Re: Struts ActionForms and DWR/AJAX
I've just recently explored DWR for the first time, and I was quite impressed. However, my take was that of the authors of the page you cited -- there's really not much rationale that I can see for doing anything specifically with Struts and DWR together. Good practice for a Struts application would be for your Struts action classes to contain a minimum of business logic, and to primarily concern themselves with converting strings, the only kind of request parameters which can be submitted by HTTP, into whatever form is appropriate to your Struts-agnostic application layer. If you have this kind of organization, than DWR fits at the same layer as Struts, and given that it has full access to the Servlet-level execution context, it shouldn't need anything specific from Struts; your remoted object would do the same thing an action does, passing values into your business layer. The ability for DWR to remote beans defined with Spring makes this even easier, because you can make it very easy for the remoted object to reference these application-layer service beans. (You could always look them up in a ServletContext or something, but the Spring bean lookup is much more elegant.) The one concession to Struts that I made with my implementation (an "add to cart" feature) was to subclass the DWR ExecutionContext object to expose a Struts ActionContext object (actually, my own subclass of ActionContext) - this can easily be made any time a request, response, and servlet context are available, and it allows me to maintain a consistent guard against access to session and request scoped objects, rather than having to spread a bunch of references to String constant attribute names through out my code. As far as I can tell, DWR and Struts will co-exist peacefully together, but without much concern for each other. Is there a specific way in which you need DWR to use an ActionForm? If there is, that may be a sign of a place where you should re-organize the responsibilities of various classes in your application. Joe At 5:39 PM -0700 9/16/05, Greg Pelly wrote: I am thinking about migrating an application using Struts and ActionForms to use the DWR implementation of AJAX. I stood up a simple DWR sample and I'm realizing that it may not be possible to integrate DWR with ActionForms -- DWR makes requests through the "backdoor" (ie, XMLHttpRequest), rather than by submitting a form created by , so the Struts ActionForm does not get populated. In fact, request.getParameterNames() returns an 0-element enumeration, which makes me think it may not be possible at all. Does anyone have experience with ActionForms and AJAX? I did a quick Google search and found this article: http://getahead.ltd.uk/dwr/server/struts Any help would be appreciated. Greg - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] -- Joe Germuska [EMAIL PROTECTED] http://blog.germuska.com "Narrow minds are weapons made for mass destruction" -The Ex - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Struts ActionForms and DWR/AJAX
Michael Jouravlev wrote: On 9/17/05, Laurie Harper <[EMAIL PROTECTED]> wrote: Correct, Struts makes no distinction between GET and POST requests (other than transparently doing the extra request parsing for a POST). What do you mean by "extra request parsing for a POST"? Pulling parameters from request body instead of the parsing URL from the header? Exactly. About POST and GET: if I am not mistaken, user agent is required to ask for confirmation if result of POST is reloaded. On the other hand, I am not sure that this is the spec requirement, maybe not, need to verify. Yeah, but that's a browser behaviour and doesn't effect how the request is actually handled once the browser submits it. The sure difference is that redirecting from POST to POST requires confirmation, while redirecting from POST to GET - does not. Again, that's a browser behaviour thing rather than an issue with how the request gets processed. It's good to keep in mind, though :-) L. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Struts ActionForms and DWR/AJAX
On 9/17/05, Laurie Harper <[EMAIL PROTECTED]> wrote: > Frank W. Zammetti wrote: > > Further, I'm almost positive if you were to simply do a GET to an Action > > mapping with XMLHttpRequest, assuming the parameters you include in the > > query string match what would be POSTed from a form, it should work the > > same (never tried that... anyone else know differently?). > > Correct, Struts makes no distinction between GET and POST requests > (other than transparently doing the extra request parsing for a POST). What do you mean by "extra request parsing for a POST"? Pulling parameters from request body instead of the parsing URL from the header? About POST and GET: if I am not mistaken, user agent is required to ask for confirmation if result of POST is reloaded. On the other hand, I am not sure that this is the spec requirement, maybe not, need to verify. The sure difference is that redirecting from POST to POST requires confirmation, while redirecting from POST to GET - does not. Michael. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Struts ActionForms and DWR/AJAX
Frank W. Zammetti wrote: Further, I'm almost positive if you were to simply do a GET to an Action mapping with XMLHttpRequest, assuming the parameters you include in the query string match what would be POSTed from a form, it should work the same (never tried that... anyone else know differently?). Correct, Struts makes no distinction between GET and POST requests (other than transparently doing the extra request parsing for a POST). L. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Struts ActionForms and DWR/AJAX
