Scheduling external commands in PHP

Anon

Hey all,

I am trying with little success to use PHP to schedule a command to be executed on the system at a certain time. Basically, this is what I want:

The user fills in information for an email job to be processed via a web interface. Because of the time it takes to generate the emails with information from database I wanted this to happen in the background instead of tying the users web browser up. I work a php shell script that generates the emails and it works great. But when I try to use 'at' to schedule it from within php, it processes the script and sends the email and doesnt schedule the job. Code segment:

echo("System Time: $now<br>");
echo("Job Scheduled for: $at<br>");

system("./phpscript | at now + 1 minutes");

Any ideas how I can set this up to be submissible via the web, then just run the job in the background at whatever time?

I have tried exec, passthru and system and each one of them does the same thing, it executes the script before it attempts to schedule the job, thus sending out the emails before I want them to go.

Thanks!

Joe

Anon

I had a lot of fun getting this sort of thing to work (to tidy up old files, print reports etc).

What I resorted to was a 2 or 3 stage process a hybrid between PHP and Unix shell scripts. It aint pretty, but it does work:

Generate your task

Use PHP to generate a file with some user input in it (put it outside the web tree and don't forget to validate the contents).
Carry out the task

Set up a cron job (shell script scheduled via cron) to run through the files every N seconds, and process them. On successful completion of the required actions, the shell script can delete the file. Do NOT run the cron job from a privileged account eg: root.

Check periodically that all's well

Just get a regularly used script on your site to check that the Cron job is still there and to restart it if it's not.

No doubt there are more elegant ways but this works for me.

Hope this helps

Paul

Anon

This is what I ended up doing
, kinda unelegant but it works as I need it to:

$fp = fopen ("atfile_$id", "w");

fputs($fp, "#!/bin/sh\n\n");
fputs($fp, "./background $id\n");
fclose($fp);

system("chmod +x atfile$id");
system("at now + 1 minutes -f atfile$id");

Thanks for your input!

Joe