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From Wolle <wo...@dorf.RWTH-Aachen.DE>
Subject Re: ajp12, ajp13, mod_webapp, and http protocols
Date Sat, 05 May 2001 15:04:37 GMT
in the documentation of the ajp13 Protocol is something written, that ajp13
the isSecure Methode on Servlets for SSL, but I have tested it with ajp12,
and the isSecure Methode works,too.


kevin seguin wrote:

> i'm not the expert on these things, but i'll try to answer your
> questions as best i can.  i'm sure if i say something that is blatantly
> wrong, i will be corrected ;)  the information here is pretty much what
> i've figured out for myself using tomcat over the last year or so...
> >
> > I am using mod_jk right now and I am wondering why
> > ajp12, ajp13, and mod_webapp protocols were originally
> > introduced.
> >
> i believe the original reason why mod_jserv and ajp were introduced was
> for connecting the apache web server to the old JServ servlet
> container.  when tomcat showed up, mod_jserv was used for it too.  i
> think mod_jk, which added support for more web servers (i.e.
> iis/netscape) was then introduced as a replacement for mod_jserv.  ajp13
> is an evolution (revolution??) of ajp12.  it's faster.
> > http protocol can be passed through most firewalls
> > whereas ajp12 and ajp13 can not.  In some real world
> > websites, there are lots of cases that there is an
> > inner firewall between Web server and web container.
> >
> > http protocol version 1.1's "keepalive" could be used
> > for consistant connections.
> >
> > Almost all the available web containers have at least
> > one http listener while some of them do not support
> > ajpxx protocols, such as the current Orion.
> >
> i'm not sure what this has to do with mod_jk/ajp...
> > I implemented an http worker in mod_jk by myself and
> > it works fine for me.
> >
> > So, my question is, what are the advantages of ajp12,
> > ajp13, and mod_webapp protocols versus http protocol?
> >
> i think you may have missed the point of ajp.  mod_jk and ajp are used
> to connect web servers to tomcat.  essentially what they do is intercept
> http requests in a web server and forward them to tomcat to be handled
> there.  i'm not even sure if http could have been used to do this... it
> would have been weird, i think, because you have to forward all
> information about the request (headers, posted data, etc.) and if you
> made another http request from the web server to tomcat, you'd have a
> whole new set of headers and you'd have to have something to decode that
> request on the tomcat side and ... well, i'm rambling.  i think ajp is
> just a cleaner and more efficient approach.  also, i don't even know if
> the original JServ handled http...
> anyway, as i said, i'm not the expert on this subject, so hopefully
> someone with a better history with mod_jserv/mod_jk/ajp will correct any
> lies i may have told :)
> also, you should take a look at the documentation, particularly the
> mod_jk-howto and the ajp13 docs that come with tomcat 3.x (maybe only
> 3.3...).



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