Grails, spring-ws, SOAP & HTTP request's content type

If you ever have to use Grails to process a fucked up SOAP request with a content type of application/x-www-form-urlencoded then this post is for you.

p.s. eventually we will stop processing that kind of requests but for now we need it to work so client has time to fix their shit up

Problem with application/x-www-form-urlencoded requests & spring-ws' message factory is that it does not like requests with that content type. Rightly so!

The message factory content type issue is obvious since the exception that it throws at you is pretty self-explanatory. The work-around is pretty easy, define your own messageFactory spring bean that is more lenient on the content type.

But after the content type is sorted you would face the second problem "Premature end of file". It took me a while to figure out what is happening. In retrospect it is actually quite logical. The end of file is referring to the request's input stream which has been consumed by Grails filters before it gets to the message factory. The following filters are responsible for parsing the request and routing, luckily they are also subclasses of OncePerRequestFilter which means you can easily bypass them to avoid input stream been consumed.

1. grailsWebRequest
2. urlMapping
3. hiddenHttpMethod

 

How to use Groovy categories in gsp's

You use Groovy categories in a canonical way in gsp's. i.e. by surrounding all your gsp code inside a call to

<% use(YourCategoryClass) { %>

<% } %>

But it gets troublesome quite soon, especially if the main gsp renders other partial templates.

Luckily there is a way to hook into the view rendering workflow. The trick is to provide your own implementation of View that invoke the call to use categories around the view.render method. To do that you also need to override the default jspViewResolver spring bean with your own implementation of ViewResolver which uses your own implementation of View. Lastly if you need dynamically decide what categories classes to use then you can pass it in the model attribute inside your controller.

The result will look something like this.

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class MyGrailsViewResolver extends GrailsViewResolver {     @Override     protected View loadView(String viewName, Locale locale) {         new MyView(super.loadView(viewName, locale))     }     static class MyView implements View {         def View view         MyView(View view) {             this.view = view         }         String getContentType() {             view.getContentType()         }         void render(Map<String, ?> model, HttpServletRequest request, HttpServletResponse response) {             if (model.categories) {                 use(model.remove('categories')) {                     view.render model, request, response                 }             } else {                 view.render model, request, response             }         }     } }