| Queuing at job from within php program? [message #175666] |
Mon, 17 October 2011 13:24  |
bobmct
Messages: 16
Registered: September 2010
Karma: 0
|
Junior Member |
|
|
Fellow php'ers;
I'm having some difficulty getting this to work: Based on a date/time
selected by a user on a web form I would like to use the "at" command to
schedule that task.
I've tried various php functions (system, exec, passthru) with the same
results (return code 1 - which I cannot seem to get the error message
from).
Here is a sample code snippet:
$cmd = "echo \"podcast -c $filename\" | at $hr:$mn $_ampm";
passthru("$cmd", $Retcode);
echo "$Retcode";
returns 1
Then I thought that perhaps the 'at' was not reading stdin in this case
so I tried a temporary file approach:
$cmd = "echo \"podcast -c $filename\"";
file_put_contents($filename.tmp, $cmd);
passthru("at $_hr:$_mn $_ampm < $filename.tmp", $_RetVal);
echo "$_RetVal";
This time it returned 2
I've got to be misunderstanding this function. So, I thought if any of
you skilled readers have had luck with doing something like this you may
be willing to share. However, any other suggestions greatly appreciated.
Thanks
|
|
|
|
| Re: Queuing at job from within php program? [message #175667 is a reply to message #175666] |
Mon, 17 October 2011 15:20  |
Jerry Stuckle
Messages: 2598
Registered: September 2010
Karma: 0
|
Senior Member |
|
|
On 10/17/2011 9:24 AM, bobm3(at)worthless(dot)info wrote:
> Fellow php'ers;
>
> I'm having some difficulty getting this to work: Based on a date/time
> selected by a user on a web form I would like to use the "at" command to
> schedule that task.
>
> I've tried various php functions (system, exec, passthru) with the same
> results (return code 1 - which I cannot seem to get the error message
> from).
>
> Here is a sample code snippet:
>
> $cmd = "echo \"podcast -c $filename\" | at $hr:$mn $_ampm";
> passthru("$cmd", $Retcode);
> echo "$Retcode";
>
> returns 1
>
> Then I thought that perhaps the 'at' was not reading stdin in this case
> so I tried a temporary file approach:
>
> $cmd = "echo \"podcast -c $filename\"";
> file_put_contents($filename.tmp, $cmd);
> passthru("at $_hr:$_mn $_ampm< $filename.tmp", $_RetVal);
> echo "$_RetVal";
>
> This time it returned 2
>
> I've got to be misunderstanding this function. So, I thought if any of
> you skilled readers have had luck with doing something like this you may
> be willing to share. However, any other suggestions greatly appreciated.
>
> Thanks
What is actually in $cmd when you execute the passthru command?
What happens when you type this exact output at a command line prompt?
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex(at)attglobal(dot)net
==================
|
|
|
|
| Re: Queuing at job from within php program? [message #175668 is a reply to message #175667] |
Mon, 17 October 2011 15:51 |
bobmct
Messages: 16
Registered: September 2010
Karma: 0
|
Junior Member |
|
|
On Mon, 17 Oct 2011 11:20:38 -0400, Jerry Stuckle wrote:
> On 10/17/2011 9:24 AM, bobm3(at)worthless(dot)info wrote:
>> Fellow php'ers;
>>
>> I'm having some difficulty getting this to work: Based on a date/time
>> selected by a user on a web form I would like to use the "at" command
>> to schedule that task.
>>
>> I've tried various php functions (system, exec, passthru) with the same
>> results (return code 1 - which I cannot seem to get the error message
>> from).
>>
>> Here is a sample code snippet:
>>
>> $cmd = "echo \"podcast -c $filename\" | at $hr:$mn $_ampm";
>> passthru("$cmd", $Retcode);
>> echo "$Retcode";
>>
>> returns 1
>>
>> Then I thought that perhaps the 'at' was not reading stdin in this case
>> so I tried a temporary file approach:
>>
>> $cmd = "echo \"podcast -c $filename\"";
>> file_put_contents($filename.tmp, $cmd); passthru("at $_hr:$_mn $_ampm<
>> $filename.tmp", $_RetVal); echo "$_RetVal";
>>
>> This time it returned 2
>>
>> I've got to be misunderstanding this function. So, I thought if any of
>> you skilled readers have had luck with doing something like this you
>> may be willing to share. However, any other suggestions greatly
>> appreciated.
>>
>> Thanks
>
>
> What is actually in $cmd when you execute the passthru command?
>
> What happens when you type this exact output at a command line prompt?
