<?php
// MAKE SURE YOU HAVE A CONNECTION TO MYSQL... Or comment line 12 (and don't insert anything into your DB)
function valid($input){
    $input = trim($input);
    return isset($input) && $input!=null && $input!="";
}

function clean($input){
    if(get_magic_quotes_gpc()){
        $input = stripslashes($input);
    }
    $input = mysql_real_escape_string($input);
    $input = htmlentities($input, ENT_COMPAT, "UTF-8");
    return $input;
}

function done($msg){
    echo json_encode(array("message"=>$msg));
}

if(valid($_POST['message']) && valid($_POST['token'])){
    $msg = clean($_POST['message']);
    $token = clean($_POST['token']);
    if($token == "YourTokenHere"){ // This really should not be hardcoded
        // Post $msg to your site
        // Post $msg to Twitter
        done("Posted!");
    }else{
        done("Invalid Token");
    }
}else{
    done("Unclean Variables");
}
?>