functions.php

<?php

require_once 'config.php';
require_once 'mnemonic.php';

$url_pattern = '(([\w]+:)?\/\/)(([\d\w]|%[a-fA-f\d]{2,2})+(:([\d\w]|%[a-fA-f\d]{2,2})+)?@)?([\d\w][-\d\w]{0,253}[\d\w]\.)+[\w]{2,4}(:[\d]+)?(\/([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)*(\?(&amp;?([-+_~.\d\w]|%[a-fA-f\d]{2,2})=?)*)?(#([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)?';

$tag_pattern = '[a-zA-Z0-9_.-]+';
//preg compatible
$tag_url_preg = "/^$tag_pattern\|$url_pattern/";

function dbConnect()
{
    global $MYSQL_HOST, $MYSQL_USERNAME, $MYSQL_PASSWORD, $MYSQL_DATABASE;
    $db = mysql_connect($MYSQL_HOST, $MYSQL_USERNAME, $MYSQL_PASSWORD) or die("Error. Coudn't Connect to Database" . mysql_error());
    mysql_select_db($MYSQL_DATABASE, $db) or die("Error. Coudn't Select the Database: " . mysql_error());
    return $db;
}

function get_tag_url($uri)
{
    global $tag_url_preg;
    if (!preg_match($tag_url_preg, $uri))
        return false;
    else
        return explode('|', $uri, 2);
}
function valid_tag($uri)
{
    global $tag_pattern;
    global $max_tag_length;
    $tag_preg = "/^$tag_pattern$/";
    if (preg_match($tag_preg, $uri) && (strlen($uri) <= $max_tag_length))
        return true;
    else
        return false;
}
function valid_url($uri)
{
    global $url_pattern;
    $url_preg = "/^$url_pattern/";
    if (!preg_match($url_preg, $uri))
        return false;
    else
        return true;
}



function get_url_from_tag($tag)
{
    global $MYSQL_TABLE_REDIRECTIONS;
    $table = $MYSQL_TABLE_REDIRECTIONS;
    $query = "SELECT url FROM " . $table . " WHERE tag='" . mysql_real_escape_string($tag) . "';";
    $result = mysql_query($query);
    if ($result) {
        //should return array with only one row
        $url = mysql_fetch_assoc($result);
        //print_r($url);
        $no_of_url = count($url);
        if ($no_of_url == 0) {
            echo("This tag $tag doesn't have any URL associated with it");
            return false;
        } elseif ($no_of_url != 1) {
            die("This tag $tag didn't returned unique query. Please contact the website administrator");
            return false;
        } else {
            //increment the value of hits columns
            $query = "UPDATE $table SET hits = hits + 1 WHERE tag='$tag';";
            mysql_query($query) or die(mysql_error());
            
            //return the URL
            return $url['url'];
        }
    } 
    else {
        die("An error occured in retriving the URL for the tag $tag");
        return false;
    }
}
function register_url($url)
{
    global $tag_length;
    global $MYSQL_TABLE_REDIRECTIONS;
    global $logged_in;
    
    $newtag = mnemonic($tag_length, 0);
    //echo $newtag;
    $query = "SELECT url FROM " . $MYSQL_TABLE_REDIRECTIONS . " WHERE tag='" . mysql_real_escape_string($newtag) . "';";
    //echo $query;
    //exit();
    while (!mysql_query($query)) {
        //keep trying till a random tag which is not already in DB is found
        //TODO: A do-while loop would have been nicer
        $newtag = mnemonic($tag_length, 0);
        $query = "SELECT url FROM " . $MYSQL_TABLE_REDIRECTIONS . " WHERE tag='" . mysql_real_escape_string($newtag) . "';";
    }
    
    //now we have our tag, we have our URL, we have to get other information
    $tagger = "";
    if ($logged_in)
        $tagger = $_SESSION['OPENID_IDENTITY'];
    else
        $tagger = 'guest';
    
    $ipaddress = $_SERVER['REMOTE_ADDR'];
    $date_now = $mysqldate = date('Y-m-d H:i:s');
    $query = "INSERT INTO " . $MYSQL_TABLE_REDIRECTIONS . " value('$newtag','$url','$tagger','$ipaddress','$date_now',0);";
    if (mysql_query($query))
        return $newtag;
    else {
        die("Cannot insert into Database for URL: $url and tag:$newtag");
        return false;
    }
}

function register_url_tag($url, $tag)
{
    global $MYSQL_TABLE_REDIRECTIONS;
    //echo $newtag;
    $query = "SELECT url FROM " . $MYSQL_TABLE_REDIRECTIONS . " WHERE tag='" . mysql_real_escape_string($tag) . "';";
    if (mysql_num_rows(mysql_query($query))) {
        //echo "tag existed";
        return register_url($url);
    } 
    else {
        global $MYSQL_TABLE_REDIRECTIONS;
        global $logged_in;
        $tagger = "";
        if ($logged_in)
            $tagger = $_SESSION['OPENID_IDENTITY'];
        else
            $tagger = 'guest';
        
        $ipaddress = $_SERVER['REMOTE_ADDR'];
        $date_now = $mysqldate = date('Y-m-d H:i:s');
        $query = "INSERT INTO " . $MYSQL_TABLE_REDIRECTIONS . " value('$tag','$url','$tagger','$ipaddress','$date_now',0);";
        if (mysql_query($query))
            return $tag;
        else {
            die("Cannot insert into Database for URL: $url and tag:$tag");
            return false;
        }
    }
}


?>