I've echoed out the contents of $cmd in my testing. It does contain
exactly what is intended:
echo "podcast -c abc123 | at 10:01 am"
Also, the command I'm trying to execute works perfectly from the CLI with
the same (appropriate) values.
I'm thinking that there might be a permissions issue but I'm unable to
obtain the error message from the passthru command.
I suppose next I will try to create a small php script to emulate this
from the CLI and perhaps them I will see the error (if any).
Thanks
|
|
|
|
| Re: Queuing at job from within php program? [message #175669 is a reply to message #175668] |
Mon, 17 October 2011 16:47 |
Jerry Stuckle
Messages: 2598
Registered: September 2010
Karma: 0
|
Senior Member |
|
|
On 10/17/2011 11:51 AM, bobm3(at)worthless(dot)info wrote:
> On Mon, 17 Oct 2011 11:20:38 -0400, Jerry Stuckle wrote:
>
>> On 10/17/2011 9:24 AM, bobm3(at)worthless(dot)info wrote:
>>> Fellow php'ers;
>>>
>>> I'm having some difficulty getting this to work: Based on a date/time
>>> selected by a user on a web form I would like to use the "at" command
>>> to schedule that task.
>>>
>>> I've tried various php functions (system, exec, passthru) with the same
>>> results (return code 1 - which I cannot seem to get the error message
>>> from).
>>>
>>> Here is a sample code snippet:
>>>
>>> $cmd = "echo \"podcast -c $filename\" | at $hr:$mn $_ampm";
>>> passthru("$cmd", $Retcode);
>>> echo "$Retcode";
>>>
>>> returns 1
>>>
>>> Then I thought that perhaps the 'at' was not reading stdin in this case
>>> so I tried a temporary file approach:
>>>
>>> $cmd = "echo \"podcast -c $filename\"";
>>> file_put_contents($filename.tmp, $cmd); passthru("at $_hr:$_mn $_ampm<
>>> $filename.tmp", $_RetVal); echo "$_RetVal";
>>>
>>> This time it returned 2
>>>
>>> I've got to be misunderstanding this function. So, I thought if any of
>>> you skilled readers have had luck with doing something like this you
>>> may be willing to share. However, any other suggestions greatly
>>> appreciated.
>>>
>>> Thanks
>>
>>
>> What is actually in $cmd when you execute the passthru command?
>>
>> What happens when you type this exact output at a command line prompt?
>
> I've echoed out the contents of $cmd in my testing. It does contain
> exactly what is intended:
> echo "podcast -c abc123 | at 10:01 am"
>
> Also, the command I'm trying to execute works perfectly from the CLI with
> the same (appropriate) values.
>
> I'm thinking that there might be a permissions issue but I'm unable to
> obtain the error message from the passthru command.
>
> I suppose next I will try to create a small php script to emulate this
> from the CLI and perhaps them I will see the error (if any).
>
> Thanks
OK, when you enter that exactly from the CLI it works? Are you
executing it as root or another user?
Next: the home directory for the web server will be different than the
one from the CLI. Also, the web server will have different permissions.
Usually the web server user will not have permission to access the
atjobs directory (/var/spool/cron/atjobs on Debian).
Try su'ing (or sudo'ing) to the web server's id, change to the web
server's root directory and execute the command.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex(at)attglobal(dot)net
==================
|
|
|
|
| Re: Queuing at job from within php program? [message #175670 is a reply to message #175669] |
Mon, 17 October 2011 18:27 |
Robert Heller
Messages: 60
Registered: December 2010
Karma: 0
|
Member |
|
|
At Mon, 17 Oct 2011 12:47:08 -0400 Jerry Stuckle <jstucklex(at)attglobal(dot)net> wrote:
>
> On 10/17/2011 11:51 AM, bobm3(at)worthless(dot)info wrote:
>> On Mon, 17 Oct 2011 11:20:38 -0400, Jerry Stuckle wrote:
>>
>>> On 10/17/2011 9:24 AM, bobm3(at)worthless(dot)info wrote:
>>>> Fellow php'ers;
>>>>
>>>> I'm having some difficulty getting this to work: Based on a date/time
>>>> selected by a user on a web form I would like to use the "at" command
>>>> to schedule that task.
>>>>
>>>> I've tried various php functions (system, exec, passthru) with the same
>>>> results (return code 1 - which I cannot seem to get the error message
>>>> from).
