Mongrel2 Binding For Go

This package provides you with the code needed to write handlers for mongrel2 in go. This package can be used separately from Seven5, but that would be a mistake, no?

This package assumes that you have already installed mongrel2 version 1.7.5+, the 0mq library version 2.1+, and the 0mq support for go.

Design

This is the mongrel2 layer. Most Seven5 developers can safely ignore this layer as it is pretty "raw" (like a steack tartare kinda raw).

There are two important interfaces in this package, HttpHandler and JsonHandler that can respond to mongrel2 messages for (implementation of) HTTP requests and Json requests, respectively. Each of these has an implementation of basic functionality called HttpHandlerDefault and JsonHandlerDefault, respectively. These particular implementations know how to correctly Bind() to mongrel server--thus allocating resources like ZMQ sockets--and how to Shutdown() which does the reverse. The two interfaces (and their implementations) know the particulars of the communication format that they should use with mongrel2. For example the HttpHandlerDefault knows about HttpRequest and HttpHandlerResponse

There is an interface RawHandler and a corresponding simple implementation called RawHandlerDefault that should never be needed by developers. It exists only to share code between the JS and HTTP code and thus avoid repetition. Note that the implementations of HttpHandlerDefault and JsonHandlerDefault include the implementation of RawHandlerDefault. This is what you want. If you had a composite that included the implementation of both HttpHandlerDefault and JsonHandlerDefault it would need, and would have, four sockets for mongrel2 communication--since mongrel two considers these "different handlers" from its point of view.

Based on effective go we expect you to use mongrel2.HttpRequest and http.Request to differentiate the mongrel2 specific version from similar, but different, other types.

Install

You must have your go environment variables, such as GOROOT set.

Go into the src/pkg/mongrel2 and do make install to install the mongrel2 library into your go repository of packages.

Go into the src/cmd/ directory and do make to build an example program. The program expects that you have previously configured mongrel2 to expect a hadler like this:

handler_test = Handler(	send_spec='tcp://127.0.0.1:10070',Makefile
	                   	send_ident='34f9ceee-cd52-4b7f-b197-88bf2f0ec378',
              	     	recv_spec='tcp://127.0.0.1:10071',
						recv_ident='') 

You also need to map that handler to a path. Using the example configuration file that comes with mongrel2, this would be something like this:

hosts = [
    Host(name="localhost", routes={
        '/tests/': Dir(base='tests/', index_file='index.html',default_ctype='text/plain')
    '/handlertest': handler_test
    })
]

Running

Make sure mongrel2 is running. We'll assume it's running on port 6767.

Running the mongrel_raw executable. You should see

waiting on a message from the mongrel2 server...

Fire a up a browser and point it at http://localhost:6767/handlertest/foo, assuming you are using the test configuration that comes with mongrel2 plus the configuration info above. You should a message in the browser window plus some output on the command line indicating that mongrel_raw responded to the request.

The mongrel_raw program only sends a single response to a single request. Thanks to 0mq, you can kill and restart handlers anytime while leaving mongrel2 running. You don't need to worry about startup order either..

If you want to see an example with several workers (goroutines) implementing the handler, you want to run the mongrel_workers handler. Sadly, you have change the Makefile to make it build mongrel_workers instead of mongrel_raw.

If you run that executable, you can send multiple requests to the handler and you will see in the browser results that there are different goroutines responding, and in round-robin fashion. ment variables.