Converting XHR from onLoad to onReadyStateChange

Converting XHR from onLoad to onReadyStateChange

Thought that onLoad was sufficient, but it's causing issues for loading files from file:// URIs (from a Chrome extension).

BUG=8401
Committed: https://code.google.com/p/dart/source/detail?r=18233

[blois, 2013-02-07 20:53:10]

Going back on onLoad, the problem was that file:// URIs have status of 0 (since
they don't use the HTTP protocol).

[Emily Fortuna, 2013-02-07 20:53:44]

https://codereview.chromium.org/12224055/diff/1/tools/dom/templates/html/impl...
File tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate (right):

https://codereview.chromium.org/12224055/diff/1/tools/dom/templates/html/impl...
tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate:100: xhr.status
== 304 ) {
This doesn't fix the problem described in dartbug.com/8401. What you should do
instead is run this branch if the status is also 0 (you can check if the request
is for a file URL specifically). The problem is status will be 0 for a local
file, regardless of whether or not it is actually "found"! So, completing as
opposed to completeError in that one case could be slightly misleading. That's
why I didn't have an actual error condition in the previous version of this
code. I think the flow described though is probably the least strange for most
cases.

[Emily Fortuna, 2013-02-07 20:55:50]

lgtm, once the explanatory comment is also added.

https://codereview.chromium.org/12224055/diff/3001/tools/dom/templates/html/i...
File tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate (right):

https://codereview.chromium.org/12224055/diff/3001/tools/dom/templates/html/i...
tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate:100: xhr.status
== 0 || xhr.status == 304) {
note -- please add in the comments of this method that if you are doing an xhr
request for a file:// URI, completeError WILL NEVER FIRE -- because the status
will be 0, regardless of whether the file is found or not.

[Siggi Cherem (dart-lang), 2013-02-07 21:03:30]

https://codereview.chromium.org/12224055/diff/3001/tools/dom/templates/html/i...
File tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate (right):

https://codereview.chromium.org/12224055/diff/3001/tools/dom/templates/html/i...
tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate:103:
completer.completeError(e);
not for this CL, but we should also consider whether the error should be 'e'
should be the event or a special error object (maybe that points to both xhr and
the event?).

When I got the error object I wasn't sure how to use it. Turns out I really
wanted to use xhr to inspect what was happening.

[blois, 2013-02-07 21:09:42]

On 2013/02/07 21:03:30, Siggi Cherem (dart-lang) wrote:
>
https://codereview.chromium.org/12224055/diff/3001/tools/dom/templates/html/i...
> File tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate (right):
> 
>
https://codereview.chromium.org/12224055/diff/3001/tools/dom/templates/html/i...
> tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate:103:
> completer.completeError(e);
> not for this CL, but we should also consider whether the error should be 'e'
> should be the event or a special error object (maybe that points to both xhr
and
> the event?).
> 
> When I got the error object I wasn't sure how to use it. Turns out I really
> wanted to use xhr to inspect what was happening.

The target of the event is the XHR

[Siggi Cherem (dart-lang), 2013-02-07 21:50:54]

On 2013/02/07 21:09:42, blois wrote:
> On 2013/02/07 21:03:30, Siggi Cherem (dart-lang) wrote:
> >
>
https://codereview.chromium.org/12224055/diff/3001/tools/dom/templates/html/i...
> > File tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate (right):
> > 
> >
>
https://codereview.chromium.org/12224055/diff/3001/tools/dom/templates/html/i...
> > tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate:103:
> > completer.completeError(e);
> > not for this CL, but we should also consider whether the error should be 'e'
> > should be the event or a special error object (maybe that points to both xhr
> and
> > the event?).
> > 
> > When I got the error object I wasn't sure how to use it. Turns out I really
> > wanted to use xhr to inspect what was happening.
> 
> The target of the event is the XHR

Ah! good to know. THanks =)