PHP show return from python script

Question

I am unable to get php to show full results of my python script, only the last basic print statement is printed. What am I doing wrong here? Why is the php not showing the output from the python script?

php

$result = exec('python list.py');
echo $result;

list.py

import subprocess
print "start"
a = subprocess.Popen(["ls", "-a"], stdout=subprocess.PIPE)
a.wait()
result_str = a.stdout.read()
print result_str
print "stop"

the command line output for that python script is as below

start
...filename
...filename
...etc...etc
stop

The php output from executing the python script is only

stop

Thank you

Answer 1

You need to pass $result as a param into exec() otherwise you only get the last statement.

exec('python list.py', $result);
print_r($result);

This will get an array of output, $result[0] will contain stop and $result[sizeof($result)-1] will contain stop and everything in between will contain the rest of your program output.

• Anthony: This using print_r($result); shows me Start and ($result[0]) shows me S, but ($result[-1]) shows me nothing. print_r($result[sizeof($result)-1]); shows me S
• Jonathan: @Anthony please re-read what I wrote. It seems you're still doing $result = exec('python list.py'); instead of exec('python list.py', $result);
• Anthony: Doing it as written exec('python list.py', $result); print_r($result[0]); and I get the results as stated above
• Jonathan: I've tested and confirmed that the only way you're getting this is if you're still doing $result = exec('python list.py'); OR $result = exec('python list.py', $result);. The exact code I provided works as expected.

Answer 2

exec will always return the last line from the result of the command. So, if you need to get every line of output from the command executed. Then, you need to write as below :

$result = exec('python list.py', $ouput);
print_r($output)

As per exec documentation

string exec ( string $command [, array &$output [, int &$return_var ]] )

If the output argument is present, then the specified array will be filled with every line of output from the command. Trailing whitespace, such as \n, is not included in this array. Note that if the array already contains some elements, exec() will append to the end of the array. If you do not want the function to append elements, call unset() on the array before passing it to exec().