php exec() of a python script

Question

i made this small php code to execute a python script i'll use but it returns an empty array. Python and php files are in the same directory and i am using VISTA. Python script is supposed to receive a string representing the information in a file, so in the exec() i simulated that. In the commmand line it works fine and prints in this example:

content-type: text/html

Smiles

php file

$out=''
exec("python convert_str.py Content-Type: text/html,,('ref', {'Asay_parameter': ['grfbg'], 'Smiles': ['535'], 'Cell_type': ['4t4t4'], 'Subcellular': ['4trgdf'], 'CAS': ['12233'], 'target_type': ['derj,.i'], 'LAB': ['4t4t'], 'Species': ['4t34t4'], 'Bio_target': ['vgery4'], 'strain': ['wde'], 'Unity': ['htht5u'], 'Tissue': ['kukl'], 'value': ['gjyy'], 'Observations': ['gergh'], 'Experimental_error': ['tht56'], 'InchI': ['2435d'], 'Comparisons': ['thyt5'], 'Assay_ID': ['hj6yu'], 'Conditions': ['345y4'], 'Institution': ['4t'], 'Mol_name': ['3r5rg']})",$out) ;
print_r($out);

python file:

#!C:\Python27\python.exe


print "Content-Type: text/html\n"

import sys
import ast
superstring= sys.argv[1:]


def join_strings(megastring):

    total=''
    for substring in superstring:        
        total+=substring
    return total


def convert(string):

    save=''
    count=0
    for c in string:

        if c=='{' :
            ini=count
        elif c=='}':
            end=count+1
        count+=1

    save+=string[ini:end]
    final = ast.literal_eval(save)

    return final

def mol_id_type(info_dict):

    if info_dict['Smiles']!='':
        return 'Smiles'
    elif info_dict['InchI']!='':
        return 'InchI'
    else:
        return 'CAS'

def mol_id(info_dict,tp):
    """returns the id itself"""
    return info_dict[tp]




large=join_strings(superstring)
dic=convert(large)
mol_type=mol_id_type(dic)
identification=mol_id(dic,mol_type)

print mol_type

Output of php:

array()

Answer 1

I am pretty sure that the method by which you feed your Python script with input data is flaky. Do not rely on the many levels of command line argument parsing/encoding/decoding. It is entirely possible that this is where the difference comes from that you observed, between command line (your shell, I guess) and calling Python from PHP via exec() .

Better pipe this data into your Python process (ie write it to stdin of the Python process, and read it from there), or write it to a file from within PHP and then read that file from Python. Doing so, so can be sure that nothing messes with the byte stream which is your input data.