Execute php script

Question

I am building a php application. In a script, there is a call to execute a jar file:

?php
exec('java -jar simulations/simulation.jar');
?>

The problem is that this command line executes the jar file:

user@ubuntu: php execSimulation.php

but not the call from the web page. The call is made by AJAX, am I missing something??

<!-- Script to execute the simulation -->
<script type="text/javascript" src="prototype.js"></script>
        <script>

            function sendRequest() {
                new Ajax.Request("ejecutarSimulacion.php", 
                    { 
                    method: 'post', 
                    postBody: 'name='+ $F('name'),
                    onComplete: showResponse 
                    });
                }

            function showResponse(req){
            alert(req.responseText);
            }
        </script>

<form id="test" onsubmit="return false;">
                                <input type="hidden" value="<?php echo $simulacion; ?>" name="name" id="name" >
                                <input type="submit" value="<?php echo $nombre; ?>" onClick="sendRequest()">
                            </form>

When I try to print only the param I send, for instance, the alert shows it, so I am sure that the call is reaching the the server, but I don't know why the jar file is not executed. Any ideas, please?

Thanks in advance.

EDIT

Error trace:

No protocol specified
Exception in thread "main" java.lang.InternalError: Can't connect to X11 window server using ':0.0' as the value of the DISPLAY variable.
    at sun.awt.X11GraphicsEnvironment.initDisplay(Native Method)
    at sun.awt.X11GraphicsEnvironment.access$200(X11GraphicsEnvironment.java:62)
    at sun.awt.X11GraphicsEnvironment$1.run(X11GraphicsEnvironment.java:178)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.awt.X11GraphicsEnvironment.<clinit>(X11GraphicsEnvironment.java:142)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:186)
    at java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsEnvironment.java:82)
    at java.awt.Window.init(Window.java:385)
    at java.awt.Window.<init>(Window.java:438)
    at java.awt.Frame.<init>(Frame.java:419)
    at java.awt.Frame.<init>(Frame.java:384)
    at javax.swing.JFrame.<init>(JFrame.java:174)
    at org.opensourcephysics.tools.TranslatorTool.<init>(Unknown Source)
    at org.opensourcephysics.tools.TranslatorTool.<clinit>(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:186)
    at org.opensourcephysics.display.OSPRuntime.<clinit>(Unknown Source)
    at org.opensourcephysics.controls.OSPLog.fine(Unknown Source)
    at org.opensourcephysics.tools.ResourceLoader.addSearchPath(Unknown Source)
    at _users.tanqueCalentamiento.TanqueCalentamiento.<clinit>(TanqueCalentamiento.java:18)
Could not find the main class: _users.simulation.Simulation. Program will exit.

On ubuntu there a different php.ini config files for apache and cli. Do you have safe mode enabled in your /etc/php5/apache2/php.ini or is there a value in "safe_mode_exec_dir"...? — madflow, Aug 17 '11 at 18:45
Google claims this is the solution to the X problem: export DISPLAY=:0 (http://www.linuxquestions.org/questions/linux-general-1/cant-connect-to-x11-window-server-using-0-0-as-the-value-of-the-display-variable-178234/) — madflow, Aug 17 '11 at 19:07
The solution you mentioned on your second comment, doesn't make any change. In my php.ini I can find this line: safe_mode_exec_dir = — Blanca Hdez, Aug 17 '11 at 19:18

gen_Eric · Accepted Answer · 2011-08-17T19:41:15.170

2

It seems your jar requires an X server to be running.

Can't connect to X11 window server using ':0.0' as the value of the DISPLAY variable.

When you run it from command line, do you have X running? If you do, this would explain why it works there, and not from PHP.

You can try to "hijack" the running X session from PHP.

exec('DISPLAY=:0 java -jar simulations/simulation.jar');

You may have to first run xhost +localhost (or xhost +) from the command line, to allow the user PHP is running as to connect to X.

edited Aug 17 '11 at 19:41

answered Aug 17 '11 at 19:13

gen_Eric

223,194
41
299
337

1

22 goddamn seconds! I swear, one more bad beat like this one and I'm taking hostages. – Michael Lorton Aug 17 '11 at 19:14
1

And you really should write `exec('DISPLAY=:0 java -jar simulations/simulation.jar');` – Michael Lorton Aug 17 '11 at 19:14
I am not very sure about what X server is. I'll look for information. Anyway, exec('DISPLAY=:0 java -jar simulations/simulation.jar'); is not executiong jar file :( – Blanca Hdez Aug 17 '11 at 19:25
X sever is GUI for linux systems. When you run it from command line, you're running it from a terminal window (you have a desktop), right? – gen_Eric Aug 17 '11 at 19:27
Thanks for the explanation and for the answers. Yes, I'm using a terminal window, where it executes the jar file. But not from the php script – Blanca Hdez Aug 17 '11 at 19:29
Now the error says: Can't connect to X11 window server using ':0' as the value of the DISPLAY variable. Which is the right value? – Blanca Hdez Aug 17 '11 at 19:30
mujeresponja@ubuntu:~$ xhost + access control disabled, clients can connect from any host – Blanca Hdez Aug 17 '11 at 19:34
@Rocket let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/2587/discussion-between-blanca-hdez-and-rocket) – Blanca Hdez Aug 17 '11 at 19:36
Would I make things in a different way on Windows?? I am running the same process and it stays blocked: I tryed to remove 'DISPLAY=:0', try to get an error trace, but the process is just blocked. Thanks again – Blanca Hdez Sep 03 '11 at 12:09
I don't know how do to this on Windows, sorry. – gen_Eric Sep 03 '11 at 20:29
Just to let you know: in Windows is necessary to start/stop xampp server as administrator – Blanca Hdez Sep 08 '11 at 05:04

score 2 · Answer 2 · answered Aug 17 '11 at 19:13

In the immortal words of Jamie Savage, "There's yer problem."

The Java program you're running is trying to get to your X Windows "server" (i.e., the screen) on initialization, which works when you're running from the command line but not from the headless web-server. Talk to the people who wrote org.opensourcephysics.tools.TranslatorTool about how to disable this (grossly dysfunctional) behavior.

score 0 · Answer 3 · answered Aug 17 '11 at 18:24

0

Use the full path in exec() : base paths are different between the CLI SAPI and the apache one.

 <?php 
 exec('full/path/to/jar');

answered Aug 17 '11 at 18:24

Benjamin Dubois

971
7
11

thanks for answering. I tried, but the same result: exec('java -jar /opt/lampp/htdocs/blanca/simulations/simulation.jar'); – Blanca Hdez Aug 17 '11 at 18:35
is the php file in the same folder than the webpage which loads the script ? – Benjamin Dubois Aug 17 '11 at 18:37
Yes. both of them are in /opt/lampp/htdocs/blanca/ then, the jar files in /opt/lampp/htdocs/blanca/simulations – Blanca Hdez Aug 17 '11 at 18:38
The path to the java executable should also be made absolute. `/usr/bin/jre/java` or whatever it happens to be. – Marc B Aug 17 '11 at 18:41
The jar is not ecexuted with this command: exec('/usr/lib/jvm/java-6-openjdk/jre/bin/java -jar /opt/lampp/htdocs/blanca/simulations/simulation.jar'); – Blanca Hdez Aug 17 '11 at 18:56
Please, check the edit in my question, maybe the probelm is clearer for you. Thanks – Blanca Hdez Aug 17 '11 at 19:02

Execute php script

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