Install module that requires composer on server with only FTP I am working on website that only has restricted ftp access. Ya, no way around it.

I want to install the module PHPmailer, which uses composer to install libraries.

I have a local composer run dev site, from which I installed properly, then moved the module dir, and composer.json, composer.lock to the server, but when installing the module on the server I get the error 

Please install the PHPMailer library by executing 'composer update' in your site's root directory. (Currently using PHPMailer library version Missing).

Does composer update the database or what is going on here?

How can I easily install a module that made it self dependant on composer?
That error message is called from the modules install file.  It's checking to see if the PHPMailer class exists, and if not, let's you know the library needs to be installed before you can install the module.

If you successfully installed the module on your local dev site, then Composer downloaded the PHPMailer library to the root 'vendor' folder.  In the 'vendor' folder there should be a 'phpmailer' folder.  You just need to copy this folder over to your website's server (to it's root 'vender' folder) and then you should be able to install the module.