[Lispweb] Mod_lisp 2.0 released

John Foderaro jkf at franz.com
Tue Jun 19 13:57:08 CDT 2001

 Your list of advantages focused on the advantages of using mod_lisp
over having two independent web servers: Apache for static content
and a Lisp web server for dynamic content.

 Let's assume that we've decided to go with a shim model with some
standard web server out front and a Lisp application behind the scenes.
I'd like to see a list of concrete advantages of mod_lisp over mod_proxy.

 I'll give you some concete advantages of mod_proxy over mod_lisp:

1. Every major web server can do proxying.  mod_lisp on the other hand is
   a. an Apache module.  Some people run other web servers now or may 
      run other web servers in the future.
   b. not built into the Apache distribution.  It makes sysadmins nervous
      if they have to load strange code into their web server.
   b. works in a particular version of Apache.  sysadmins worry about
      what happens when they upgrade their Apache.  Will it be their
      job to deal with problems with mod_lisp and this version?

   Thus asking your sysadmin to proxy a portion of your company's url-space 
   over to your little app server is easy to get approved.  Asking your sysadmin
   to load a certain foreign module into the companies web server is going
   to require a lot of meetings.

2. Having the app server talk HTTP means 
   1. it can run standalone as well, perhaps to folks on your internal
      network.  Outsiders would have to go through mod_proxy but they
      would have an indentical experience to people internally.
   2. when you're debugging you can use a web browser. 
      You don't have Apache in the loop

   Security issues can be dealt with by having the app server look at
   the source address of the request.  It's a trival matter to 
   simply refuse to respond to requests outside of a range of IP addresses.

3. You can implement HTTP/1.0 (with keepalive) in the app server
   and mod_proxy will be happy.  You don't have to implement HTTP/1.1
   and chunking.
   HTTP/1.0 is very simple (probably just slightly more difficult to
   implement than the mod_lisp protocol).

-john foderaro
 franz inc

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