get real time Result shell using PHP [duplicate] - php

Question

This question already has answers here:
PHP reading shell_exec live output
(3 answers)
Closed 6 years ago.
I have to execute a batch file (I.e. .bat ) and get the result on an HTML page.
I used this PHP code to get a result:
<?php
echo "<br>";
$result = shell_exec('start file.bat');
iconv("CP850","UTF-8",$result);
echo "<pre>$result </pre>";
?>
Now the problem is that I get a result only when the batch file execution finishes, and I want to have the result in real time, like running via command line.

Answer 1

Found in the comments of the shell_exec documentation's page of PHP
If you're trying to run a command such as "gunzip -t" in shell_exec and getting an empty result, you might need to add 2>&1 to the end of the command, eg:
Won't always work:
echo shell_exec("gunzip -c -t $path_to_backup_file");
Should work:
echo shell_exec("gunzip -c -t $path_to_backup_file 2>&1");
In the above example, a line break at the beginning of the gunzip output seemed to prevent shell_exec printing anything else. Hope this saves someone else an hour or two.
I believe it is what you really have to do.
Reference: http://php.net/manual/en/function.shell-exec.php#106250

Answer 2

As already mentioned in the comments to your question you need to fork a process in such way that you can communicate with it. That is not possible with imple functions like exec() and the like.
Instead take a look at this simple example:
File test.sh:
#!/bin/bash
echo start counting ...
for counter in 1 2 3
do
echo * counter is at value $counter *
sleep 3
done
echo ... finished counting.
File test.php:
<?php
$descriptorspec = array(
0 => array('pipe', 'r'),
1 => array('pipe', 'w'),
);
echo "forking process ...\n";
$process = proc_open('./test.sh', $descriptorspec, $pipes);
if (is_resource($process)) {
echo "... successfully forked process ...\n";
while (!feof($pipes[1])) {
echo fread($pipes[1], 1024);
flush();
}
echo "... process has finished ...\n";
fclose($pipes[0]);
fclose($pipes[1]);
echo "... pipes closed ...\n";
proc_close($process);
echo "... process closed.\n";
} else {
echo "... failed to fork process!\n";
}
The obvious output of a test run of that php script is:
forking process ...
... successfully forked process ...
start counting ...
* counter is at value 1 *
* counter is at value 2 *
* counter is at value 3 *
... finished counting.
... process has finished ...
... pipes closed ...
... process closed.
But the interesting part here is that this output is not sent in one go once that forked process has finished, but in what you referred to as "a live manner". So the first four lines appear immediately, the next two with a 3 second delay each, then the rest of the output.
Please note that the above example is meant as a demonstration for a Linux CLI environment. So it does not care about html markup but outputs plain text and relies on bash as a shell environment for the forked process. You will have to adapt that simple demonstration to your needs, obviously.