Thanks for the props Martin! :) Greg... one common misconception about AJAX is that it needs to involve XML. It doesn't (ok, it probably shouldn't be called AJAX in that case, AJA? perhaps...) Note that there is nothing special about a form being submitted to a Struts Action... The Struts HTML taglib hides some of the details from you, but underneath it's a perfectly ordinary HTML form that results in a perfectly ordinary HTTP POST request. On the server, the parameters are retrieved and the ActionForm populated, if applicable, and your Action called. XMLHttpRequest does exactly the same thing when you get right down to it: it's just an ordinary HTTP request too. The pertinent point is that you can specify the method to use (GET or POST) for the object. Take a look here: http://www.devx.com/DevX/Tip/17500 This is a quick tip that shows how to POST with XMLHttpRequest. If you were to use this example and target an Action mapping, you should find that the ActionForm does get populated, and Struts works exactly as it always does. Well, except for what's returned of course... there has to be some client-side script that knows how to interpret whatever the Action (or JSP) returns. But as far as Struts is concerned, it's business as usual. Further, I'm almost positive if you were to simply do a GET to an Action mapping with XMLHttpRequest, assuming the parameters you include in the query string match what would be POSTed from a form, it should work the same (never tried that... anyone else know differently?). But regardless of that... I have no experience with DWR, so I can't give you specifics... But, assuming you can make it do as the above link demonstrates, then as far as Struts is concerned, an AJAX request is no different from a "normal" request. You can have your auto-population of ActionForm and DWR too. Alternatively, you might consider AjaxTags in Java Web Parts: http://javawebparts.sourceforge.net/javadocs/index.html It's definitely not the same as DWR and might not fit your requirements, but you can't expect me to not plug my own creation, can you?!? :) Frank Martin Gainty wrote: Greg- check out Frank Zammetti's tutorial for Asynchronous JavaScript with XML http://www.omnytex.com/articles/xhrstruts/ A most excellent primer.. HTH, Martin - Original Message - From: "Greg Pelly" <[EMAIL PROTECTED]> To: "Struts Users Mailing List" Sent: Friday, September 16, 2005 8:39 PM Subject: Struts ActionForms and DWR/AJAX I am thinking about migrating an application using Struts and ActionForms to use the DWR implementation of AJAX. I stood up a simple DWR sample and I'm realizing that it may not be possible to integrate DWR with ActionForms -- DWR makes requests through the "backdoor" (ie, XMLHttpRequest), rather than by submitting a form created by , so the Struts ActionForm does not get populated. In fact, request.getParameterNames() returns an 0-element enumeration, which makes me think it may not be possible at all. Does anyone have experience with ActionForms and AJAX? I did a quick Google search and found this article: http://getahead.ltd.uk/dwr/server/struts Any help would be appreciated. Greg - 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] -- Frank W. Zammetti Founder and Chief Software Architect Omnytex Technologies http://www.omnytex.com - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Struts ActionForms and DWR/AJAX
Greg- check out Frank Zammetti's tutorial for Asynchronous JavaScript with XML http://www.omnytex.com/articles/xhrstruts/ A most excellent primer.. HTH, Martin - Original Message - From: "Greg Pelly" <[EMAIL PROTECTED]> To: "Struts Users Mailing List" Sent: Friday, September 16, 2005 8:39 PM Subject: Struts ActionForms and DWR/AJAX I am thinking about migrating an application using Struts and ActionForms to use the DWR implementation of AJAX. I stood up a simple DWR sample and I'm realizing that it may not be possible to integrate DWR with ActionForms -- DWR makes requests through the "backdoor" (ie, XMLHttpRequest), rather than by submitting a form created by , so the Struts ActionForm does not get populated. In fact, request.getParameterNames() returns an 0-element enumeration, which makes me think it may not be possible at all. Does anyone have experience with ActionForms and AJAX? I did a quick Google search and found this article: http://getahead.ltd.uk/dwr/server/struts Any help would be appreciated. Greg - 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]
Struts ActionForms and DWR/AJAX
I am thinking about migrating an application using Struts and ActionForms to use the DWR implementation of AJAX. I stood up a simple DWR sample and I'm realizing that it may not be possible to integrate DWR with ActionForms -- DWR makes requests through the "backdoor" (ie, XMLHttpRequest), rather than by submitting a form created by , so the Struts ActionForm does not get populated. In fact, request.getParameterNames() returns an 0-element enumeration, which makes me think it may not be possible at all. Does anyone have experience with ActionForms and AJAX? I did a quick Google search and found this article: http://getahead.ltd.uk/dwr/server/struts Any help would be appreciated. Greg - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
