Multiple "pages" in GWT with human friendly URLs
- by Andreas Borglin
Hi.
I'm playing with a GWT/GAE project which will have three different "pages", although it is not really pages in a GWT sense. The top views (one for each page) will have completely different layouts, but some of the widgets will be shared.
One of the pages is the main page which is loaded by the default url (http://www.site.com), but the other two needs additional URL information to differentiate the page type. They also need a name parameter, (like http://www.site.com/project/project-name. There are at least two solutions to this that I'm aware of.
Use GWT history mechanism and let page type and parameters (such as project name) be part of the history token.
Use servlets with url-mapping patterns (like /project/*)
The first choice might seem obvious at first, but it has several drawbacks. First, a user should be able to easily remember and type URL directly to a project. It is hard to produce a human friendly URL with history tokens. Second, I'm using gwt-presenter and this approach would mean that we need to support subplaces in one token, which I'd rather avoid. Third, a user will typically stay at one page, so it makes more sense that the page information is part of the "static" URL.
Using servlets solves all these problems, but also creates other ones.
So my first questions is, what is the best solution here?
If I would go for the servlet solution, new questions pop up.
It might make sense to split the GWT app into three separate modules, each with an entry point. Each servlet that is mapped to a certain page would then simply forward the request to the GWT module that handles that page. Since a user typically stays at one page, the browser only needs to load the js for that page. Based on what I've read, this solution is not really recommended.
I could also stick with one module, but then GWT needs to find out which page it should display. It could either query the server or parse the URL itself.
If I stick with one GWT module, I need to keep the page information stored on server side. Naturally I thought about sessions, but I'm not sure if its a good idea to mix page information with user data. A session usually lives between user login and logout, but in this case it would need different behavior. Would it be bad practise to handle this via sessions?
The one GWT module + servlet solution also leads to another problem. If a user goes from a project page to the main page, how will GWT know that this has happened? The app will not be reloaded, so it will be treated as a simple state change. It seems rather ineffecient to have to check page info for every state change.
Anyone care to guide me out of the foggy darkness that surrounds me? :-)
