This tutorial demonstrates a simple, but non-trivial, example of a TCP proxy server using the OTP construct gen_server. The goal is to implement a process that can be used to deliver web services to HTML browsers. The source code is here.

This tutorial contains three parts:

1. A generic TCP proxy server based on gen_server
2. How to implement the ProxyModule interface
3. A Web Service using the TCP proxy server

Please, report all errors, omissions or improvements to the author.

1. Description of a proxy server
   1. The proxy server interface
   2. The gen_server behaviour
   3. Architecting a server design
   4. Implementing gen_server callbacks
   5. Implementing the Accept Connection process
2. ProxyModule explained
   1. Testing with an echo proxy server
   2. Echoing a browser request
   3. A proxy server to block websites
3. Deploying Web Services
   1. Recognizing requests
   2. Extracting from web pages
      1. Synonym dictionary
      2. Pattern matching dictionary
      3. Zoning a page
      4. Pulling content from a zone
   3. Reconstructing web pages

This portion of the tutorial has not yet been written.