Asynchronous HTTP requests

samir_d · February 21, 2018, 11:32am

Hi,

I have an app that I need to make it send http requests and receive response , but I want to make it send all requests that it has at once, is there any app in the NextCloud that behaves is similar way? or does the NextCloud server support such a capabilities?

Thanks

Cult · February 21, 2018, 12:20pm

You can setup a cron job, that will do the request at the next tick.

If you need something more ‘live’ you should have a look to the Circles apps: I found a (experimental) way to create an async process by sending a local request to the cloud:

Current webpage (process A) send a request to the local cloud
process B is opened by the request
process B is closing the socket, setting process A free
process A is now free and can stop
process B is still alive and do what ever you need to do.

github.com

nextcloud/circles/blob/master/lib/Service/MiscService.php#L277-L290


	public function asyncAndLeaveClientOutOfThis($result = '') {
		if (ob_get_contents() !== false) {
			ob_end_clean();
		}


		header('Connection: close');
		ignore_user_abort();
		ob_start();
		echo(json_encode($result));
		$size = ob_get_length();
		header('Content-Length: ' . $size);
		ob_end_flush();
		flush();
	}

samir_d · February 21, 2018, 2:23pm

Thanks,

I don’t think that “cron job” is suitable since the requests depend on events so I cant predict when to send and when not to, but the code that you have shared sound reasonable enough.

but how can I use it correctly? assume I have in the php script a function called PostRequest(), is this syntax is correct?

<?php
$this->miscService->asyncAndLeaveClientOutOfThis($this->PostRequest());

I saw that it was used in a similar way at the TestController.php code, the line was like this:

<?php
$this->miscService->asyncAndLeaveClientOutOfThis($this->testAsyncStatus());

I presume I should do the same correct?

Cult · February 21, 2018, 3:09pm

There string you’re sending as a parameter to asyncAndLeaveClientOutOfThis() is totally useless.

The asyncTestRun method is called by a PUT request to /admin/testAsync

The PUT request is made by the process A
it open a new process B that call the asyncAndLeaveClientOutOfThis
from now on, everything in the asyncTestRun() after this line is run in the process B, and process A died.

You can see that there is a while() that run for 120 seconds that keep process B alive while A is gone.