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

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

See php