I recently installed Solarium (with Java 8 on Ubuntu 14.04, PHP 5.5).
I created a core called test :
$ sudo -u solr /opt/solr-6.5.1/bin/solr create -c test
Then I indexed in it the "techproducts" example :
$ bin/post -c test example/exampledocs/*.xml
So I then tried to execute a PHP file given as an example with Solarium. In SSH I do :
$ php 1.2-basic-select.php
And it works, it shows the content indexed.
But, when I open this same PHP file with a browser, I've got an error :
Fatal error: Uncaught exception 'Solarium\Exception\RuntimeException' with message 'cURL is not available, install it to use the CurlHttp adapter' in /var/www/html/cvrecruteur.com/slr/vendor/solarium/solarium/library/Solarium/Core/Client/Adapter/Curl.php:228
Curl and php-curl are installed and up to date so I don't really know what's the deal here.