So right now, i am attempting to enable php-curl within my apache2 server on Ubuntu 18.04 to allow an iframe to display an external site page. i have been using methods to attempt this that i have found documented in several places:

StackOverflow: How do I install the ext-curl extension with PHP 7?

StackOverflow: install cURL in php 7 (ubuntu14.04)

LinuxConfig.org: How to enable and disable PHP curl module with Apache on Ubuntu Linux

No matter what i seem to do, i cannot get anything sort of curl-related commands to work within php, which is very frustrating. i have ensured that i have used sudo apt-get install curl php7.2-curl which installed without issue, and have then restarted the apache service using sudo service apache2 restart. I have tried to enable the extension in the php.ini using extension=php_curl.dll, and also extension=curl, with no luck. If i try the code given on linuxconfig.org to check the curl module state, it says its disabled.

If i try running my php code, i find in my logs:

PHP Fatal error: Uncaught Error: Call to undefined function curl_init() in /var/www/html/inc.redirect.php:4\nStack trace:\n#0 {main}\n thrown in /var/www/html/inc.redirect.php on line 4

The code in my 'inc.redirect.php' file is as follows:

if (isset($_GET['url'])) {
    $url = $_GET['url'];
    $ch = curl_init();
    $timeout = 10;
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
    $data = curl_exec($ch);
    echo $data;

What am i doing wrong/missing?

UPDATE: looking in the apache2 error.log when i restart the service, i see the following:

PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php/20160303/curl.so' - /usr/lib/php/20160303/curl.so: cannot open shared object file: No such file or directory in Unknown on line 0

Still attempting to dig more into this, and it appears that the curl.so file its looking for is located in '/usr/lib/php/20170718'. What do i have to do to change the php config to look in the proper directory?

2 Answers 2


Found the issue.

What was happening was I had both php7.1 and php7.2 enabled within apache2. had to run sudo a2dismod php7.1, restart apache, and afterwards I was able to load my inc.redirect.php page without errors.

  • 1
    Awesome. Wow. Been searching for this one for hours. Working now. My problem was proxied images in Rainloop webmail not showing up on a particular server. Now they are.. however a couple still do not show and if I 'Open Image in a New Tab' I get a 404 error... but I think that is another issue, probably not one having to do with this one. This problem arose after a system upgrade to next version of Ubuntu. Basically I had to a2dismod php7.0 and a2enmod php7.2 (the latter said it was already enabled though) Thank you!
    – jdmayfield
    Jun 26, 2019 at 9:59

Thanks MathewH, I was strugging for last 2 days but was not able to locate the error, as curl module was installed, php-curl extension was also installed, I was able to run the curl for a url in terminal, but when I run the curl_init() function in a PHP code, it would always show 500 internal server error,

Though I have installed the curl module by following commands:

sudo apt-get install php7.0-curl
sudo /etc/init.d/apache2 restart

as I have php 7.4.6 installed in my system

Then I checked the Apache2 error logs in /var/log/apache2/error_log and I found that curl_init() shows error

Call to undefined function curl_init()

Then searching on google I find the link: PHP: Check if cURL is enabled. which mentioned these 3 codes to check whether curl is loaded or not:

  1. if(function_exists('curl_init') === false)
     //curl_init is not defined
        //cURL not enabled
  2. //Check if "curl" can be found in the array of loaded extensions.
    if(in_array('curl', get_loaded_extensions()))
        //cURL module has been loaded
        //It has not been loaded. Use a fallback.
  3. if(extension_loaded('curl'))
        //the extension has been loaded

I have added these 3 code in index.php and named the project folder as curl-load-check. After running I found and got confirmed that the curl extension is not loaded.

Then finally I found this link: Cannot enable php-curl on Ubuntu 18.04 & PHP 7.2 and from the answer of MathewH, I found that php 7.2 and php 7.4 were both enabled in apache2. so I disabled php 7.2 by the following commands:

sudo a2dismod php7.2
sudo systemctl restart apache2 

and then finally I checked the php code for checking whether the curl extension is loaded as mentioned above in php codes, it showed finally the curl extension is loaded successfully. I checked now the curl_init() function used in php code is working now without any error. Thanks MathewH, after a lot of struggle, finally you saved my day

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