feat: add http_cookie to WebsocketSession and UserSession

[5enxia]

This is a partial solution to this issue. #1213

Adding access to http_cookie to WebSocketSession and UserSession facilitates the use of chainlit in enterprise applications that deploy multiple services under the same domain.

Pull Request Summary

This pull request introduces support for handling HTTP cookies in the backend/chainlit module. The changes primarily involve adding a new http_cookie parameter to various methods and ensuring that this parameter is properly propagated throughout the session handling and testing code.

Session handling updates:

• backend/chainlit/session.py: Added http_cookie parameter to the __init__ method of several classes to handle HTTP cookies. [1] [2] [3] [4] [5] [6]
• backend/chainlit/socket.py: Added http_cookie extraction from the environment and passed it to the session initialization. [1] [2]
• backend/chainlit/user_session.py: Updated get method to include http_cookie in the user session dictionary.

Testing updates:

• backend/tests/conftest.py: Updated create_mock_session to include the http_cookie parameter.
• backend/tests/test_user_session.py: Added assertion to check http_cookie in the test_user_session_set_get test case.

[5enxia]

How to check (with Chrome)

Frontend

1. Open Browser Developer Tools.
2. Select the Application tab.
3. Select the relevant domain from Storage → Cookies.
4. Add the following cookie:

• Name: foo
• Value: bar

Or run the following command in the Console tab:

document.cookie = "foo=bar;"

Backend

Please write below code in chainlit's entry file. (ex: hello.py)
And check log.

# This is a simple example of a chainlit app.
from chainlit import AskUserMessage, Message, on_chat_start
import chainlit as cl

# logger
import logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

@on_chat_start
async def main():
    http_cookie = cl.user_session.get("http_cookie")
    logger.info(f"http_cookie: {http_cookie}")

    res = await AskUserMessage(content="What is your name?", timeout=30).send()
    if res:
        await Message(
            content=f"Your name is: {res['output']}.\nChainlit installation is working!\nYou can now start building your own chainlit apps!",
        ).send()

[willydouhard]

Thank you for your contribution!

[5enxia]

Thank you for review and merge!