We use Varnish between the client and our backend server. It helps to support more concurrent accesses to our website. However, you need to use the domain specific language "VCL" to define the cache policy. I don't like it much. I prefer writing Javascript. Nodish is a pure Javascript (node.js) solution to replace Varnish in your server.
There is only one single file in this project, server.js. The main proxy server logic is included in this file. There are also few pre-defined functions that help you build your own cache strategy. You may want to study each function to get to know what they are doing.
For a simple use case, you may just need to write your own cache logic in the function recv(). Yes. The naming strategy is a bit similar to Varnish such that you could be more familiar with the environment.
The cache logic that I am using in a production server is included for your reference. The arguments req and res are the request and response object provided by node.js. That means you can read/write any properties from/to them as you would do to other node.js application. (This is also why I prefer doing it in node.js instead of VCL)
There is a function called forwardRequest(). As the name suggested, it forwards the request to the backend server. At this moment, the request info is coded inside this function. You may need to change the host name and the port to fit your use case.
In my environment, I can start the server by this command.
sudo node server.jsThat simple. This starts a proxy server listening to port 80.
WTFPL is used. Do What The Fuck You Want To Public License
In short, you just DO WHAT THE FUCK YOU WANT TO.