PHP, Check if URL and a file exists ? - php

Question

I create a plugin for WordPress that requires two files to be exists in order to operate normaly.
The first file is defined as a file system path and the second file is defined as a URL.
Let's say the first file is that:
/home/my_site/public_html/some_folder/required_file.php
and the second file is that:
http://www.my_site.com/some_folder/required_url_file.php
Note that both files are not the same file into the file system. The required_file.php has other content than the required_url_file.php and they act absolutly diferent
Any idea on how to validate the existance of both files ?

Answer 1

You can check both:
$file = '/home/my_site/public_html/some_folder/required_file.php';
$url = 'http://www.my_site.com/some_folder/required_url_file.php';
$fileExists = is_file($file);
$urlExists = is_200($url);
$bothExists = $fileExists && $urlExists;
function is_200($url)
{
$options['http'] = array(
'method' => "HEAD",
'ignore_errors' => 1,
'max_redirects' => 0
);
$body = file_get_contents($url, NULL, stream_context_create($options));
sscanf($http_response_header[0], 'HTTP/%*d.%*d %d', $code);
return $code === 200;
}

Answer 2

Based on Maor H. code sample, here is a function I am using in my plugins:
/**
* Check if an item exists out there in the "ether".
*
* #param string $url - preferably a fully qualified URL
* #return boolean - true if it is out there somewhere
*/
function webItemExists($url) {
if (($url == '') || ($url == null)) { return false; }
$response = wp_remote_head( $url, array( 'timeout' => 5 ) );
$accepted_status_codes = array( 200, 301, 302 );
if ( ! is_wp_error( $response ) && in_array( wp_remote_retrieve_response_code( $response ), $accepted_status_codes ) ) {
return true;
}
return false;
}
I've made this a method in a helper class, however putting this in your theme's functions.php file should make it generally accessible everywhere. However you should always be writing in classes and instantiating them. It is much better for isolating your plugin and theme functionality.
With this in place you can simply use:
if (webItemExists('http://myurl.com/thing.png')) {
print 'it iexists';
}
Most often you will be using WordPress calls to access all items via a relative or fully qualified URL. If you have a relative reference to something such as /uploads/2012/12/myimage.png you can convert those to a fully qualified URL v. a WordPress relative URL by simply adding get_site_url(). $string when calling the webItemExists() function.

Answer 3

As for validating the URL, none of these answers are considering the correct, WordPress way to carry out this task.
For this task wp_remote_head() should be used.
Here's an article I've written about How To Check Whether an External URL Exists with WordPress’ HTTP API. Check it out and figure out how it works.

Answer 4

$file_exists = file_exists($path);
$url_accessable = http_get($url, array("timeout"=>10), $info); // should not be FALSE
$status_code = $info['response_code'] //should be 200

Answer 5

This seems to work for me:
function url_file_exists($url) {
$context = stream_context_create(array('http' =>array('method'=>'HEAD')));
$fd = #fopen($url, 'rb', false, $context);
if ($fd!==false) {
fclose($fd);
return true;
}
return false;
}

Answer 6

If you have PECL http_head function available, you could check if it returns status code 200 for the remote file.
To check if you can access the local file, could use file_exists, but this does not grant that you will be able to access that file. To check if you can read that file, use is_readable.

Answer 7

To check if a file exists, use the file_exists method.
As of PHP 5.0.0, this function can also be used with some URL
wrappers. Refer to Supported Protocols and Wrappers to determine which
wrappers support stat() family of functionality.
if(! (file_exists($url1) && file_exists($url2)) ) {
die("Files don't exist - throw error here.");
}
// Continue as usual - files exist at this point.

Answer 8

remote:
$file = 'http://www.my_site.com/some_folder/required_url_file.php'
if ( #fclose(#fopen($file,"r")) ) echo "File exists!";
local:
$file = '/home/my_site/public_html/some_folder/required_file.php';
if ( is_file($file) ) echo "File exists!";

Answer 9

Use function file_exists()
file_exists('http://www.my_site.com/some_folder/required_url_file.php');
will get you results as True or false.

Answer 10

Checking if a file exists:
if (file_exists('path/to/file.txt')) {
echo "File exists!";
} else {
echo "File doesn't exist.";
}
Checking if a URL is valid:
$data = #file_get_contents("http://url.com/");
if (!$data) {
echo "URL not valid.";
} else {
echo "URL is valid.";
}
Notes:
Ideally you shouldn't try and predict the filesystem. Whilst methods such as file_exists are very helpful, they shouldn't be relied upon and instead you should attempt to write to files, read from them, etc, and then catch and handle any exceptions or errors that occur.