Regarding one Ajax call blocked by another Ajax call

[Saransh Gupta]

Hello,

I have a web-app that is running on host A, it runs a few commands on another host B and i want to display the output of the commands running on B on a webpage present on A i.e. i want to create a kind of live streaming of B's console on a webpage present on A.

For this what i did is I redirected the output of B's console to a socket on A and saved the output in a file on A.

I fire an ajax call that initiates the process(using web2py controller) to start at B. This ajax call also handles the redirection of B's  console to A's socket.

From the webpage I fire another ajax that reads the file in which the data  of the socket is being stored.

Now the problem I am facing is that when I fire the secodn ajax call it does not returns to the webpage untill the first ajax call is returned.

I want to know that is this the correct way of doing this. Also i want to know that, the problem I am facing is due to ajax or web2py framework?

-Saransh

[Anthony]

By default, the session file is locked upon each request, so a new request from the same client is blocked until the previous request is completed and the session file is unlocked (see here). To avoid this problem, you can do one of the following:

• In your app code, when a request for the Ajax function comes in, immediately call session.forget(response).  This will unlock the session file (and therefore prevent the session from being saved for that request). You can include this line at the beginning of the Ajax function itself, or you can include it earlier in a model file:

if request.function in [list, of, ajax, functions]:
    session.forget(response)

• Store sessions in the database or in cookies, in which case there will be no session files to be locked.
• If you are not using the parameter-based rewrite system, you can use the pattern-based rewrite system to disable automatic session connecting for particular routes. In routes_in, instead of specifying a standard 2-tuple, you can specify a 3-tuple. The first two elements of the tuple are as usual (incoming pattern and re-written pattern), and the third element should be dict(web2py_disable_session=True). That will prevent the framework from automatically connecting the session for that route (you can still manually connect the session in your app code). In theory, this is a little more efficient than the first option because it prevents the session file from being locked at all (with the first option, the framework still initially locks the session file, and then your app code unlocks it a bit later).

Anthony

[saransh]

Its working after using session.forget(response)

Thank you for your reply.