Cannot redeclare means either your include is being done more than once (solution: use include_once()) or that a class with that name already exists. To prevent that the namespaces exist. Also files in Laravel will automatically be loaded depending on namespaces by PSR-4 so if your class file is in the right place, is correctly named and has the right namespace you shouldn't have to worry about it.

Thanks.

Indeed i am trying to include the Mobile_Detect library(mobiledetect.net). In my controller i tried include_once() and got cannot redeclare, but note, if i only put this line of code:

$detect = new Mobile_Detect;

AND put the Mobile_Detect.php file in the same directory as the controller, i got cannot redeclare too...

Any idea?

Easy way: place the file somewhere in you app folder. Autoload it as file on your composer.json Not so Hard way: create a service provide to load the class(still you need to autoload your class)

why not use

https://github.com/jenssegers/agent

or

https://github.com/hisorange/browser-detect

they are specially made for laravel