cURL function instead of allow_url_fopen

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Enabling "allow_url_fopen" poses serious security risk and is disabled on Server. If enabled, allow_url_fopen allows PHP's file functions such as file_get_contents() and the include and require statements which can retrieve data from remote locations, like an FTP or web site.

If the developer do not using proper input filtering when passing user-provided data to these functions, it will lead to code injection vulnerabilities.

As an alternative, you may use cURL library for fetching external web pages

 

cURL is a command line tool for transferring files with URL syntax, supporting FTP, FTPS, HTTP, HTTPS, SCP, SFTP, TFTP, TELNET, DICT, FILE and LDAP. cURL supports HTTPS certificates, HTTP POST, HTTP PUT, FTP uploading, HTTP form based upload, proxies, cookies, user+password authentication (Basic, Digest, NTLM, Negotiate, kerberos...), file transfer resume, proxy tunneling and other useful tricks.

Please find the Examples of Coding with cURL :

Fetching a web page

<?php
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "http://example.com/");
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_exec($ch);
curl_close($ch);
?> 

Alternative for file_get_contents()

Instead of:

<?php
$file_contents = file_get_contents('http://example.com/');

// display file
echo $file_contents;
?>

Use this:

<?php
$ch = curl_init();
$timeout = 5; // set to zero for no timeout
curl_setopt ($ch, CURLOPT_URL, 'http://example.com');
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
$file_contents = curl_exec($ch);
curl_close($ch);

// display file
echo $file_contents;
?>

Otherwise if you are getting some errors with the code above, use this:

<?php
$site_url = 'http://example.com';
$ch = curl_init();
$timeout = 5; // set to zero for no timeout
curl_setopt ($ch, CURLOPT_URL, $site_url);
curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);

ob_start();
curl_exec($ch);
curl_close($ch);
$file_contents = ob_get_contents();
ob_end_clean();

echo $file_contents;
?>

Getting binary data

Images

This script retrieves a remote image and assigns the binary data to the variable $image, before outputting the image to the browser:

<?php
$image_url = "http://example.com/image.jpg";
$ch = curl_init();
$timeout = 0;
curl_setopt ($ch, CURLOPT_URL, $image_url);
curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);

// Getting binary data
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1);

$image = curl_exec($ch);
curl_close($ch);

// output to browser
header("Content-type: image/jpeg");
print $image;
?>

Alternative for file()

Instead of:

<?php
$lines = file('http://example.com/');

// display file line by line
foreach($lines as $line_num => $line) {
    echo "Line # {$line_num} : ".htmlspecialchars($line)."<br />\n";
}
?>

Use this:

<?php
$ch = curl_init();
$timeout = 5; // set to zero for no timeout
curl_setopt ($ch, CURLOPT_URL, 'http://example.com');
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
$file_contents = curl_exec($ch);
curl_close($ch);
$lines = array();
$lines = explode("\n", $file_contents);

// display file line by line
foreach($lines as $line_num => $line) {
    echo "Line # {$line_num} : ".htmlspecialchars($line)."<br />\n";
}
?>

Wrapping it all in an easy class

Use the following class to make reading/saving remote files easy. This class will automatically delete the temp files downloaded at the end of your PHP script.

<?php

class downloader {
    var $tempFolder;
    var $tempFiles = array();

    function __destruct () {
        foreach ($this->tempFiles as $file) {
            unlink($file['temp']);
        }
    }
    
    function __construct ($temp)
    {
        $this->tempFolder = $temp;
    }
    
    function get ($url) {
        array_unshift($this->tempFiles, array(
            'extension'=> array_pop(explode('.', $url)),
            'original'=> basename($url),
            'temp'=> $this->tempFolder . md5(microtime()),
        ));
        $ch = curl_init($url);
        $fp = fopen($this->tempFiles[0]['temp'], 'w');
        curl_setopt($ch, CURLOPT_FILE, $fp);
        curl_setopt($ch, CURLOPT_HEADER, 0);
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
        curl_exec($ch);
        curl_close($ch);
        fclose($fp);
        return $this->tempFiles[0]['temp'];
    }
    
    function read ($index = 0) {
        return file_get_contents($this->tempFiles[$index]['temp']);
    }
    
    function readArray ($index = 0)
    {
        return file($this->tempFiles[$index]['temp']);
    }
    
    function listFiles () {
        return $this->tempFiles;
    }
    
    function save ($path, $index = 0) {
        copy($this->tempFiles[$index]['temp'], (is_dir($path) ? $path . $this->tempFiles[$index]['original'] : $path));
    }
}

$d = new downloader('/home/<username>/<temp folder>');

?>

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