PHP: How to return information to a waiting script and continue processing

Question

Suppose there are two scripts Requester.php and Provider.php, and Requester requires processing from Provider and makes an http request to it (Provider.php?data=\"data\"). In th

Answer 1

You could start another php process in Provider.php using pcntl_fork()

Provider.php 
{
    // Fork process
    $pid = pcntl_fork();

    // You are now running both a daemon process and the parent process
    // through the rest of the code below

    if ($pid > 0) {
        // PARENT Process
        $answer = getAnswer($_GET['data']);
        echo $answer;    
        //SIGNAL TO REQUESTER THAT WE ARE FINISHED
        return;
    }

    if ($pid == 0) {
        // DAEMON Process
        processDBUpdates();
        return;
    }

    // If you get here the daemon process failed to start
    handleDaemonErrorCondition();
    return;

}

Answer 2

I'm going out on a limb here, but perhaps you should try cURL or use a socket to update the requester?

Answer 3

I use this code for running a process in the background (works on Linux).

The process runs with its output redirected to a file.

That way, if I need to display status on the process, it's just a matter of writing a small amount of code to read and display the contents of the output file.

I like this approach because it means you can completely close the browser and easily come back later to check on the status.

Answer 4

You can flush the output buffer with the flush() command.
Read the comments in the PHP manual for more info

Answer 5

Split the Provider in two: ProviderCore and ProviderInterface. In ProviderInterface just do the "quick and easy" part, also save a flag in database that the recent request hasn't been processed yet. Run ProviderCore as a cron job that searches for that flag and completes processing. If there's nothing to do, ProviderCore will terminate and retry in (say) 2 minutes.

Answer 6

You basically want to signal the end of 1 process (return to the original Requester.php) and spawn a new process (finish Provider.php). There is probably a more elegant way to pull this off, but I've managed this a couple different ways. All of them basically result in exec-ing a command in order to shell off the second process.

adding the following > /dev/null 2>&1 & to the end of your command will allow it to run in the background without inhibiting the actual execution of your current script

Something like the following may work for you:

exec("wget -O - \"$url\" > /dev/null 2>&1 &"); 

-- though you could do it as a command line PHP process as well.

You could also save the information that needs to be processed and handle the remaining processing on a cron job that re-creates the same sort of functionality without the need to exec.