>>>>
>>>> Here is a sample code snippet:
>>>>
>>>> $cmd = "echo \"podcast -c $filename\" | at $hr:$mn $_ampm";
>>>> passthru("$cmd", $Retcode);
>>>> echo "$Retcode";
>>>>
>>>> returns 1
>>>>
>>>> Then I thought that perhaps the 'at' was not reading stdin in this case
>>>> so I tried a temporary file approach:
>>>>
>>>> $cmd = "echo \"podcast -c $filename\"";
>>>> file_put_contents($filename.tmp, $cmd); passthru("at $_hr:$_mn $_ampm<
>>>> $filename.tmp", $_RetVal); echo "$_RetVal";
>>>>
>>>> This time it returned 2
>>>>
>>>> I've got to be misunderstanding this function. So, I thought if any of
>>>> you skilled readers have had luck with doing something like this you
>>>> may be willing to share. However, any other suggestions greatly
>>>> appreciated.
>>>>
>>>> Thanks
>>>
>>>
>>> What is actually in $cmd when you execute the passthru command?
>>>
>>> What happens when you type this exact output at a command line prompt?
>>
>> I've echoed out the contents of $cmd in my testing. It does contain
>> exactly what is intended:
>> echo "podcast -c abc123 | at 10:01 am"
>>
>> Also, the command I'm trying to execute works perfectly from the CLI with
>> the same (appropriate) values.
>>
>> I'm thinking that there might be a permissions issue but I'm unable to
>> obtain the error message from the passthru command.
>>
>> I suppose next I will try to create a small php script to emulate this
>> from the CLI and perhaps them I will see the error (if any).
>>
>> Thanks
>
> OK, when you enter that exactly from the CLI it works? Are you
> executing it as root or another user?
>
> Next: the home directory for the web server will be different than the
> one from the CLI. Also, the web server will have different permissions.
> Usually the web server user will not have permission to access the
> atjobs directory (/var/spool/cron/atjobs on Debian).
>
> Try su'ing (or sudo'ing) to the web server's id, change to the web
> server's root directory and execute the command.
On a *typical* (eg properly secured) LAMP server, the web server would
be running as the user 'apache' and the apache user's shell will be set
to '/sbin/nologin'. This means that the web server user cannot login to
a shell. This implies that you cannot fork() a *shell*:
sauron.deepsoft.com% sudo su apache -l
This account is currently not available.
In order to run an at command, you need to fork() a shell process.
--
Robert Heller -- 978-544-6933 / heller(at)deepsoft(dot)com
Deepwoods Software -- http://www.deepsoft.com/
() ascii ribbon campaign -- against html e-mail
/\ www.asciiribbon.org -- against proprietary attachments
|
|
|
|
| Re: Queuing at job from within php program? [message #175673 is a reply to message #175670] |
Mon, 17 October 2011 20:53 |
Jerry Stuckle
Messages: 2598
Registered: September 2010
Karma: 0
|
Senior Member |
|
|
On 10/17/2011 2:27 PM, Robert Heller wrote:
> At Mon, 17 Oct 2011 12:47:08 -0400 Jerry Stuckle<jstucklex(at)attglobal(dot)net> wrote:
>
>>
>> On 10/17/2011 11:51 AM, bobm3(at)worthless(dot)info wrote:
>>> On Mon, 17 Oct 2011 11:20:38 -0400, Jerry Stuckle wrote:
>>>
>>>> On 10/17/2011 9:24 AM, bobm3(at)worthless(dot)info wrote:
>>>> > Fellow php'ers;
>>>> >
>>>> > I'm having some difficulty getting this to work: Based on a date/time
>>>> > selected by a user on a web form I would like to use the "at" command
>>>> > to schedule that task.
>>>> >
>>>> > I've tried various php functions (system, exec, passthru) with the same
>>>> > results (return code 1 - which I cannot seem to get the error message
>>>> > from).
>>>> >
>>>> > Here is a sample code snippet:
>>>> >
>>>> > $cmd = "echo \"podcast -c $filename\" | at $hr:$mn $_ampm";
>>>> > passthru("$cmd", $Retcode);
>>>> > echo "$Retcode";
>>>> >
>>>> > returns 1
>>>> >
>>>> > Then I thought that perhaps the 'at' was not reading stdin in this case
>>>> > so I tried a temporary file approach:
>>>> >
>>>> > $cmd = "echo \"podcast -c $filename\"";
>>>> > file_put_contents($filename.tmp, $cmd); passthru("at $_hr:$_mn $_ampm<
>>>> > $filename.tmp", $_RetVal); echo "$_RetVal";
>>>> >
>>>> > This time it returned 2
>>>> >
>>>> > I've got to be misunderstanding this function. So, I thought if any of
>>>> > you skilled readers have had luck with doing something like this you
>>>> > may be willing to share. However, any other suggestions greatly
>>>> > appreciated.
