Determining if a URL exists

thekidscareya

How do I determine whether $URL exists?

$URL = "http://www.{$domain}/~{$dir}/";

Thanks.

sneakyimp

do you mean a local URL (on your machine) or a remote one?

thekidscareya

A remote one...I was thinking of using something like this


# Define Variables

$domain = "someone.com";
$dir = "home";

$URL1 = "http://www.{$domain}/~{$dir}/index.html";
$URL2 = "http://www.{$domain}/~{$dir}/index.cfm";
$URL3 = "http://www.{$domain}/~{$dir}/index.php";

# See if it exists

if ($URL1 OR $URL2 .... == "EXISTS"){
echo "The url exists.";
} else {
echo "The url doesn't exist.";
}

I would do something along the lines of that if there were a defined # ext for web pages...but there are soo many....like php3, cfm, html, htm, shtm, shtml, etc....that it wont be worth it.

sneakyimp

you might want to use fopen()...it works on remote files. some good sample code here:

http://www.php.net/manual/en/features.remote-files.php

thekidscareya

i shall test it with this

<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>

<body>
<?php
$domain = "phpbuilder.com";
$dir = "board";

$URL = "http://www.{$domain}/{$dir}/";

$file = fopen ($url, "r");
if (!$file) {
   echo "<p>Unable to open remote file.\n";
   exit;
} else {
	echo "Able to open remote file.";
	}

fclose($file);
?> 
</body>
</html>

EDIT: Tested it and got this

Unable to open remote file.

script doesn't work... 🙁

sneakyimp

i think php is case sensitive. i adjusted your code (url lowercase both times) and this worked for me:


$domain = "phpbuilder.com";
$dir = "board";
$url = "http://www.{$domain}/{$dir}/";

$file = fopen ($url, "r");
if (!$file) {
   echo "<p>Unable to open remote file.\n";
   exit;
} else {
    echo "Remote file exists</p>";
}
fclose($file);

the problem is that if the URL doesn't exist, an ERROR is thrown. You might want to turn down error reporting before you call this and then turn it back up. i'm not sure how to do that exactly.

cyb

A much easier way might be to use the does exist command like so:

$variable = file_exists("file.htm");

The $variable will return either a "1" ,which is true, or nothing(null) which is false. You would then use an If statement, like so:

$variable = file_exists("file.htm");
If ($variable == false ) Then {
do whatever yo want 🙂 ;
}

Hope this helps,

cyb

sneakyimp

i'm not sure, but i think file_exists() only works on local files. he explicitly stated this is about remote files.

it's worth a quick try to find out, though.

cyb

hmm, I thought it worked with remote ones too. Let me know if it works.

cyb

thekidscareya

I wanted to do this on remote files. All I actually need to see is if the following folder exists...really...let alone a file


$url = "http://www.{$domain}/{$dir}/";

sneakyimp

i'm not sure, but i don't think there's any way to determine if a folder exists on a remote server....if you access phpbuilders.com/boards then the web server is going to return a particular file. the approach i suggested would be able to make some kind of decision if no file was returned.

if there is no file associated with that folder, then you're going to get a permission error of some kind i think. it will probably depend on the server and its config and the .htaccess file or whatever.

i think there might be a way to do it with sockets, but not sure. sounds like we need some more powerful help on this thread.

thekidscareya

Hmm...I would have limited access on the remote server...

So I can rephrase the question (if worst comes to worse...which i hope not)...How can I check to see if a folder exists in

"/home/public_html/{$dir}/"

sneakyimp

try is_dir:

http://www.php.net/manual/en/function.is-dir.php

thekidscareya

tired it

<?php
$domain = "phpbuilder.com";
$dir = "board";

$URL = "http://{$domain}/~{$dir}/";


if(is_dir($URL)){
echo "$URL exists.";
} else {

echo "$URL does not exist or there's an error.";

}

?>

works great locally...doesnt work remotely

about a few posts earlier...same problem with the last thign...doesnt work remotely

<?php
$domain = "phpbuilder.com";
$dir = "board";

$URL = "http://{$domain}/~{$dir}/";


$variable = file_exists("$URL"); 
If ($variable == false )  { 
echo "$URL doesn't exist."; 
} else {
echo "$URL does exist";
} 


?>

Weedpacket

It's a URL. It doesn't refer to a file, or a directory (all right, "folder", if you want to call it that), it refers to a resource. It might be a file, or a directory, or a bathmat, but that's the server's problem, not yours.

As the manual page for [man]file_exists[/man] notes, it only works with some URL schemes, and only since PHP5. If you're not using PHP5, file_exists() won't be any use to you.

sneakyimp's earlier code works for me. To suppress the warnings in the event that the URL fails, use @fopen.

sneakyimp

mighty weedpacket is somewhat mystical. trust him. this is precisely the kind of powerful help i had in mind.

my previous code is a little strange...i was inconsistent with the html tags....maybe this is better:

$domain = "phpbuilder.com"; 
$dir = "board"; 
$url = "http://www.{$domain}/{$dir}/"; 

$file = fopen ($url, "r"); 
if (!$file) { 
   echo "<p>Unable to open remote file</p>\n"; 
   exit; 
} else { 
    echo "<p>Remote file exists</p>\n"; 
} 
fclose($file);

weedpacket, what does the @ mean?? error supressor? or something more profound.

Weedpacket

Originally posted by sneakyimp
weedpacket, what does the @ mean?? error supressor? or something more profound.

Yup, that's exactly what it means; the error control operator (to give it its proper name) suppresses any errors generated by the following expression. Obviously it can't suppress parse errors, but anything less (Warnings and Notices) it will quietly gobble. It is expected that the programmer is intending to handle the failure in some other fashion. (It will also gobble fatal error messages - in that situation the script would simply halt.)

thekidscareya

I'm using the script that sneakimp gave me earlier...and it seems to work now...Lemme try to intgrate it into what I wanted it to do.

<?php
$domain = "phpbuilder.com"; 
$dir = "board"; 
$url = "http://www.{$domain}/{$dir}/"; 

$file = fopen ($url, "r"); 
if (!$file) { 
   echo "<p>Unable to open remote file.\n"; 
   exit; 
} else { 
    echo "Remote file exists</p>"; 
} 
fclose($file);


?>

EDIT: I get this error now:

Warning: fopen(http://www.nasway.com/~joel/): failed to open stream: HTTP request failed! HTTP/1.1 404 Not Found in C:\apache\xampp\htdocs\paid\hosting.php on line 211

sneakyimp

you didn't add the @ operator to fopen like weedpacket said. try this:

<?
//$domain = "phpbuilder.com";
//$dir = "board";
$domain = "argoNOT.foo";
$dir = "NADDA";
$url = "http://www.{$domain}/{$dir}/";

$file = @fopen ($url, "r");
if (!$file) {
   echo "<p>Unable to open remote file</p>\n";
   exit;
} else {
    echo "<p>Remote file exists</p>\n";
}
fclose($file);

?>

KEEP IN MIND that if the directory actually does exist on the other server but has no files inside it that you will get a "does not exist" message with this function. in the case where the directory exists but there is no file inside it--or more specifically there is no file inside which the server is instructed to serve up--then this function will return the false message.