SGTM.
On Thu, Jan 22, 2009 at 12:14 PM, Lex Spoon <sp...@google.com> wrote:
>
> I'd like runAsync to use XHR for the iframe linker, so that GWT
> applications can get timely notification if an async code download
> fails for any reason.
>
> I've outlined all the code changes, but there is a remaining question
> about how the runAsync support should access XHR. Ten minutes of
> reading through RequestBuilder and related classes is very convincing
> that that's the code to use. It's a classic case where different
> browsers do a variety of weird and quirky things, and there are
> solutions to all the known quirks already implemented in those
> classes.
>
> The problem is that GWT.runAsync is in Core, RequestBuilder requires
> UserAgent, and Core is not supposed to require UserAgent.
>
> To solve this problem, how about we make a generic RequestBuilder that
> can be used in Core, and then add deferred bindings for the common
> case that UserAgent is included? It would be analogous to what we do
> for StringBuffer.
>
> After looking at the implementation, I believe the only thing
> sensitive to the user agent is the method doCreateXmlHTTPRequest().
> The rest of the code is shared. If that's the case, wouldn't it be
> possible to define a generic doCreateXmlHTTPRequest that handles all
> browsers? It would look like the current IE implementation except
> with an additional catch block:
>
>
> @Override
> protected native JavaScriptObject doCreateXmlHTTPRequest() /*-{
> if ($wnd.XMLHttpRequest) {
> return new XMLHttpRequest();
> } else {
> try {
> return new ActiveXObject('MSXML2.XMLHTTP.3.0');
> } catch (e) {
> try {
> return new ActiveXObject("Microsoft.XMLHTTP");
> } catch (e) {
> // new catch block
> return new XMLHttpRequest();
> }
> }
> }
> }-*/;
>
>
> Assuming the above implementation is reliable, HTTPRequestImpl could
> use it as the implementation in the base class. We could add a new
> class HTTPRequestImplNonIE6 that has the simple "return new
> XMLHttpRequest" that works on all non-IE browsers.
>
> The modules would be changed as follows:
>
> Core would inherit HTTP, and thus get a functioning but suboptimal
> RequestBuilder
>
> HTTPRequest would change its default binding of HTTPRequestImpl to
> HTTPRequestImplNonIE6
>
>
>
> Before I experiment further, does anyone spot anything to worry about?
>
>
> Lex
>
> >
>
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