>>>> >
>>>> > Thanks
>>>>
>>>>
>>>> What is actually in $cmd when you execute the passthru command?
>>>>
>>>> What happens when you type this exact output at a command line prompt?
>>>
>>> I've echoed out the contents of $cmd in my testing. It does contain
>>> exactly what is intended:
>>> echo "podcast -c abc123 | at 10:01 am"
>>>
>>> Also, the command I'm trying to execute works perfectly from the CLI with
>>> the same (appropriate) values.
>>>
>>> I'm thinking that there might be a permissions issue but I'm unable to
>>> obtain the error message from the passthru command.
>>>
>>> I suppose next I will try to create a small php script to emulate this
>>> from the CLI and perhaps them I will see the error (if any).
>>>
>>> Thanks
>>
>> OK, when you enter that exactly from the CLI it works? Are you
>> executing it as root or another user?
>>
>> Next: the home directory for the web server will be different than the
>> one from the CLI. Also, the web server will have different permissions.
>> Usually the web server user will not have permission to access the
>> atjobs directory (/var/spool/cron/atjobs on Debian).
>>
>> Try su'ing (or sudo'ing) to the web server's id, change to the web
>> server's root directory and execute the command.
>
> On a *typical* (eg properly secured) LAMP server, the web server would
> be running as the user 'apache' and the apache user's shell will be set
> to '/sbin/nologin'. This means that the web server user cannot login to
> a shell. This implies that you cannot fork() a *shell*:
>
> sauron.deepsoft.com% sudo su apache -l
> This account is currently not available.
>
> In order to run an at command, you need to fork() a shell process.
>
>
It depends on what you're doing. Many web servers allow you to fork a
command, for good reasons. Just because you can execute a command shell
doesn't mean it's not properly secured.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex(at)attglobal(dot)net
==================
|
|
|
|
| Re: Queuing at job from within php program? [message #175675 is a reply to message #175666] |
Tue, 18 October 2011 03:43 |
Denis McMahon
Messages: 634
Registered: September 2010
Karma: 0
|
Senior Member |
|
|
On Mon, 17 Oct 2011 13:24:27 +0000, bobm3 wrote:
> Fellow php'ers;
>
> I'm having some difficulty getting this to work: Based on a date/time
> selected by a user on a web form I would like to use the "at" command to
> schedule that task.
>
> I've tried various php functions (system, exec, passthru) with the same
> results (return code 1 - which I cannot seem to get the error message
> from).
>
> Here is a sample code snippet:
>
> $cmd = "echo \"podcast -c $filename\" | at $hr:$mn $_ampm";
> passthru("$cmd", $Retcode);
> echo "$Retcode";
>
> returns 1
>
> Then I thought that perhaps the 'at' was not reading stdin in this case
> so I tried a temporary file approach:
>
> $cmd = "echo \"podcast -c $filename\""; file_put_contents
($filename.tmp,
> $cmd); passthru("at $_hr:$_mn $_ampm < $filename.tmp", $_RetVal); echo
> "$_RetVal";
>
> This time it returned 2
>
> I've got to be misunderstanding this function. So, I thought if any of
> you skilled readers have had luck with doing something like this you may
> be willing to share. However, any other suggestions greatly
> appreciated.
>
> Thanks
Here's an example of calling a php file every minute to queue itself to
run again a minute later. Note that it uses a script file and a php file
Note that I've used "/path/" to indicate that on my system I used
absolute paths to define both files.
The script file calls the php file with the php cli processor:
--8<-- start /path/testit --8<--
#!/bin/bash
php /path/testit.php
--8<-- end /path/testit --8<--
and the php file executes a system call to schedule the script file:
--8<-- start /path/testit.php --8<--
<?php
system("at -m now +1 minutes -f /path/testit");
?>
--8<-- end /path/testit.php --8<--
I did notice that in my /etc/at.deny is an entry for my web server
process, so I guess that any attempt to invoke at from within the web
server would fail. I don't recall setting this, so it may be a default -
might be worth checking?
Rgds
Denis McMahon
|
|
|
|
| Re: Queuing at job from within php program? [message #175677 is a reply to message #175668] |
Tue, 18 October 2011 07:51 |
alvaro.NOSPAMTHANX
Messages: 277
Registered: September 2010
Karma: 0
|
Senior Member |
|
|
El 17/10/2011 17:51, bobm3(at)worthless(dot)info escribió/wrote:
>> What is actually in $cmd when you execute the passthru command?
