Introduction #Introduction

allow_url_fopen is a filesystem and streams configuration option. Which enables the URL-aware fopen() wrappers that enable accessing URL objects like files.

If allow_url_fopen() is enabled then by default we can access remote files using the FTP or HTTP protocol.

Also, extensions like zlib may register additional wrappers.

---

Issue #Issue

We could not use the fopen() if the option allow_url_fopen is DISABLED from the server.

If it is enabled then you can disable it for testing purposes by adding code allow_url_fopen=Off in your php.ini file. Also, After updating the php.ini file don’t forget to restart the apache server.

Now, Let’s assume that we have below code in the file C:/xampp/htdocs/tutorials/index.php:

<?php
 if ( ini_get( 'allow_url_fopen' ) ) {
     echo "allow_url_fopen is ENABLED.\n";
 } else {    
     echo "allow_url_fopen is DISABLED.\n";
 }
 $file = fopen("http://www.example.com/", "r");

Note: We can use function ini_get() https://www.php.net/manual/en/function.ini-get.php to check the value of a server configuration. We have checked the value of allow_url_fopen as ini_get( 'allow_url_fopen' ). By default allow_url_fopen returns the boolean value.

We check the code by executing the PHP file with command line with below steps:

• Open terminal or command prompt.
• Goto C:/xampp/htdocs/tutorials/ with command cd C:/xampp/htdocs/tutorials/
• Now execute command php index.php

You can see something similar in your terminal window.

$ php index.php
allow_url_fopen is DISABLED.
PHP Warning:  fopen(): http:// wrapper is disabled in the server configuration by allow_url_fopen=0 in C:\xampp\htdocs\tutorials\index.php on line 9
PHP Stack trace:
PHP   1. {main}() C:\xampp\htdocs\tutorials\index.php:0
PHP   2. fopen() C:\xampp\htdocs\tutorials\index.php:9

Warning: fopen(): http:// wrapper is disabled in the server configuration by allow_url_fopen=0 in C:\xampp\htdocs\tutorials\index.php on line 9

Call Stack:
    0.4036     406560   1. {main}() C:\xampp\htdocs\tutorials\index.php:0
    0.4037     406592   2. fopen() C:\xampp\htdocs\tutorials\index.php:9

Variables in local scope (#1):
  $file = *uninitialized*

PHP Warning:  fopen(http://www.example.com/): failed to open stream: no suitable wrapper could be found in C:\xampp\htdocs\tutorials\index.php on line 9
PHP Stack trace:
PHP   1. {main}() C:\xampp\htdocs\tutorials\index.php:0
PHP   2. fopen() C:\xampp\htdocs\tutorials\index.php:9

Warning: fopen(http://www.example.com/): failed to open stream: no suitable wrapper could be found in C:\xampp\htdocs\tutorials\index.php on line 9

Call Stack:
    0.4036     406560   1. {main}() C:\xampp\htdocs\tutorials\index.php:0
    0.4037     406592   2. fopen() C:\xampp\htdocs\tutorials\index.php:9


Variables in local scope (#1):
  $file = *uninitialized*

The issue with Composer Update: #The issue with Composer Update:

If you try the composer update command then you can see something like below error:

MaheshW@DESKTOP-5E1INLB C:\xampp\htdocs\developer.wordpress.org\wp-content\plugins\phpdoc-parser
 $ composer update
 Loading composer repositories with package information
 The "https://repo.packagist.org/packages.json" file could not be downloaded: allow_url_fopen must be enabled in php.ini (https:// wrapper is disabled in the server configuration by allow_url_fopen=0
 failed to open stream: no suitable wrapper could be found)
 https://repo.packagist.org could not be fully loaded, package information was loaded from the local cache and may be out of date
 Updating dependencies (including require-dev)
 [Composer\Downloader\TransportException]
   The "http://repo.packagist.org/p/scribu/lib-posts-to-posts%24375806a5270591820170d67f4467d3f709c9e02e790b81753f82c8c15ea5cebd.json" file could not be downloaded: allow_url_fopen must be
   enabled in php.ini (http:// wrapper is disabled in the server configuration by allow_url_fopen=0
   failed to open stream: no suitable wrapper could be found)
 update [--prefer-source] [--prefer-dist] [--dry-run] [--dev] [--no-dev] [--lock] [--no-custom-installers] [--no-autoloader] [--no-scripts] [--no-progress] [--no-suggest] [--with-dependencies] [--with-all-dependencies] [-v|vv|vvv|--verbose] [-o|--optimize-autoloader] [-a|--classmap-authoritative] [--apcu-autoloader] [--ignore-platform-reqs] [--prefer-stable] [--prefer-lowest] [-i|--interactive] [--root-reqs] [--] []…

Fix/Solution #Fix/Solution

Open the php.ini file and search allow_url_fopen.

If you find it then change allow_url_fopen=Off with allow_url_fopen=On.

If you have not found the allow_url_fopen then simply add the allow_url_fopen=On.

After adding the allow_url_fopen=On our server support the fopen().

Now execute the same code as below:

$ php index.php
allow_url_fopen is ENABLED.

For more information visit: https://www.php.net/manual/en/filesystem.configuration.php#ini.allow-url-fopen

How to enable allow_url_fopen() from the php.ini file.

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