plain_sockets_client.py

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#!/usr/bin/env python3

"""

plain_sockets_client.py

~~~~~~~~~~~~~~~~~~~~~~~

Just enough code to send a GET request via h2 to an HTTP/2 server and receive a response body.

This is *not* a complete production-ready HTTP/2 client!

"""

import socket

import ssl

import certifi

import h2.connection

import h2.events

SERVER_NAME = 'http2.golang.org'

SERVER_PORT = 443

# 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)

c = h2.connection.H2Connection()

c.initiate_connection()

s.sendall(c.data_to_send())

headers = [

    (':method', 'GET'),

    (':path', '/reqinfo'),

    (':authority', SERVER_NAME),

    (':scheme', 'https'),

c.send_headers(1, headers, end_stream=True)

s.sendall(c.data_to_send())

body = b''

response_stream_ended = False

while not response_stream_ended:

    # read raw data from the socket

    data = s.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

            c.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

    s.sendall(c.data_to_send())

print("Response fully received:")

print(body.decode())

# tell the server we are closing the h2 connection

c.close_connection()

s.sendall(c.data_to_send())

# close the socket

s.close()