Question

I am having trouble with NSProcessInfo's arguments property. I am creating a command line tool that needs to decode base64 code that it has been passed from the internet using a PHP script, along with some other arguments. The data is passed fine, but for some reason. [[NSProcessInfo processInfo] arguments] returns 21 arguments, even though I pass just one base64 string.

Here’s the objective-c side of it:

NSArray *arguments = [[NSProcessInfo processInfo] arguments];

if ([[arguments objectAtIndex:1] isEqualToString:@"-s"])
{
    if ([arguments objectAtIndex:2] == nil)
    {
        printf("Error: No data\n");
        [pool drain];
        return 0;
    }

    NSString*data = [arguments objectAtIndex:2];

    if ([data length] == 0)
    {
        printf("Error: No data\n");
        [pool drain];
        return 0;
    }

    NSString*password = @"";

    if ([[arguments objectAtIndex:3] isEqualToString:@"-p"])
    {
        if ([arguments objectAtIndex:4] == nil)
        {
            printf("Error: No password\n");
            [pool drain];
            return 0;
        }
        else
        {
            password = [NSString stringWithString:[arguments lastObject]];
        }
    }

NSLog(@"Args: %i\n\n",[arguments count]); //returns 21? I expect 3.

The base64 code is a bit long, so I’ve put it here. Does anyone know why this code returns this many arguments? It’s supposed to be just one string?
Edit: I am stripping whitespaces in my PHP script. See here:

<?php

$url = $_GET['data'];

$query = "/Library/WebServer/email/emailsender -s";
$password = "-p somePassword";

$commandStr = trim("$query $url $password");

$commandStr = removeNewLines($commandStr);

echo $commandStr;

$output = shell_exec($commandStr);

echo "<pre>Output: $output</pre>";

function removeNewLines($string) {

    $string = str_replace( "\t", ' ', $string );
    $string = str_replace( "\n", ' ', $string );
    $string = str_replace( "\r", ' ', $string );
    $string = str_replace( "\0", ' ', $string );
    $string = str_replace( "\x0B", ' ', $string );

    return $string;

}

?>

Answer 1

When you send arguments to a program through the command-line, each argument is separated by a whitespace character. This means that if you post a string that contains spaces, your program will interpret it as many arguments. To prevent this behavior, you need to quote your strings.