Warning: Use of undefined constant OAUTH_REQENGINE_CURL

On an Ubuntu server (Ubuntu 20.04.2 LTS) when running a PHP script, I get the following error.

Warning: Use of undefined constant OAUTH_REQENGINE_CURL - assumed 'OAUTH_REQENGINE_CURL' (this will throw an Error in a future version of PHP

On checking phpinfo, I get

Ubuntu PHP OAuth

Request engine support	php_streams

curl is missing in “Request engine support”.

This is because the default php-oauth package does not support curl. To fix, uninstall php-oauth and install oauth package using pecl.

Uninstall pcel

apt install php-oauth -y

install curl dev package

apt install libcurl4-gnutls-dev
ln -s /usr/include/x86_64-linux-gnu/curl /usr/include/curl

Install PHP PECL

apt install php-pear

Install oAuth

pecl install oauth

Edit php.ini file

vi /etc/php/7.4/cli/php.ini

Add at end of the file

extension=oauth.so

You need to do the same for Apache and php-fpm php.ini files located at

/etc/php/7.4/apache2/php.ini
/etc/php/7.4/fpm/php.ini

7.4 is for PHP version 7.4. Change this to whatever PHP version you have on your server. After making the change, phpinfo() page shows curl

ubuntu php oauth

See php