I think at some point to make this really worth anything I'll have to break my "transparency rule" to some extent. I do like the idea of generating the output with a JSP because it's just so easy! A little bit of background... I actually implemented this same thing in a custom framework we were previously using in-house. In that application I actually do write out the output in servlets, there is never a forward to a JSP or anything else typically in the "view" layer. This works just fine, but when I started doing it in Struts it ocurred to me that I could really simplify things by not taking that approach and instead let the actual XML generation be done in a JSP. That also removed the one change that was required under the old framework: you did have to add two function calls to the controller servlets that were exposed as services. Not a big change, but I wanted to avoid code changes entirely here.
At this point my belief is that probably the best way to handle this is to have an element added to the Action mappings in Struts-Config.xml that specifies the target JSP for a Web Service request. The default woudl be the "generic" template I put together, although a bit more flexible as time goes on. But, the point is that you could then define an XML template in essence for every Action you wanted to expose as a service. That would allow for things I probably can't do automatically. I'd also write a taglib to make life easier (although I might not have to... the current Struts taglibs might be more than sufficient on their own).
That would of course require a change to the DTD for Struts-Config.xml, so in the mean time what I think I'm going to do is add an optional config file thatwould be parsed via a plug-in at app startup that would contain these extra mappings. Fairly trivial exercise, and it leaves it completely optional, no changes to Struts required.
Also, I realized on the drive in that there's no need to put the parameters as a query string as I'm doing... I can just put the parsed parameters directly into the request object as an attribute. Since only the second pass of a Web Service request would know or care about that object, it will basically just remove some code and simplify things a bit.
I'm hoping to get these thnigs done today and release a .02 package before I leave work today (it's nice when your development server is down and you can't do any real work until the techs rebuild it!)... I also hope to remove the required actionMappingPath element in the XML request... I haven't found a way to get at the requested pat information in RequestProcessor yet, but it seems like something that should be available at that point, so I probably just have to do some digging.
What is AOP by the way? Millions of acronyms out there, I know thousands of them, but not that one :)
Thanks very much for the feedback!
Frank
From: "Marco Mistroni" <[EMAIL PROTECTED]> Reply-To: "Struts Users Mailing List" <[EMAIL PROTECTED]> To: "'Struts Users Mailing List'" <[EMAIL PROTECTED]> Subject: RE: Strus Web Service Enablement Date: Thu, 3 Jun 2004 14:25:47 +0100
Hi, Well, main issue here is that if you want everything to be transparent To the user (including the forward) then whole stuff has to be done so that Something 'intercepts' the response when XML is contained in it (if I can explain myself correctly)
In other way, to do same steps that you have already done with RequestProcessor Not being familiar with struts internal (other than action &actionform) I can't really say where to modify things...
Another way would be, for each CustomAction written, write an CustomActionXml that extends CustomAction. This CustomActionXml will Be invoked whenever the path is for CustomAction AND the request is in XML. The logic will be done in the original CustomAction, difference being in the fact that CustomActionXml instead of redirecting to the 'original' forward of CustomAction, writes the response to outputWriter But this gets cumbersome..
I would go for doing with response exactly what u r doing with request.. Though right now I have no clue on how to do it...maybe u or some struts expert which knows inner logic of struts knows?
Will AOP help in any way here?
Regards marco
Extends
-----Original Message----- From: Frank Zammetti [mailto:[EMAIL PROTECTED] Sent: 03 June 2004 13:33 To: [EMAIL PROTECTED] Subject: RE: Strus Web Service Enablement
I have to be honest and say I've never used a filter except for one situation to do security on the input side, a very basic application. How would you envision it being used for the output?
>From: "Marco Mistroni" <[EMAIL PROTECTED]> >Reply-To: "Struts Users Mailing List" <[EMAIL PROTECTED]> >To: "'Struts Users Mailing List'" <[EMAIL PROTECTED]> >Subject: RE: Strus Web Service Enablement >Date: Thu, 3 Jun 2004 10:15:43 +0100 > >Hi, > My 2 cents.... I think that is a great idea!!!! > >Do u think that using a filter for the response will help? > >Last year I did something similar (wrote a Struts-based webapp >That I was talking to using J2ME and KSOAP..but all I was able >To do was to extend existing action and dump the generated XML >Into the response.getWriter().write()... I was using axis btw for >XML stuff on the serverside) > >Regards > marco > > > >-----Original Message----- >From: Frank Zammetti [mailto:[EMAIL PROTECTED] >Sent: 02 June 2004 21:29 >To: [EMAIL PROTECTED] >Subject: RFC: Strus Web Service Enablement > >Hello all... I wanted to post this here and get any comments that people >had >so I could decide where to go with it... > >For the past two days I've been working on a mechanism that would allow >you >to expose existing Struts-based business logic as Web Services without >changing any existing code. What I offer here is a first approximation >of >that idea. > >If you might be interested in this, you can download the first iteration >of >the project at http://www.omnytex.com/wst.zip > >This archive is a sample webapp in exploded format. Just unzip it to >your >webapps directory of your chosen app server and you should be good to >go. >I've only tried it on Tomcat however, so anything else is unknown. > >In a nutshell, what I've done is written a custom subclass of >RequestProcessor. This version will recognize a SOAP-based Web Service >request, "unroll" the request, and hand it off to a specified Action. >As >far as the Action is concerned, it looks just like a regular HTTP form >submission, so it processes same as before. Note that the request is >forwarded back through ActionServlet, so anything you do should still >work. >The RequestProcessor then overrides the destination ActionForward that >the >Action returns, and instead sends it to a special JSP, which renders the > >response XML. The response type is set properly, and the generated XML >is >returned. The XML it generates simply dumps all members of the >ActionForm, >so it's not very smart right now, but as I said, this is a first >approximation of the idea. > >So, in the end, you should be able to expose any existing Actions as Web > >Services without changing them. Everything you need is included, except >for >a JDK, but I assume you have that already (!), including a dirt-simple >test >client. It's not a true SOAP client, but it gets the job done. > >Once you unzip the archive, I suggest reading the readme.txt file in the > >/source directory. This goes into a bit more detail on everything, as >well >as explaining how to use this in your own application. I should also >note >that this RequestProcessor is transparent to non-Web Service requests, >i.e., >you can use it in your existing apps without changing anything whether >you >expose anything as a service or not. > >I thank anyone in advance that checks this out. Please send me any >comments >or suggestions you may have either to [EMAIL PROTECTED] or just post > >them here. > >My hope is that given some time to refine this it will be tight enough >and >useful enough that maybe I can present it to the developer list for >possible >inclusion in the base Struts distro. That's of course a ways off, if it > >ever reaches that point, but it's a start I think. > >Good day to all! > >Frank > >_________________________________________________________________ >Looking to buy a house? Get informed with the Home Buying Guide from MSN > >House & Home. http://coldwellbanker.msn.com/ > > >--------------------------------------------------------------------- >To unsubscribe, e-mail: [EMAIL PROTECTED] >For additional commands, e-mail: [EMAIL PROTECTED] > > >--------------------------------------------------------------------- >To unsubscribe, e-mail: [EMAIL PROTECTED] >For additional commands, e-mail: [EMAIL PROTECTED] >
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