>>
>> What happens when you type this exact output at a command line prompt?
>
> I've echoed out the contents of $cmd in my testing. It does contain
> exactly what is intended:
> echo "podcast -c abc123 | at 10:01 am"
This is the echo command. All it does is printing a string into the
standard output. PHP doesn't actually do much with your command; it
basically feeds the shell with it as-is. So before caring about
executing a command from PHP, you need to make sure that the command
itself works as expected.
--
-- http://alvaro.es - Álvaro G. Vicario - Burgos, Spain
-- Mi sitio sobre programación web: http://borrame.com
-- Mi web de humor satinado: http://www.demogracia.com
--
|
|
|
|
| Re: Queuing at job from within php program? [message #175678 is a reply to message #175666] |
Tue, 18 October 2011 08:12 |
Erwin Moller
Messages: 228
Registered: September 2010
Karma: 0
|
Senior Member |
|
|
On 10/17/2011 3:24 PM, bobm3(at)worthless(dot)info wrote:
> Fellow php'ers;
>
> I'm having some difficulty getting this to work: Based on a date/time
> selected by a user on a web form I would like to use the "at" command to
> schedule that task.
>
> I've tried various php functions (system, exec, passthru) with the same
> results (return code 1 - which I cannot seem to get the error message
> from).
>
<snip>
Others commented on the issues that can arrise with rights.
(More specific: the PHP-user (www-data or apache) adding tasks.)
I want to add another approach that I prefer.
(Written for Unix-lie systems. Replace cronjob with task-scheduler for
Windows.)
Personally I don't like my software to schedule new tasks automatically.
So if I need scheduling, I prefer to create 1 cronjob by hand, for
www-data, that runs a script (can be PHP).
That script than pulls from a database certain tasks WHEN they are needed.
Depending on the time-resolution you need you can run this cron-job once
a day, once an hour, every minute, etc.
I like it that way because I can catch the result, log the last time it
ran, etc. And e-mail myself or some admin in case of failure.
Just a thought. Maybe it helps in your situation.
If not, consider this noise. ;-)
Regards,
Erwin Moller
--
"That which can be asserted without evidence, can be dismissed without
evidence."
-- Christopher Hitchens
|
|
|
|
| Re: Queuing at job from within php program? [message #175687 is a reply to message #175678] |
Thu, 20 October 2011 01:40 |
bobmct
Messages: 16
Registered: September 2010
Karma: 0
|
Junior Member |
|
|
On Tue, 18 Oct 2011 10:12:13 +0200, Erwin Moller
<Since_humans_read_this_I_am_spammed_too_much(at)spamyourself(dot)com> wrote:
> On 10/17/2011 3:24 PM, bobm3(at)worthless(dot)info wrote:
>> Fellow php'ers;
>>
>> I'm having some difficulty getting this to work: Based on a date/time
>> selected by a user on a web form I would like to use the "at" command to
>> schedule that task.
>>
>> I've tried various php functions (system, exec, passthru) with the same
>> results (return code 1 - which I cannot seem to get the error message
>> from).
>>
>
> <snip>
>
> Others commented on the issues that can arrise with rights.
> (More specific: the PHP-user (www-data or apache) adding tasks.)
>
> I want to add another approach that I prefer.
> (Written for Unix-lie systems. Replace cronjob with task-scheduler for
> Windows.)
>
> Personally I don't like my software to schedule new tasks automatically.
> So if I need scheduling, I prefer to create 1 cronjob by hand, for
> www-data, that runs a script (can be PHP).
> That script than pulls from a database certain tasks WHEN they are needed.
> Depending on the time-resolution you need you can run this cron-job once
> a day, once an hour, every minute, etc.
>
> I like it that way because I can catch the result, log the last time it
> ran, etc. And e-mail myself or some admin in case of failure.
>
> Just a thought. Maybe it helps in your situation.
> If not, consider this noise. ;-)
>
> Regards,
> Erwin Moller
Thanks all for the great comments. I haven't looked at the at.deny
file yet but I will. Regarding the suggestion about storing the
request and triggering at defined intervals: that's my direction. But
seeing how I'm replacing a manual system now I need something to queue
these requests short-term while I find time to complete the back end.
Thanks again - Bob
|
|
|
|
|
|
Calendar
Search
Help
Members
Register
Login
Home
]