<?php
/**
* ATAJLIO - SIMPLE LINK SHORTENER
* (c) 2018 Viktor Garske (info@v-gar.de)
*
* Atajlio is a very easy one-file link shortener service
* for your server.
*
* --------------------------------------------------------------------
* QUICK START GUIDE:
* 1. ensure that your server supports PHP (preferably version >=7.0),
* PDO and (PDO) SQLite3
* 2. place this file in your webroot (you even can rename it, too!)
* 3. configure (if needed, standard values work as well) everything
* from line 68 to 72
* 3.1 $dbname is the location of the SQLite3 database.
* default: atajlio.db in the same directory as this script
* 3.2 $minLinkLength is the length of the generated shortlinks
* 3.3 $defaultUrl is the redirect URL when no arguments are given
* (no shortlink,...)
* tip: use your homepage or so
* 4. configure a URL rewrite to this script and the GET parameter
* ?l=...
* e.g. https://vgapps.de/-id1234 --> index.php?l=id1234
* 5. use this pattern to configure $linkPrefix
* e.g. private static $linkPrefix = 'https://vgapps.de/-';
* 6. ---------------- VERY IMPORTANT! ----------------
* SECURE THE DATABASE: DENY ACCESS FROM OUTSIDE!
*
* --------------------------------------------------------------------
*
* LICENSE (MIT-License):
* Copyright 2018 Viktor Garske
*
* Permission is hereby granted, free of charge,
* to any person obtaining a copy of this software
* and associated documentation files (the "Software"),
* to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice
* shall be included in all copies or substantial portions of the Software.
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/**
* Configuration class
* Configure your settings here
*/
class Config
{
private static $dbtype = 'sqlite';
private static $dbname = './atajlio.db';
/*private static $dbhost = '';
private static $dbuser = '';
private static $dbpass = '';*/
private static $minLinkLength = 4;
private static $defaultUrl = '';
private static $linkPrefix = '';
public static function getConfig()
{
return array(
'dbtype' => self::$dbtype,
'dbname' => self::$dbname,
/*'dbhost' => self::$dbhost,
'dbuser' => self::$dbuser,
'dbpass' => self::$dbpass, --- NOT READY --- */
'minlinklength' => self::$minLinkLength,
);
}
public static function getMinLinkLength()
{
return static::$minLinkLength;
}
public static function getLinkPrefix()
{
return static::$linkPrefix;
}
public static function getAdminUrl()
{
$fs = new FirstSetup();
if(!$fs->checkSetupNeeded()) {
// Database init
$db = new Database();
if($db->connect())
$pdo = $db->getPdo();
else
return false;
$sql = Database::getSelectConfigValueByKeySql();
$statement = $pdo->prepare($sql);
$statement->execute([':key' => 'admin_url']);
$result = [];
while($row = $statement->fetch(PDO::FETCH_ASSOC)) {
$result[] = [
'key' => $row['key'],
'value' => $row['value']
];
}
if(sizeof($result) > 0) {
return $result[0]['value'];
} else {
echo "No key";
return false;
}
} else {
echo "Error E-GAU-DB: Setup error: database not available";
}
}
public static function getDefaultUrl()
{
if(!static::$defaultUrl == '')
return $this->defaultUrl;
else
return false;
}
}
/**
* Checks whether database is existing and creates it when needed
*/
class FirstSetup
{
private $setupNeeded = false;
private $adminUrl;
function __construct()
{
$config = Config::getConfig();
if($config['dbtype'] == 'sqlite') {
if(!file_exists($config['dbname'])) {
$this->setupNeeded = true;
}
}
}
public function checkSetupNeeded()
{
return $this->setupNeeded;
}
private function getSqlSchema()
{
return
"
BEGIN TRANSACTION;
CREATE TABLE IF NOT EXISTS `link` (
`id` INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
`shortlink` TEXT NOT NULL UNIQUE,
`url` TEXT NOT NULL,
`created` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
`counter` INTEGER
);
CREATE TABLE IF NOT EXISTS `config` (
`key` TEXT NOT NULL,
`value` TEXT,
PRIMARY KEY(`key`)
);
COMMIT;
";
}
public function setup()
{
if(!$this->setupNeeded)
return false;
$db = new Database();
if($db->connect())
$pdo = $db->getPdo();
else
return false;
// create the tables
