URIS

  http://codeforpeople.com/lib/ruby/acgi/


SYNOPSIS

  as·sid·u·ous (adj.)

    1. constant in application or attention; diligent: an assiduous worker who
    strove for perfection.

    2. unceasing; persistent: assiduous research. 

  acgi : assiduous or ara's cgi (emphasis on the 'ass' in assiduous) a drop-in
  replacement for ruby's built-in cgi that provides copious features such as

    - no apache modules
    - persistence
    - speed
    - simplicity
    - familiarity
    - no apache modules
    - browser neutrality
    - could easily be made platform independent
    - no apache modules
    - no special webserver setup or system privledges required
    - ability to install to a webserver via ftp
    - no apache modules
    - session affinity, all request handled by one process
    - automatic reload if code changes
    - ability to run script simulaneously as acgi and cgi for debuggging
    - ability to easily start/stop/restart/check-on running server
    - 178 lines of ruby code (and one c program)
    - no apache modules


PERFORMANCE

  case one, a simple cgi that just dumps the environment:        

  with acgi:

    [ahoward@localhost acgi-0.1.0]$ ab -n100 -c4 http://localhost/acgi/acgi-0.1.0/ | grep 'Requests per second'
    Requests per second:    74.93 [#/sec] (mean)

  without:

    [ahoward@localhost acgi-0.1.0]$ ab -n100 -c4 http://localhost/acgi/acgi-0.1.0/server.cgi | grep 'Requests per second'
    Requests per second:    18.76 [#/sec] (mean)


  a more realistic cgi that uses sessions and sleeps for 1 second to mimic
  connecting to a database:

  with acgi:

    [ahoward@localhost acgi-0.1.0]$ ab -n100 -c4 http://localhost/acgi/acgi-0.1.0/ | grep 'Requests per second'
    Requests per second:    24.20 [#/sec] (mean)

  without:

    [ahoward@localhost acgi-0.1.0]$ ab -n100 -c4 http://localhost/acgi/acgi-0.1.0/server.cgi | grep 'Requests per second'
    Requests per second:    3.63 [#/sec] (mean)


ARCHITECHTURE

  the design of acgi is similar to that of fastcgi (http://www.fastcgi.com) but
  requires no external modules, configuration of apache, etc.

  a acgi application consists of a cgi server backend which loops, handling all
  incoming requests; the requests are delegated to this backend server via a
  simple, fast to start up, 'index.cgi' program written in c.  communication
  between 'index.cgi' and it's backend server is via named pipes (fifos):


                        -------------
                        | index.cgi |          <- transient compiled c code
                        -------------             
                        |	|   |
                        | fifos for stderr, stdout, stdin, env
                        |	|   |
                       /	|    \
                ------------------------------
                |                            | 
                |         cgi server         | <- persistent looping ruby code
                |                            | 
                ------------------------------

  note that the architechture is similar in spirit to fastcgi - it provides
  speed by avoiding startup overhead and redundant work like database connection
  setup.  in this case, contrasted with fastcgi, the whole thing takes place
  outside of the webserver in the applica