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Date:: Wed Aug 24 15:19:25 2022 UTC
Message:: Added additional error handling with hash collision
Actions:: History | Blame | Raw File
1 <?php
2 require_once './conf.php';
3 
4 define("SHORTER_NAME", "shortr");
5 define("SHORTER_VERSION", "v0.2");
6 define("CHARSET", "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789");
7 
8 $url = "";
9 $link = "";
10 $callback = "NO";
11 
12 
13 if (DEBUG == 'true') {
14         ini_set('display_errors', 1);
15         ini_set('display_startup_errors', 1);
16         error_reporting(E_ALL);
17 } else {
18         ini_set('display_errors', 0);
19         ini_set('display_startup_errors', 0);           
20 }
21 
22 function db_connect() {
23 	$dbh = new PDO('mysql:host='. DB_HOST . ';dbname='. DB_NAME , DB_USER, DB_PASS);
24 	return $dbh;
25 }
26 
27 function count_urls($dbh) {
28 	$sth = $dbh->query("SELECT COUNT(*) FROM ". DB_TABLE);
29 	return $sth->fetchColumn();
30 }
31 
32 function generate_short($url, $dbh) {
33 	if(!preg_match("/^((https?|ftp)[:\/\/].*\/{2,})/i",$url)) {
34 		return false;
35 	}
36 	if (substr($url, 0, strlen(BASE_URL)) == BASE_URL){
37 		return false;
38 	}
39 	if (!empty($_SERVER['HTTP_X_CLIENTIP'])) {
40 		$clientip = $_SERVER['HTTP_X_CLIENTIP'];
41 	} else {
42 		$clientip = $_SERVER['REMOTE_ADDR'];
43 	}
44 	$sth = $dbh->prepare("SELECT id FROM " . DB_TABLE . " WHERE url=?");
45 	$sth->bindParam(1, $url, PDO::PARAM_STR);
46 	$sth->execute();
47 	if ($row = $sth->fetch(PDO::FETCH_ASSOC)) {
48 		$hash = $row['id'];
49 	} else {
50 		$hash = substr(str_shuffle(CHARSET), 0, HASH_LENGTH);
51 		$sth = $dbh->prepare("SELECT COUNT(*) FROM " . DB_TABLE . " WHERE id=?");
52 		$sth->bindParam(1, $hash, PDO::PARAM_STR, HASH_LENGTH);
53 		$sth->execute();
54 		$loop = 0;
55 		while ($sth->fetchColumn() > 0) {
56 			if ($loop == 10) {
57 				$hash = "ERROR<br />Unable to create hash!";
58 				break;
59 			}
60 			$hash = substr(str_shuffle(CHARSET), 0, HASH_LENGTH);
61 			$sth->bindParam(1, $hash, PDO::PARAM_STR, HASH_LENGTH);
62 			$sth->execute();
63 			$loop++;
64 		}
65 		$sth = $dbh->prepare("INSERT INTO " . DB_TABLE . " (id, url, ip, count) VALUES (?, ?, ?, '0')");
66 		$sth->bindParam(1, $hash, PDO::PARAM_STR, HASH_LENGTH);
67 		$sth->bindParam(2, $url, PDO::PARAM_STR);
68 		$sth->bindParam(3, $clientip, PDO::PARAM_STR, 255);
69 		if (!$sth->execute()) {
70 			$hash = "ERROR<br />Failed to insert hash!";
71 		}
72 	}
73 	return $hash;
74 }
75 
76 function find_short($hash, $dbh) {
77 	$sth = $dbh->prepare("SELECT * FROM " . DB_TABLE . " WHERE id=?");
78 	$sth->bindParam(1, $hash, PDO::PARAM_STR, HASH_LENGTH);
79 	$sth->execute();
80 	if ($row = $sth->fetch(PDO::FETCH_ASSOC)) {
81 		$link = $row['url'];
82 		$sth = $dbh->prepare("UPDATE " . DB_TABLE . " SET count = count + 1 WHERE id=?");
83 		$sth->bindParam(1, $row['id'], PDO::PARAM_STR, HASH_LENGTH);
84 		$sth->execute();	
85 	} else {
86 		$link = false;
87 	}
88 	return $link;
89 }
90 
91 if (isset($_POST['url'])) {
92 	if ($_POST['url'] != '' && strlen($_POST['url']) > 0) {
93 		$db = db_connect();
94 		$link = generate_short($_POST['url'], $db);
95 	} else {
96 		$link = false;
97 	}
98 }
99 
100 if (isset($_GET['hash']) && $_GET['hash'] != '' && strlen($_GET['hash']) > 0) {
101 	$path = explode('/', $_SERVER['REQUEST_URI']);
102 	$uri = $path[count($path)-1];
103 	if ($uri != '') {
104 		$db = db_connect();
105 		$link = find_short($uri, $db);
106 		if ($link != '') {
107 			header("Cache-Control: no-cache, must-revalidate");
108 			header("Expires: Wed, 29 Feb 1984 00:00:00 GMT");
109 			header("Location: $link", TRUE, 301);
110 		}
111 	}
112 }
113 
114 if ($callback == 'NO') {
115 	$db = db_connect();
116 	$count = count_urls($db);
117 ?>
118 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
119 <html>
120 <head>
121 <title><?php print SITE_TITLE ?></title>
122 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
123 <meta name="keywords" content="shorter url tinyurl" /> 
124 <meta name="viewport" content="width=device-width, initial-scale=1" />
125 <style type="text/css" media="screen">
126 body {
127 	background: #282828;
128 	color: #ffffff;
129 	font-family: Arial,"MS Trebuchet",sans-serif;
130 	font-size: 14px;
131 	margin: 0;
132 	padding: 0;
133 	text-align: center;
134 }
135 
136 #container {
137 	width: 500px;
138 	margin: 0 auto;
139 	padding: 20px;
140 	display: block;
141 }
142 
143 #header {
144 	font-size: 20px;
145 	height: 100px;
146 	font-variant: small-caps;
147 }
148 
149 #content form input {
150 	width: 495px;
151 }
152 
153 #shorterurl_wrapper {
154 	width: 500px;
155 	height: 100px;
156 	border: 1px dashed;
157 	margin-top: 50px;
158 	background-color: #383838;
159 	text-align: center;
160 }
161 
162 #shorterurl {
163 	margin: 30px 30px 30px 30px;
164 	font-size: 25px;
165 	font-family: Verdana,Arial;
166 	font-weight: bold;
167 }
168 </style>
169 </head> 
170 </html>
171 <body>
172 <div id="container">
173 <div id="header">
174 <h1 id="shortertitle"><i><?php print SITE_TITLE ?></i></h1>
175 </div>
176 <div id="content">
177 <form id="shorterform" method="post">
178 <input id="url" type="text" name="url" value="<?php print $url ?>" />
179 </form>
180 <div id="shorterurl_wrapper">
181 <div id="shorterurl">
182 <?php 
183 	if ($link === false) {
184 		echo "<span style='color: red;'>Unknown / Invalid URL</span>"; 
185 	} elseif (str_contains($link, "ERROR")) {
186 		echo "<span style='color: red;'>$link</span>"; 
187 	} else {
188 		if ($link != '') {
189 			echo "<span style='color: white;'>" . BASE_URL . $link . "</span>";
190 		}
191 	}
192 ?>
193 </div>
194 </div>
195 </div>
196 <p>
197 <small>Currently holding <?php print "$count" ?> entries.<br /><br /><?php print SHORTER_NAME . " " . SHORTER_VERSION ?><br /></small>
198 </p>
199 </div>
200 </body>
201 </html>
202 <?php
203 }
204 ?>