not able to execute nutch crawl command using php exec function - php

I have to run Nutch crawl commands using php exec but it shows
"0 Error: JAVA_HOME is not set"
The command works fine with terminal. I have tried the below code in crawl.php where apache-nutch-1.15 directory is placed.
exec('apache-nutch-1.15/bin/nutch inject crawl/crawldb urls',$output);
and this gives the above mentioned error.
Thank you in advance for any assistance you can provide.

In order to run Nutch you need the JAVA_HOME environment variable set and pointing to the proper path (where your JVM is installed). This works on your terminal because you have this variable set already. You can check this with:
$ env | grep JAVA
When a new process is started with exec from PHP, this environment variable is not set because it is not a shell, you're only starting a process without any "shell environment". You can use the putenv function to specify some environment variables before calling exec.

Related

Running complicated ROS shell command through php

I'm trying to run a ROS shell program on the server through php on Ubuntu 14.04. I have tried using system, exec, shell_exec but nothing happens and I don't get any output. The system call is the following:
echo shell_exec("/opt/ros/indigo/bin/rosrun gazebo_ros spawn_model -database Part_A -gazebo -model Part_A");
What are the limitations of using system or exec to run any shell command through php on a server?
I don't care as much about the output of the command as for its execution. I think the problem has to do with the fact that PHP doesn't have any PATH like shell does so it can't find any applications without specifying the exact location. How can I make PHP se the same PATH shell does?
The problem was that the apache user and the environment in which the bash commands are running are not set up correctly. I followed the instructions from this answer but instead of using "source" I used "." and instead of using the source.bash file I used the source.sh file. I also set all the environment variables that had to do with ros or gazebo using the putenv() function.

Using the `where` command through PHP

I am trying to get the path to certain exe's using the where command in the command prompt on windows.
Here is what i did in command prompt.
where g++
where java
where javac
where python
All of these are giving the correct output of the path in the console window which indicated that I have set the environment variables correctly.
But now When i try to run the commands using the shell_exec() function in PHP, only the call to where java and where python gives the correct output. I was even able to successfully execute a respective test file using these commands through PHP.
But strangely, where g++ and where javac give this error in the browser when run through PHP:
INFO: Could not find files for the given pattern(s).
Also if I get the outputs of these two commands on the console and then copy that into my script to compile a c++ or java file, it works perfect. But the where command returns the above INFO when run through the PHP script.
I am running the server on localhost using XAMPP. Any idea what is missing?

Calling specific version of python from PHP

I'm setting up a big system relying on python 2.7 being run through php. The call is always something like:
exec('python test.py');
However no matter what I do PHP keeps using python 2.4 for executing my files. Because of the size of the system I can't change in the programming, but will have to make 'python' point directly to python2.7.
By searching around I have reached the conclusion that I should change the php env.
echo getenv("PYTHONPATH"); // NOTHING
echo getenv("PATH"); // /bin:/usr/bin
I can do so through putenv (for example: putenv("PATH=/usr/bin/python2.7:".$_ENV["PATH"]), but php keeps running python 2.4 no matter what I change it to.
Hope somebody out there got a simple solution :)
Could you not just do this instead:
exec('/usr/bin/python2.7/python test.py');
another option, you can set path to interpreter in 1st line of script test.py
#!/usr/local/bin/python2.7
but you need make test.py executable
chmod +x path_to_file/test.py
and run from php as
exec('path_to_file/test.py');
P.S. be attentive administrators sometimes disable exec function on servers for safety.
disable_functions="popen,exec,system,passthru,proc_open,shell_exec" ....
If you can't use full path, try an alias:
alias python='/usr/bin/python2.7'
python --version
Python 2.7.2

export shell environment variable before running command from PHP CLI script

I have a script that uses passthru() to run a command. I need to set some shell environment variables before running this command, otherwise it will fail to find it's libraries.
I've tried the following:
putenv("LD_LIBRARY_PATH=/path/to/lib");
passthru($cmd);
Using putenv() doesn't appear to propagate to the command I'm running. It fails saying it can't find it libraries. When I run export LD_LIBRARY_PATH=/path/to/lib in bash, it works fine.
I also tried the following (in vain):
exec("export LD_LIBRARY_PATH=/path/to/lib");
passthru($cmd);
How can I set a shell variable from PHP, that propagates to child processes of my PHP script?
Am I limited to checking if a variable does not exist in the current environment and asking the user to manually set it?
I'm not 100% familiar with how PHP's exec works, but have you tried: exec("LD_LIBRARY_PATH=/path/to/lib $cmd")
I know that this works in most shells but I'm not sure how PHP doing things.
EDIT: Assuming this is working, to deal with multiple variables just separate them by a space:
exec("VAR1=val1 VAR2=val2 LD_LIBRARY_PATH=/path/to/lib $cmd")
You could just prepend your variable assignments to $cmd.
[ghoti#pc ~]$ cat doit.php
<?php
$cmd='echo "output=$FOO/$BAR"';
$cmd="FOO=bar;BAR=baz;" . $cmd;
print ">> $cmd\n";
passthru($cmd);
[ghoti#pc ~]$ php doit.php
>> FOO=bar;BAR=baz;echo "output=$FOO/$BAR"
output=bar/baz
[ghoti#pc ~]$
A couple things come to mind. One is for $cmd to be a script that includes the environment variable setup before running the actual program.
Another thought is this: I know you can define a variable and run a program on the same line, such as:
DISPLAY=host:0.0 xclock
but I don't know if that work in the context of passthru
https://help.ubuntu.com/community/EnvironmentVariables#Bash.27s_quick_assignment_and_inheritance_trick

command is not running from php script using shell_exec() or system() or exec() functions

I am working on Windows server and able to run command from command prompt
c:> %convertxls% {some args....}
But when I run same command from php script
*shell_exec(%convertxls% ..... 2>&1);*
it gives me error as
%convertxls% is not recognized as an internal or external command, operable program or batch file.
I think when I am running command from command prompt, it run for user which logged in. And when I run the php script it run for "www" user for which path is not set.
Can anybody tell me where I am doing mistake?
*Note: I haven't written complete command.
Supply the full path to the executable.
ignacio right,I wanted to add one more point that ignacio did not specify .
Check the parameter disable_functions in the php.ini .
maybe this function is not allowed.
This sounds like the environment variable %convertxls% is not set.
You can use putenv() to set it; alternatively, as Ignacio already says, specify the full path.

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