Re: [Caml-list] Sample web server with nethttpd

[Gerd Stolpmann <info@gerd-stolpmann.de>]

Am Freitag, den 30.03.2007, 15:38 +0100 schrieb Joel Reymont:
> I'm trying to bring up a web app as soon as possible and failing to  
> link Ruby with OCaml code my choice is to decouple and put an app  
> server behind Rails. Apache is heavy-weight so mod_caml is out of the  
> question. The choice is nethttpd and Ocsigen.
> 
> My OCaml app server needs to take a POST request, grab the posted  
> source code, translate it and spit it out. I can't figure out how to  
> bring up a web server with nethttpd, though.
> 
> It would be extremely helpful to have an expanded nethttpd tutorial 
> [1] that included a sample web server. I read through but writing  
> efficient code to accept connections in OCaml seems daunting and the  
> choice between engine and reactor unclear.
> 
> There's a sample web server in the Netplex intro, though[2], is that  
> sufficient? Maybe the nethttpd intro should just point to the Netplex  
> one.

Yes, the Netplex one is fully sufficient, and this is the way to go
except you have very specific needs.

The Nethttpd modules more or less provide a construction kit for web
servers. Using them require a basic understanding how servers are
constructed in general. Sorry that I cannot give a recipe.

> Quoting the manual:
>  >>> Second, select an encapsulation.
> 
> How is this done, precisely?

Use either the reactor module or the engine module.

>  >>> As mentioned, the reactor is much simpler to use, but you must  
> take a multi-threaded approach to serve multiple connections  
> simultaneously.
> 
> What's the standard (optimal) pattern here? Are there any code samples?

You seem to be blind. There are examples.

>  >> The engine is more efficient, but may use more memory (unless it  
> is only used for static pages).
> 
> How much more memory? Is there a rule of thumb?

The engine needs memory buffers to store the incoming request. Depends
on the size of the requests. If you are not uploading files, you can
ignore that.

> How should I decide whether to pick an engine or a reactor?

Depends on what you can master. The engine is more difficult, you need
knowledge about event-based programming. If you don't have that
knowledge, keep away from it.

>  >>> Third, write the code to create the socket and to accept  
> connections.
> 
> Should I use the netplex intro sample code?

Don't know how to answer this. I cannot decide for you.

>  >>> For the reactor, you should do this in a multi-threaded way (but  
> multi-processing is also possible). For the engine, you should do  
> this in an event-based way.
> 
> It appears that web servers like Lighttpd use the event-based way,  
> should I pick that?

You find both approaches. Apache is multi-{processed,threaded}.

This mainly depends what you are also doing in your application.

Gerd
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