Can I use Requests to handle HTTP/2 push promises?

The requests library in Python is a popular tool for making HTTP/1.1 requests. However, it does not support HTTP/2, nor does it handle HTTP/2 features such as Server Push (also known as Push Promises). This is because requests is built on top of urllib3, which does not support HTTP/2.

If you need to handle HTTP/2 push promises in Python, you would have to use a different library that supports HTTP/2. One such library is httpx, which is a fully featured HTTP client for Python 3, which provides async capabilities and HTTP/2 support.

Here's an example of how you might use httpx to make an HTTP/2 request:

import httpx

# Create an HTTP/2 client
client = httpx.Client(http2=True)

# Make a request to an HTTP/2-enabled server
response = client.get('https://http2.akamai.com/demo')

# Display the result
print(response.text)

# Close the client
client.close()

However, handling push promises specifically is not as straightforward. httpx does not provide a direct API to handle server pushes. You'd have to use a lower-level library like hyper or h2, which give you more control over the HTTP/2 protocol but are more complex to use.

Here's a very basic example using the h2 library:

import h2.connection
import h2.events

# Create an H2 connection instance
conn = h2.connection.H2Connection()

# Start the HTTP/2 connection, replace with your server's host and port
conn.initiate_connection()
sock.sendall(conn.data_to_send())

# Send a request, replace with your actual request details
headers = [
    (':method', 'GET'),
    (':authority', 'http2.akamai.com'),
    (':scheme', 'https'),
    (':path', '/'),
    ('user-agent', 'python-h2/1.0.0'),
]
conn.send_headers(1, headers, end_stream=True)
sock.sendall(conn.data_to_send())

# Read from the socket and handle events
while True:
    data = sock.recv(65535)
    if not data:
        break

    events = conn.receive_data(data)
    for event in events:
        if isinstance(event, h2.events.PushedStreamReceived):
            pushed_headers = event.headers
            print('Received server push promise:', pushed_headers)
        elif isinstance(event, h2.events.DataReceived):
            conn.acknowledge_received_data(event.flow_controlled_length, event.stream_id)
        elif isinstance(event, h2.events.StreamEnded):
            print('Stream ended:', event.stream_id)

    sock.sendall(conn.data_to_send())

In this example, sock would be a socket-like object that you've connected to an HTTP/2 capable server. The h2 library lets you interact with the HTTP/2 protocol directly, so you would need to manage the socket reads and writes yourself.

Remember that HTTP/2 push is a server-initiated feature. A server may choose to push resources to the client, but the client does not have a way to specifically request a push promise. The client can only accept or reject pushes from the server.

If you're not bound to Python and are open to using Node.js, there are libraries like http2 (built into Node.js as of version 8.4.0) that you can use to handle HTTP/2 communications, including server push.