httpd module vs inets {packet,http}

Ryan Rawson <>
Wed Mar 8 22:13:15 CET 2006


Thanks for the advice guys.

My understanding of REST is basically a rejection of SOAP -
essentially instead of saying "use POST and send this XML request
document and get a reply", instead, embed the request in the URI/URL. 
Use what we already know works - GET for read-requests and POST for
write-requests.

-ryan

On 3/8/06, Jon Hancock <> wrote:
> My understanding is that REST is all about returning XML documents.
> So a gross overview of the REST transaction life-cycle is:
>         1 - fetch incoming requests (I think REST requests come wrapped in
> an HTTP format?)
>         2 - decode the request's URI and parameters
>         3 -  statically or dynamically construct the resource to return
>         4 - return the resource as an XML doc
>
> Yaws will be a champ at this sort of thing.
> The HowTo you reference is enlightening and well written.  The HowTo
> shows how to write your own socket server.    You would only want to
> do this for something very specialized.  For example, if you wanted
> to build a new server to handle some custom protocol you've written
> you would start with this HowTo structure and build from there.  I am
> building an app that has just this requirement and I found the HowTo
> to be a solid starting point.
> But for your needs, go with Yaws.
>
> On Mar 8, 2006, at 6:24 PM, Ryan Rawson wrote:
>
> > Would you mind elaborating a bit for me?
> >
> > Basically my application is going to automatically discover its fellow
> > node hosts via LDAP (we have a mechanism already), use mnesia to
> > maintain state across them, and each machine is going to answer HTTP
> > service queries.  That is my current design - one major advantage is
> > mnesia is a great cross-node database, great for high read/low write
> > services that need to be able to answer questions quickly but don't do
> > nearly as many writes.  This particular feature of my app made me
> > think Erlang would be well suited.
> >
> > -ryan
> >
> >
> > On 3/8/06, Sean Hinde <> wrote:
> >> That is interesting feedback on the tutorial, thanks.
> >>
> >> If I can find time to wrestle again with the sometimes flaky update
> >> mechanism on the Trapexit HOWTO pages I will update the tutorial to
> >> point out more clearly where the API to user code appears, as well as
> >> checkin a couple of bugfixes from folks who have studied it deeply
> >> and posted on the list.
> >>
> >> FWIW I would recommend Yaws most highly for new applications. It is
> >> not nearly as heavyweight as it first appears, and is very nice for
> >> writing this sort of application.
> >>
> >> Sean
> >>
> >> On 8 Mar 2006, at 08:11, Ryan Rawson wrote:
> >>
> >>> I didn't like the howto - it seemed like my code would be littered
> >>> with http protocol droppings, even though the actual framing is
> >>> taken
> >>> care of by the http packet mode.
> >>>
> >>> I think for me, yaws seems like this whole big thing, and kind of
> >>> bothers me - enough to look at alternatives first.
> >>>
> >>> Thanks for the mod_esi pointer.
> >>>
> >>> -ryan
> >>>
> >>> On 3/8/06, Matthias Lang <> wrote:
> >>>>
> >>>> A "REST" web service seems to be some sort philosophy for how to
> >>>> design a service. For the purpose of "how do I do this in
> >>>> Erlang", I
> >>>> think it just boils down to "how do I serve dynamically
> >>>> generated web
> >>>> pages". If it's not, then my answer probably misses the point.
> >>>>
> >>>> So: if you just want to serve dynamic web pages, you can choose
> >>>> between two ready-made web servers: OTP's httpd and YAWS. Both web
> >>>> servers are used in the real world. They have different peformance
> >>>> tradeoffs and different approaches to interfacing with 'your'
> >>>> application. YAWS seems to be more popular for new applications. If
> >>>> you can't make up your mind about which one to use, flip a coin.
> >>>>
> >>>> The OTP httpd interface you probably want to use is 'mod_esi':
> >>>>
> >>>>   http://www.erlang.org/doc/doc-5.4.12/lib/inets-4.6.2/doc/html/
> >>>> mod_esi.html
> >>>>
> >>>> Writing code to use it is straightforward, the hard part is all the
> >>>> fudging around with httpd.conf.
> >>>>
> >>>> If, on the other hand, you want to write your own web server 'from
> >>>> scratch', then the undocumented http mode of the packet driver is
> >>>> useful. That's what the 'howto' you found is about.
> >>>>
> >>>> Matthias
> >>>>
> >>>> --------------------
> >>>>
> >>>> Ryan Rawson writes:
> >>>>> Hi all,
> >>>>>
> >>>>> I read the 'fast httpd' howto from trapexit.org, and I also
> >>>>> looked at
> >>>>> the httpd module in OTS.  I'm a little confused - it seems to me
> >>>>> that
> >>>>> the httpd howto doesn't use the httpd module, it uses a
> >>>>> undocumented
> >>>>> feature of the packet driver (which may in turn internally use the
> >>>>> httpd module).  While the httpd documentation seems to describe
> >>>>> callbacks but its kind of thinly documented.  Not the end of the
> >>>>> world, but I'm confused - what is the recommended thing to do
> >>>>> here?
> >>>>> What do other people do?  Say for example, creating a REST "web
> >>>>> service" ?
> >>>>>
> >>>>> Thanks in advance for any tips and hints.
> >>>>> -ryan
> >>>>
> >>
> >>
>
>



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