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
--~--~---------~--~----~------------~-------~--~----~
http://groups.google.com/group/Google-Web-Toolkit-Contributors
-~----------~----~----~----~------~----~------~--~---
