Re: [Demexp-dev] On web client, XML and ONC RPC and their integration with demexp

[David MENTRE]

Hello Augustin,

Augustin <address@hidden> writes:

> The Drupal API is well documented:
> http://api.drupal.org/apis/HEAD/xmlrp

Thank you for the pointers.

> Also how difficult would it be to set up a server for development?

You mean, a demexp server. Quite easy with a static binary or with
Thomas's Ubuntu and Debian packages, a nightmare from sources.

I can easily provide a statically linked version if needed.

> Most of the posts I found discussing the relative merits of the two standards 
> date back to the last 1990s. It seems that this century, everybody accepts 
> XML RPC as the web standard. 

This is not because everybody does the same thing that everybody is
right. :-)

> So, why not use XML RPC only, and announce that once the official server is 
> upgraded, it will stop replying to ONC RP Calls?

Because:

 1. the current code is debugged and tested, with non regression
    tests. Starting from scratch would be a big overhead;

 2. for all the reasons I have given on XML RPC, most notably the lack
    of short description of message format.

> I guess you will not like this solution, for reasons you have already 
> mentioned, but I thought it was an idea worth mentioning.

Good attempt, but no success. ;-)

> Remember that XML RPC is the de-facto standard nowadays. 
> We want to make future development easier.

That's why I'm looking at way to have an XML RPC interface.

> If I understand well, all of this would happen on the server side.
> All of this would be completely transparent to me, who will code the client, 
> wouldn't it?

Yes.

> Your idea sounds very similar to this one I found:
> http://www.thescripts.com/forum/thread86837.html
> ""I've an old ONC XDR RPC server. I want to write clients in XML RPC.
>  Thus, it is my intention to write a XML RPC <-> XDR RPC converter
>  (open source, to share it in some public repository).
>  In other words, my program will be a XML RPC server and XDR RPC
>  client. Queries received in XML RPC server side will be forwaded and
>  sent as request in XDR RPC side.""
>
> The problem is that this guy never got a reply (even though this very same 
> post had been posted to different forums), and he never left a contact email 
> or web site.
> There just doesn't seem to be much interest for such a proxy either.

The main thing is that you can't make a generic proxy because, as I said
on demexp-fr@, the ONC RPC message format is implicit (no typing
information is included in the message itself). However, it is perfectly
possible to make a generic /generator/ of XML RPC/ONC RPC proxy.


> Again, you are the one who will do most/all of the coding for this, so you 
> decide. Tell me if you think I can help in any way, and then tell me the 
> exact protocol to contact the server from a php script.

>From what I have read, it would be standard XML RPC, with a direct
translation of ONC RPC format to XML RPC. I haven't work out yet the
details. 

> But please, do think about the long term consequences of the technical choice 
> you are about to make. 

Oh yes, I do know that. Taking a decision is the hard part, programming
the easy part. :-)

> If I could write this script today, then I could write the whole drupal 
> demexp 
> module within a few weeks only. The implications are important. You have 
> ruled out 2007 as an opportunity to publicize your (our) project, but I 
> haven't. By the end of this year, we could have a debugged, fairly ironed out 
> web client that masses of people could use to register and participate in the 
> Democratic Experience. demexp.org could become one of the most popular web 
> site during the 2007 electoral campaign (I believe this and it is because I 
> had this intuition that I contacted you in the first place, and offered to 
> code the client).

I would not give my head for the 2007 deadline but it would be worth a
good attempt.

> If instead of trying to manage at the same time the hard client and the web 
> client, worry at the same time about the ONC RPC server and the XML RPC 
> proxy, if instead of that you could concentrate on one task (server <-> XML 
> RPC <-> client), how much quicker do you think you could be?

Switching completely from ONC RPC to XML RPC would take me too long (and
I'm not motivated at all for it).

> Unfortunately, I am feeling a bit helpless at the moment. Just tell me if I 
> can help at all.

No particular thing. If you want to plan some code, think at using plain
XML RPC, with message structure directly inspired from XDR description.

> Until then, I am only waiting for you (and Thomas) to make you final 
> technical/tactical decision.

Currently, I'm in favor of doing a XML RPC <-> ONC RPC proxy for demexp,
probably in Pythoon (which as required API to make an XML RPC server).

Best wishes,
d.
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