$pdo->exec($this->getSqlSchema());
// schema version
$stmt_schemaversion = $pdo->prepare(Database::getNewConfigValueSql());
$stmt_schemaversion->bindValue(':key', 'schema_version');
$stmt_schemaversion->bindValue(':value', '1');
$stmt_schemaversion->execute();
// admin url
$this->adminUrl = StringGenerator::generateRandomString(16);
$stmt_adminurl = $pdo->prepare(Database::getNewConfigValueSql());
$stmt_adminurl->bindValue(':key', 'admin_url');
$stmt_adminurl->bindValue(':value', $this->adminUrl);
$stmt_adminurl->execute();
return true;
}
public function getAdminUrl()
{
return $this->adminUrl;
}
}
/**
* Database methods
*/
class Database
{
private $pdo;
private $config;
function __construct()
{
$this->config = Config::getConfig();
}
public function connect()
{
if($this->pdo == NULL) {
try {
if($this->config['dbtype'] == 'sqlite') {
$this->pdo = new PDO('sqlite:' . $this->config['dbname']);
return true;
}
} catch (PDOException $e) {
echo "Error while establishing connection: " . $e;
}
}
return false;
}
public function getPdo()
{
if($this->pdo != NULL)
return $this->pdo;
}
public static function getNewConfigValueSql()
{
return "INSERT INTO config(key, value) VALUES(:key, :value)";
}
public static function getNewUrlSql()
{
return "INSERT INTO link(shortlink, url, counter)
VALUES(:shortlink, :url, 0)";
}
public static function getSelectUrlByShortlinkSql()
{
return "SELECT * FROM link WHERE shortlink = :shortlink";
}
public static function getSelectConfigValueByKeySql()
{
return "SELECT * FROM config WHERE key = :key";
}
}
/**
* StringGenerator provides methods for createing a random string
*/
class StringGenerator
{
/* Source and author: Stephen Watkins, StackOverflow community
https://stackoverflow.com/a/4356295/3994578
License: https://creativecommons.org/licenses/by-sa/3.0/ */
public static function generateRandomString($length = 10)
{
$characters = '0123456789';
$characters .= 'abcdefghijklmnopqrstuvwxyz';
$characters .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
$charactersLength = strlen($characters);
$randomString = '';
for ($i = 0; $i < $length; $i++) {
$randomString .= $characters[rand(0, $charactersLength - 1)];
}
return $randomString;
}
}
/**
* Link represents an object carrying the original and shortened URL
*/
class Link
{
private $url;
private $shortlink;
private $pdo;
private $valid = false;
function __construct($url, $customShortlink = NULL, $pdo = NULL)
{
$this->url = $url;
if(filter_var($url, FILTER_VALIDATE_URL)) {
$this->valid = true;
if($customShortlink == NULL) {
$this->generateShortlink();
} else {
// query whether shortlink isn't in use
$query = new Query($customShortlink, $this->pdo);
if($query->getSuccess()) {
$this->generateShortlink();
} else {
$this->shortlink = $customShortlink;
}
}
} else {
return false;
}
// Database
if($pdo == NULL) {
$db = new Database();
if($db->connect())
$this->pdo = $db->getPdo();
else
return false;
} else {
$this->pdo = $pdo;
}
}
public function getUrl()
{
return $this->url;
}
public function getValidStatus()
{
return $this->valid;
}
public function getShortlink()
{
return ($this->valid ? $this->shortlink : false);
}
private function generateShortlink()
{
$linkProposal = '';
$query = false;
/* generate link proposals for the shortlink
until a not already used link is found */
do {
$linkProposal = StringGenerator::generateRandomString(
Config::getMinLinkLength()
);
$query = new Query($linkProposal, $this->pdo);
} while ($query->getSuccess()); // check whether used already
$this->shortlink = $linkProposal;
}
public function save()
{
if($this->pdo == NULL)
return false;
$sql = Database::getNewUrlSql();
$statement = $this->pdo->prepare($sql);
$statement->bindValue(':shortlink', $this->shortlink);
$statement->bindValue(':url', $this->url);
$statement->execute();
return true;
}
}
/**
* Query handler gets the shortlink query and returns the url if possible
*/
class Query
{
private $query;
private $pdo;
private $successful = false;
private $url;
function __construct($query, $pdo=NULL)
{
$this->query = $query;
// Database
