The SitePoint PHP blog has posted a new tutorial by Viraj Khatavkar showing how to use the phpseclib library to securely communicate with remote servers directly from your PHP code.

PHP has an SSH2 library which provides access to resources (shell, remote exec, tunneling, file transfer) on a remote machine using a secure cryptographic transport. Objectively, it is a tedious and highly frustrating task for a developer to implement it due to its overwhelming configuration options and complex API with little documentation.

The phpseclib (PHP Secure Communications Library) package has a developer friendly API. It uses some optional PHP extensions if they’re available and falls back on an internal PHP implementation otherwise. To use this package, you don’t need any non-default PHP extensions installed.

The first step is getting the library installed (via Composer) and a few example use cases including generating SSH keys dynamically and testing a SSH/SFTP connection. The tutorial then talks about three methods you can use with phpseclib to connect to remote servers: using an RSA key, using a password-protected RSA key and just the normal username/password combination. With the connection made they then show you how to:

• execute (single and multiple) commands on the remote server
• exit on the first error
• gather the output from the commands

There's also a bit included about some other interesting configuration options and a few alternatives to the library if phpseclib doesn't work exactly right for your application.