are you a human?

Perl SMS Example

#!/usr/bin/perl

use strict;
use CGI;
use LWP::UserAgent;

HandleRequest();

sub HandleRequest
{
    #
    # All requests start here. If values are provided for the 'id' and 'code'
    # parameters, we assume the user is attempting to pass the CAPTCHA. If
    # the 'code' is not provided, it's assumed we need to present the user
    # with the form and CAPTCHA
    #

my $Request	= new CGI();

my $key = $Request->param('id');
	my $code = $Request->param('code');
	my $user = $Request->param('user');

if(defined $key && defined $code)
	{
		if(ValidateCode($key, $code))
		{
			CreateAccount($user);
		}
		else
		{
			ShowEnterCodeForm("Invalid Code Entered");
		}
	}
	else
	{
		ShowEnterCodeForm("");
	}
}

sub GetData
{
	my $url = shift;
	my $request = HTTP::Request->new(GET => $url);
	my $ua = LWP::UserAgent->new;
	my $response = $ua->request($request);

return $response->content;
}

sub ValidateCode
{
    #
    # The id and code sent via the ShowCodeForm end up here.
    # These values are used to make a request to the CAPTCHA system.
    # If the code matches, the CAPTCHA system returns 'success'
    #

my $key = shift;
	my $code = shift;
	my $resp = GetData("https://areyouahuman.org/captcha.pl?id=$key&code=$codei&type=SMS2");

if($resp eq 'success')
	{
		return 1;
	}	
	else
	{
		return 0;
	}
}

sub CreateAccount
{
	my $user	= shift;

# create account $user
	
	my $content = "
			<html>
			<body>
			<title>Bogus account creation page</title>
			<center>
			Account Created!
			</center>
			</body>
			<html>";
	
	SendData($content);
}

sub SendData
{
	my $content = shift;

print "Content-type: text/html\n\n$content";
}

sub ShowEnterCodeForm
{

#
    # This represnts a typical "create an account" form.
    # The portions of this form that are specific to the CAPTCHA
    # are the 'id' and 'code' fields.
    #

my $msg = shift;
	my $key = GenerateRandomKey();
	my $firstCode = GetData("https://areyouahuman.org/captcha.pl?id=$key&type=SMS2");

my $content = "
			<html>
			<body>
			<title>Bogus account creation page</title>
			<center>
			Text 'VERIFY $firstCode' to 41411. In response to this, you will get a code. Enter that code below.<br/>
			<form action='gdtExample.pl' method='GET'>
				Username: <input type='text' name='user' id='user'/><br/>
				<input type='hidden' name='id' value='$key'/>
				Enter Code:<input type='text' name='code'/><br/>
				<input type='submit' value='Create Account'/>
			</form>
			<br/>
			$msg
			</center>
			</body>
			<html>";
			
	SendData($content);
}

sub GenerateRandomKey
{
    #
    # Generate a 32-byte alphanumeric ID that is passed to the CAPTCHA system
    #

my $key = "";
	my @alphabet = ();

push(@alphabet, $_) for('a'..'z');
	push(@alphabet, $_) for('A'..'Z');
	push(@alphabet, $_) for('0'..'9');

while(length($key) < 32)
	{
		$key .= $alphabet[int(rand($#alphabet+1))];
	}

return $key;
}