssl
import certifi

# python -m pip install h2
import h2.connection
import h2.events

SERVER_NAME = 'namemc.com'
SERVER_PORT = 443


def get_ssl_connection(name: str, port: int = 443) -> ssl.SSLSocket:
    # generic socket and ssl configuration
    socket.setdefaulttimeout(15)
    ctx = ssl.create_default_context(cafile=certifi.where())
    ctx.set_alpn_protocols(['h2'])

    # open a socket to the server and initiate TLS/SSL
    s = socket.create_connection((SERVER_NAME, SERVER_PORT))
    s = ctx.wrap_socket(s, server_hostname=SERVER_NAME)
    return s


def send_http2_preamble(sock: ssl.SSLSocket):
    sock.send(b"PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n")


def update_settings(conn: h2.connection.H2Connection,
                    sock: ssl.SSLSocket) -> None:
    conn.update_settings({
        h2.settings.SettingCodes.MAX_CONCURRENT_STREAMS: 65536,
        h2.settings.SettingCodes.INITIAL_WINDOW_SIZE: 65535
    })

    sock.sendall(conn.data_to_send())


def send_prio_frames(conn: h2.connection.H2Connection,
                     sock: ssl.SSLSocket) -> None:
    conn.prioritize(3, 201, 0, False)
    conn.prioritize(5, 101, 0, False)
    conn.prioritize(7, 1, 0, False)
    conn.prioritize(9, 7, 0, False)
    conn.prioritize(11, 1, 3, False)

    sock.sendall(conn.data_to_send())


def send_headers(conn: h2.connection.H2Connection,
                 sock: ssl.SSLSocket) -> None:
    headers = [
        (':method', 'GET'),
        (':path', '/'),
        (':scheme', 'https'),
        (':authority', SERVER_NAME),
        ('accept', '*/*'),
        ('user-agent', 'ThisIsntImportant'),
    ]
    conn.send_headers(1, headers, end_stream=True)
    sock.sendall(conn.data_to_send())


def receive_data(conn: h2.connection.H2Connection, sock: ssl.SSLSocket) -> str:
    body = b''
    response_stream_ended = False
    while not response_stream_ended:
        # read raw data from the socket
        data = sock.recv(65536 * 1024)
        if not data:
            break

        # feed raw data into h2, and process resulting events
        events = c.receive_data(data)
        for event in events:
            print(event)
            if isinstance(event, h2.events.DataReceived):
                # update flow control so the server doesn't starve us
                conn.acknowledge_received_data(event.flow_controlled_length,
                                               event.stream_id)
                # more response body data received
                body += event.data
            if isinstance(event, h2.events.StreamEnded):
                # response body completed, let's exit the loop
                response_stream_ended = True
                break
        # send any pending data to the server
        sock.sendall(conn.data_to_send())
    return body.decode()


if __name__ == "__main__":
    s = get_ssl_connection(SERVER_NAME, SERVER_PORT)
    c = h2.connection.H2Connection()

    # send data to look like a valid client
    send_http2_preamble(s)
    update_settings(c, s)
    send_prio_frames(c, s)
    send_headers(c, s)

    # receive data from the server
    body = receive_data(c, s)
    print(body)

    # close the h2 connection
    c.close_connection()
    s.sendall(c.data_to_send())

    # close the socket
    s.close()