i start a linux console app from my php5 script, it starts ok but then termintates. I've tried using system(), shell_exec and tried starting as background process but to no avail it starts and then quits.
What i am trying to achieve is from a remote browser start a console app using a php5 script and then it should remain running (just as it would if i started it from a bash shell) , i then want to send commands (from a bash shell it would be keyboard strokes) to the console app from another set of php5 scripts. Hope its clear what i am trying to do.
If anyone could give some info on the best way about doing this, as i think i may have something fundamentally wrong.
I have a Debian Lenny box running apache.The console app is just a simple program that prints to stdout and reads from stdin.
How do you expect to send input to this app? Where is it listening for input?
It simply may only support interactive use, and exit as a result of that. Or, even simpler, it may terminate because it sees that is has no input (nothing piped in or nothing from some file) and since it's not connected to an interactive shell, it has nothing to do. There's no point in waiting for input from a user that doesn't have a way to interact w/ the application.
On every request, PHP starts up, compiles your script and executes it. After execution, the script exists. When the script exits, all of the resources it was using, including file handles, database handles, and pipes to other programs are terminated.
You're going to need to find another way to keep your program open and have PHP communicate with it. Otherwise, every request to your script is going to open a new copy of the program, and then both will exit when the PHP script is complete.
Unfortunately without knowing what the program is, it will be hard to offer suggestions on how to go about doing this.
Related
I am trying to run a bash script using php-ssh2. The script must run forever in the remote machine (the only way to stop it must be with pkill). The problem is that somehow the connection is closed and the bash script is killed.
Nohup, disown and screen... I tried everything and nothing really changed, it simply doesn't keep that script alive.
What can I do?
(I know that this is a security hole (HUGE) but this is just experimental, the main idea is using an HTML button, run a bash script in the server computer, using apache2)
Create a frequent cron job (every minute?) that first checks some kind of a flag (e.g. existence of certain file) before running a job.
In the PHP code, only raise the flag (create the file).
Does the script generate output? If not, check out the keep alive option of ssh.
I have tried reading and have understood PHP console to be a command-line interface (CLI) like one used in composer. I do not understand the difference between a web script and a console script. I do not see the use of having the two.
I want to crawl data from a certain link. Should I use a console script or web script and why?
Please explain in the simplest manner possible.
There is no difference between the two. In most instances, the same PHP script will run whether you execute it from the command line or via the web.
There is, however, a difference between the environment the script will execute within. A CLI script is initiated from and executed within your shell on your computer. It is very self-contained. A web script, on the other hand, is (typically) initiated via a HTTP request from a browser, passes over the web to a web server, is executed on that remote server and a result (typically a web page) is passed back to your browser. In the latter case, there are special environment variables related to the web request made available to the script.
It's a bit hard to know which is the best case for your web crawler script without knowing more detail. But I'd say a command line script is what you're after.
One difference between a web page and a CLI instance is the way the script is executed: webpages will be loaded via a web container, while CLI's will be usually executed by the shell used to launch the PHP. Due to this, a CLI might not have access to all $_SERVER variables as the webpage as practically there is no HTTP request involved.
CLI scripts are useful for doing background tasks that are not initiated by the web server, for example a cron job that periodically cleans your database, on one that executes queued jobs. Think of CLI as shell scripts, you can write a PHP script instead of a bash one.
The PHP interpreter is the same in both cases, and it's up to you to decide which one suits best your needs: webpages are more common, however if you need to have you server do some work without waiting for a web request, the you can go with CLI.
Well, basically a console script is the way for your task.
The difference resides in the fact a Webscript will block your browser, will not show your progress real-time, etc.
I was able to crawl and download about 6000 images from my beloved anime with a console script, showing the progress status, something harder with a Web script as the browser will cache the output. Also you can chain your script and also make some cron magic(assuming you are on nix box)
I have multiple php scripts running in my computer. I'd like to ask if there is any way to stop one php script and keep other scripts untouched?
Thank you very much!
Update: Sorry i assumed that most people are using Ubuntu/Linux.
Multiple php script is running in my Ubuntu OS laptop, each script is called by putting the link to my internet browser
Well, identify the script and then kill it, addressing it by its process id (kill <pid>).
Have a look through the process list, if you canned the interpreter with the script as an argument then it will show up there: ps aux|grep php. Or, if you use shebangs inside the script (so that you can call it without explicitly starting the php interpreter), then search for it by the script name...
You might have to switch your effective user id if that php script was not started by you.
is it possible to launch a php script in background on the webserver with js and let it run even if you change page or not visit the site at all and then get the current status if you call the php script in a second moment?
