That was fast - awesome post. It sounds feasible, and I'm considering to use it. Still wondering, if it would be significantly slower than plain GWT-RPC? The sending limit of 2kB Client->Server will be enough for at least most of my queries - I must still evaluate, if it's enough for absolutely all of them (or if I can split the others easily).
One thing I must definitely make sure first, if this can be used together with all important frameworks I plan to use in the future (will e.g. gwt-log)... Thanks a lot for your answer! Chris On Jun 16, 10:53 pm, Sripathi Krishnan <sripathi.krish...@gmail.com> wrote: > Just did some digging in, and I *think* it is possible with some > restrictions. The restrictions being - > > - No support for request headers > - Reduced error handling. For example, a 404 cannot be detected > easily... > > The basic idea is to use DeRPC infrastructure because it already returns > JSON.. and try to override the RequestBuilder class so that the > communication channel is a <script> tag instead of a XHR. > > *Client Side changes* > > 1. Inject a custom RpcRequestBuilder via > RemoteServiceProxy.setRequestBuilder(). Lets call it JSONPRpcRequestBuilder > 2. In JSONPRpcRequestBuilder.doCreate(..) method, return a custom > RequestBuilder. Lets call it JSONPRequestBuilder. > 3. JSONPRequestBuilder class does all the heavy lifting. Override > *all*public methods. The serialized RPC data is available to this > class, so you > just need to URL encode it and construct a url > 4. Then just use built in JSONP classes to actually make the request > 5. You'd have to write an adaptor between RequestCallback (from > RequestBuilder) and AsyncCallback<T> (from JsonpRequestBuilder). > 6. Not sure how you'd typecast to the correct response object though. > Perhaps you may have to leverage the deRpc infrastructure - since it > already > consumes JSON objects in its response. > > *Server side changes* > This should be straighforward. The payload is present in a url parameter. > Use RPC class to decode the request, invoke the method and get the data. > Again, it would make sense to use deRpc as the starting point - since you > need to return JSON. > > There may be unforeseen problems, but I think it is possible to get it > working. And I guess there are advantages to it as well, you can truly share > you GWT services and no longer worry about cross domain issues. > > --Sri > > On 17 June 2010 01:21, Chris Lercher <cl_for_mail...@gmx.net> wrote: > > > > > Hi Sri, > > > I mean of course, that there would have to be a component (e.g. > > Servlet) on the server side, that re-translates the get request, and > > then calls the RemoteServlet (or something underlying), as if a usual > > GWT-RPC request had been issued. Se we would basically use JSONP as a > > tunnel. > > > [The defense against CSRF would have to be done using a separate > > technique, but let's forget about that for a moment.] > > > Chris > > > On Jun 16, 9:42 pm, Sripathi Krishnan <sripathi.krish...@gmail.com> > > wrote: > > > No, it won't. > > > > 1. GWT RPC exclusively uses POST. JSONP uses a <script> tag, which is > > > essentially a GET request. You can't make a POST request using a > > script tag. > > > 2. RPC adds custom http headers to the request (X-GWT-Permutation, or > > > something like that). You cannot setup custom http headers using a > > script > > > tag, or anyother html tag. > > > > Because of these two, RPC cannot be wrapped in a JSONP call. > > > > The restrictions on the URL length are not that prohibitive. GWT > > supported > > > browsers allow atleast 2KB, with the newer ones allowing more. That > > usually > > > is sufficient for most RPC calls. > > > > --Sri > > > -- > > You received this message because you are subscribed to the Google Groups > > "Google Web Toolkit" group. > > To post to this group, send email to google-web-tool...@googlegroups.com. > > To unsubscribe from this group, send email to > > google-web-toolkit+unsubscr...@googlegroups.com<google-web-toolkit%2Bunsubs > > cr...@googlegroups.com> > > . > > For more options, visit this group at > >http://groups.google.com/group/google-web-toolkit?hl=en. -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