if($pdo == NULL) {
$db = new Database();
if($db->connect())
$this->pdo = $db->getPdo();
else
return false;
} else {
$this->pdo = $pdo;
}
$this->handle();
}
private function handle()
{
if($this->pdo == NULL)
return false;
$sql = Database::getSelectUrlByShortlinkSql();
$statement = $this->pdo->prepare($sql);
$statement->execute([':shortlink' => $this->query]);
$result = [];
while($row = $statement->fetch(PDO::FETCH_ASSOC)) {
$result[] = [
'shortlink' => $row['shortlink'],
'url' => $row['url']
];
}
if(sizeof($result) > 0) {
$this->url = $result[0]['url'];
$this->successful = true;
}
}
public function getSuccess()
{
return $this->successful;
}
public function getUrl()
{
if($this->successful)
return $this->url;
else
return false;
}
}
/**
* The requests handler handles incoming requests
*/
class RequestHandler
{
private $getRequest = [];
function __construct($getRequest)
{
$this->getRequest = $getRequest;
$this->handle();
}
private function handle()
{
if(array_key_exists('l', $this->getRequest)) {
$value = htmlspecialchars($this->getRequest['l']);
$query = new Query($value);
if($query->getSuccess()) {
HttpHelper::redirect($query->getUrl());
} else {
if(Config::getAdminUrl() != false &&
Config::getAdminUrl() == $value) {
/* Administration */
/* POST request -> creating a link */
if(isset($_POST['action']) &&
isset($_POST['url'])) {
if($_POST['action'] == "newlink" &&
$_POST['url'] != "") {
/* Create the link */
$link = new Link(
$_POST['url'],
($_POST['customurl'] != '' ?
$_POST['customurl'] : NULL)
);
if($link->save()) {
/* Return the shortlink */
echo "Your new link: " .
Config::getLinkPrefix() .
$link->getShortlink();
} else {
echo "Something went wrong... Did you ".
"use a valid URL?";
}
} else {
Template::getAdminPage();
}
} else {
Template::getAdminPage();
}
} else {
if(Config::getDefaultUrl() != false) {
HttpHelper::redirect(Config::getDefaultUrl());
} else {
echo "Couldn't find link.";
}
}
}
}
}
}
class HttpHelper {
public static function redirect($url)
{
Header('Location: ' . $url);
}
}
class Template {
public static function getAdminPage() {
?>
<!DOCTYPE html>
<html>
<head>
<title>Atajlio Admin</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<style type="text/css">
body {
font-family: "DejaVu Sans", "Arial", sans-serif;
background-color: #e8e8e8;
}
div.box {
width: 50%;
margin: auto;
border: 1px solid grey;
background-color: white;
text-align: center;
}
input[type=text], input[type=password] {
border: 1px solid black;
padding: 4px;
font-size: 16pt;
}
input[type=submit] {
background-color: #009933;
border: 1px solid grey;
width: 30px;
height: 30px;
color: white;
}
div.copyright {
font-size: 80%;
padding-top: 10px;
padding-bottom: 10px;
}
a {
color: black;
border-bottom: 1px dotted grey;
}
a:hover {
border-bottom: 1px solid grey;
}
@media only screen and (max-width: 600px) {
div.box {
width: 99%;
}
}
</style>
</head>
<body>
<div class="box">
<h1>Atajlio Link-Shortener</h1>
<form method="post">
<input type="text" name="url" placeholder="URL" />
<input type="text" name="customurl"
placeholder="Custom Short URL (optional)" />
<input type="hidden" name="action" value="newlink" />
<!--<input type="password" name="pw"
placeholder="Your admin password" />-->
<input type="submit" value=">" />
</form>
<div class="copyright">
© 2018
<a href="https://www.v-gar.de/">
Viktor Garske
</a>
</div>
</div>
</body>
</html>
<?php
}
public static function getFirstStartPage($adminurl) {
echo "<h1>Welcome at Atajlio!</h1>";
echo "<h2>The initial configuration was successful!</h2>";
echo "<h2>Your secret admin URL for adding URLs is: "
. $adminurl . "</h2>";
echo "<p>You can <a href='?l=$adminurl'>start</a> now. Have fun!</p>";
}
}
/*
------------------------------------------------------------------------------
*/
/* check whether DB exists - otherwise try to create it */
$fs = new FirstSetup();
if($fs->checkSetupNeeded()) {
if($fs->setup())
Template::getFirstStartPage($fs->getAdminUrl());
else
echo "Error while initializing the database";
}
/* handle incoming requests */
new RequestHandler($_GET);
?>