How to run exec()/ linux commands using gearman extension from cakephp application? - php

Question

I installed gearman extension and gearman command line tool also. I tried to reverse a string using gearman from simple php file.
Example:
$gmclient= new GearmanClient();
$gmclient->addServer();
$result = $gmclient->doNormal("reverse", "Test the reverse string");
echo "Success: $result\n";
output:
Success: gnirts esrever eht tseT
In the same way i tried to run exec('ls -l') , I am able to execute using simple php files from cakephp application from webroot directory. filepath: cakephp/app/webroot/worker.php, cakephp/app/webroot/client.php.
worker.php
<?php
$worker= new GearmanWorker();
$worker->addServer();
$worker->addFunction("exec", "executeScript");
while ($worker->work());
function executeScript($job)
{
$param = $job->workload();
$t = exec($param);
return $t;
}
?>
client.php
<?php
$client= new GearmanClient();
$client->addServer();
$cmd = 'ls -l';
print $client->do("exec", $cmd);
?>
How to implement the same type of execution using View, Controller from cakephp?
Workflow: Post data from View to Controller using ajax method and execute "exec() from gearman" , send output back to View as response of ajax POST methhod.

Answer 1

Why are you using exec?! That brings a huge security risk. Use DirectoryIterator instead.
Your client code should be part of the controller.
<?php
class UploadController extends AppController
{
public function directoryList()
{
$directory = '';
// Get data
if (!empty($this->data['directory']) && is_string($this->data['directory']))
{
$directory = $this->data['directory'];
}
$client= new GearmanClient();
$client->addServer("localhost",4730); // Important!!!
$result = $client->do("fileList", serialize($data));
return $result;
}
}
Then from view use requestAction.
$uploads = $this->requestAction(
array('controller' => 'upload', 'action' => 'directoryList'),
array('return')
);
Worker could look like this:
<?php
$worker= new GearmanWorker();
$worker->addServer("localhost",4730); // Important!!!
$worker->addFunction("fileList", "getFileList");
while ($worker->work());
// From Art of Web
// http://www.the-art-of-web.com/php/directory-list-spl/
function getFileList($dir)
{
// array to hold return value
$retval = array();
$dir = $job->workload();
// add trailing slash if missing
if(substr($dir, -1) != "/") $dir .= "/";
// open directory for reading
$d = new DirectoryIterator($dir) or die("getFileList: Failed opening directory $dir for reading");
foreach($d as $fileinfo) {
// skip hidden files
if($fileinfo->isDot()) continue;
$retval[] = array(
'name' => "{$dir}{$fileinfo}",
'type' => ($fileinfo->getType() == "dir") ?
"dir" : mime_content_type($fileinfo->getRealPath()),
'size' => $fileinfo->getSize(),
'lastmod' => $fileinfo->getMTime()
);
}
return $retval;
}
This is pseudo code. Do not use it in production!!! See Gearman documentation for more advance worker setup.
To actually take advantage of load distribution Gearman server should not be on localhost of course.

Answer 2

Your worker.php needs to be already running on a server for this to work. For testing, open up a new terminal window to the server where you want worker.php to run. Start the worker: php worker.php on the command line. (On a production server, you might want to look at supervisor to run your worker without a terminal.)
The code in client.php would go in your controller, but save the result to a variable instead of a print statement.
The fact that this would be from an AJAX call is irrelevant, it will work the same as a normal web page. When the controller executes, the gearman client code will get a response from the worker, and you can output the result to the view.