This php script will process data for hours and sleep for X seconds/minutes for each loops. If what I asked before is possible how can I even get "echos" from it if php will only generated an output only when the script ends?
Maybe this is not a job for PHP?
thank you
EDIT: on a windows machine with apache
It certainly is possible - I have several scripts that run 24/7 written in PHP. Check out Creating Daemons in PHP. It has good info on how to 'daemonize' a php script so that it will run like a service, and it also covers signal handling.
To get debugging output you would redirect to a log file. Do a search on "unix redirect output" as there is a lot of info available.
In Windows it's not much different from UNIX.
First of all, you need to create a PHP script with a run loop. For example, take a look at this: http://code.google.com/p/php-apns/ . This is a PHP "daemon": the main script, PushMonitor.php, runs forever, because it has an infinite loop. It polls a queue at regular intervals, then execute the actions and then wait. Really simple, actually!
The problem, in your case, is that you want to launch the "daemon" from a PHP script.
You may want to look at this: http://robert.accettura.com/blog/2006/09/14/asynchronous-processing-with-php/ (first example code) . You will execute something like launchBackgroundProcess('php myscript.php') .
Note that on the code there's the "start /b" command (and the "&" at the end of the command for UNIX). That is important, because otherwise your process would be killed when the PHP script of the web page is terminated (children process die after parent dies!).
Also, remember that the "php" executable (cli) must be in your path (so you can execute "php" from the command line).
Since the PHP script of the page launching the background process is going to terminate, you can't directly catch the "echoes" in a simple way. My suggestion is to write all output to a file (or a database etc), and then read the contents from that source when necessary.
So, instead of "echo", you will use file_put_contents() etc.
I am working on a site that require a php script running on a server without any request,
it is a bot script that keeps (not full time but at least once a day) checking client accounts and send alert messages to clients when something happens.
any ideas are appreciated.
Assuming you need to do this on linux, you may run any php script from the browser and from the CLI as well.
You may run a simple php script:
<? echo "Ana are mere"; ?>
like this:
php -f ./index.php
Be careful about file-permissions, and any bug that may creep inside your code, memory leaks or unallocated variables will become VERY visible now, as the process will run continuously.
If you dont want it running in the background all the time, take a look at crontab (http://unixgeeks.org/security/newbie/unix/cron-1.html) to be able to start jobs regularly.
-- edit--
take a look at php execute a background process and PHP: How to return information to a waiting script and continue processing
Basically you want to start a background process, and you may do this by either using exec() or fsockopen() or a file_get_contents() on your own script probably in this order, if don't have access to exec, or socket functions.
Also take a look at http://us2.php.net/manual/en/function.session-write-close.php so the "background script" won't "block" the request and http://us2.php.net/manual/en/function.ignore-user-abort.php
Use a cron job to do it http://www.cronjobs.org/
You can automatically call a script at any interval you like indefinitely. Your hosting provider should support them if they are good.
You should also consider putting a unique key on the end of the page
ie. www.yoursite.com/cronjob.php?key=randomstring
and then only run the script if the key is correct, to prevent bots and other users from running the script when you don't want it run.
If you can't create a cron job, then create a page that does what you want and create a scheduled task on another machine (maybe your PC?) that just goes out and hits that page at a certain time every day.
It's really a hack, but if you absolutely can't set up a cron job, it would be an option.
As Evernoob and Quamis said, you want to have a cron job (UNIX/Linux/Mac OS) or a scheduled task (MS Windows). Furthermore, you can either have the PHP script run using the PHP command line interface (CLI), in which case you can invoke the PHP executable and then your script name. As an alternate, you can use a tool like wget (availble on all platforms) to invoke the PHP script as if someone had typed the URL in the location bar of a web browser.
A php script could not be used like you imagine here. Because it's executed through apache after a request from somewhere.
Even if you do while(1) in your script, apache/php will automaticly stop your script.
Responding to your comment, yes you'll need ssh access to do this, except if your web interface allow you to add cronjob.
Maybe you can write a service which can be executed with a program on another server and do the job.
If you have no access to the server the easiest way would probably be to hit it through the browser, but that would require you or an external script hitting the URL at the same interval each day when you wanted it to one. You may also be able to setup a Selenium test suite that runs locally on a schedule and hits the page. I'm not 100% if that's possible with Selenium though, you may need some 3rd-party apps to make it happen.
Something else you could try would be to see about using PHP's Process Control Functions (link). These will let you create a script that is a deamon and runs in the background. You may be able to do this to keep the script running on the server and firing off commands at programmed intervals. You will still need some way to get it running the first time (browser request or via command line) though.