How can one use multi threading in PHP application

Question

Is there a realistic way of implementing a multi-threaded model in PHP whether truly, or just simulating it. Some time back it was suggested that you could force the operating system to load another instance of the PHP executable and handle other simultaneous processes.

The problem with this is that when the PHP code finished executing the PHP instance remains in memory because there is no way to kill it from within PHP. So if you are simulating several threads you can imagine whats going to happen. So I am still looking for a way multi-threading can be done or simulated effectively from within PHP. Any ideas?

Answer 1

I know this is way old, but you could look at http://phpthreadlib.sourceforge.net/

It supports bi-directional inter-thread communication and also has builtin protections for killing off child threads (preventing orphans).

Answer 2

May be I missed something but exec did not worked as asynchronous for me in windows environment i used following in windows and it worked like charm ;)

$script_exec = "c:/php/php.exe c:/path/my_ascyn_script.php";

pclose(popen("start /B ". $script_exec, "r"));

Answer 3

I know this is an old question but for people searching, there is a PECL extension written in C that gives PHP multi-threading capability now, it's located here https://github.com/krakjoe/pthreads

Answer 4

Depending on what you're trying to do you could also use curl_multi to achieve it.

Answer 5

pcntl_fork won't work in a web server environment if it has safe mode turned on. In this case, it will only work in the CLI version of PHP.

Answer 6

As of the writing of my current comment, I don't know about the PHP threads. I came to look for the answer here myself, but one workaround is that the PHP program that receives the request from the web server delegates the whole answer formulation to a console application that stores its output, the answer to the request, to a binary file and the PHP program that launched the console application returns that binary file byte-by-byte as the answer to the received request. The console application can be written in any programming language that runs on the server, including those that have proper threading support, including C++ programs that use OpenMP.

One unreliable, dirty, trick is to use PHP for executing a console application, "uname",

uname -a

and print the output of that console command to the HTML output to find out the exact version of the server software. Then install the exact same version of the software to a VirtualBox instance, compile/assemble whatever fully self-contained, preferably static, binaries that one wants and then upload those to the server. From that point onwards the PHP application can use those binaries in the role of the console application that has proper multi-threading. It's a dirty, unreliable, workaround to a situation, when the server administrator has not installed all needed programming language implementations to the server. The thing to watch out for is that at every request that the PHP application receives the console application(s) terminates/exit/get_killed.

As to what the hosting service administrators think of such server usage patterns, I guess it boils down to culture. In Northern Europe the service provider HAS TO DELIVER WHAT WAS ADVERTISED and if execution of console commands was allowed and uploading of non-malware files was allowed and the service provider has a right to kill any server process after a few minutes or even after 30 seconds, then the hosting service administrators lack any arguments for forming a proper complaint. In United States and Western Europe the situation/culture is very different and I believe that there's a great chance that in U.S. and/or Western Europe the hosting service provider will refuse to serve hosting service clients that use the above described trick. That's just my guess, given my personal experience with U.S. hosting services and given what I have heard from others about Western European hosting services. As of the writing of my current comment(2018_09_01) I do not know anything about the cultural norms of the Southern-European hosting service providers, Southern-European network administrators.