xhrGet: ioArgs are not passed on to dojo.Deferred.then

[Simon Speich]

If I use the returned deferred instead of the load/error callbacks in a xhrGet(), the ioArgs are not passed to the dojo.Deferred.then(), e.g.:

var dfd = dojo.xhrGet({
	...
	load: function(result, ioArgs) {
		console.log('load', result, ioArgs);
	},
	error: function(err, ioArgs) {
		console.log('error', err, ioArgs);
	}
});
// is not the same as:
dfd.then(function(result, ioArgs) {
	console.log('then', result, ioArgs); // ioArgs is undefined
}, function(err, ioArgs) {
	console.log('then', err, ioArgs); // ioArgs is undefined
});

[bill]

A Deferred represents a single (future) value, so (IIUC) it's not possible to pass a second parameter to then()'s callback function. Of course the Deferred's value could be an array like [result, ioArgs], but that would break backwards compatibility.

Does ioArgs have information besides what the app passed into dojo.xhrGet() in the first place?

[Simon Speich]

Replying to bill:

Does ioArgs have information besides what the app passed into dojo.xhrGet() in the first place?

Yes, I would like to access the ioArgs.xhr object

[Simon Speich]

Especially if you would like to pass back a custom (json) error message in the http body, then you would need access ioArgs.xhr.responseText

[fabioginzel]

+1

[kzyp]

Fixed in [25095]. Note that that responseText and status have always been available on the error object. The only things that were not previously available that is now available are response headers.

[fredfortier]

I see that this ticket is closed, but I am getting the same issue with Dojo 1.7.1. Is this still an open issue in 1.7.1? If not, what could I be missing?

var workItemDef = xhr.get( {

url : this._workplaceXtUrl + "/P8BPMREST/p8/bpm/v1/queues/" + queueName + "/stepelements/" + workObjectNumber, handleAs : "json"

}).then(function(data, ioargs) {

self.util.debug("printing the data object", [data, ioargs <--- FireBug tells me that ioargs is 'undefined']);

[bill]

I don't see how [25095] is related to this ticket at all. Kris' comment though is talking about the error callback (when the XHR fails), not the success callback. As I said above the success callback only gets one argument, so it's just a question of what that argument is. I think Bryan's work on dojo/request will handle this.

[psoares]

+1

[BryanForbes]

The requested functionality is already provided, albeit in a different place. If you use the return value from dojo/_base/xhr, it will have an ioArgs property on it. This is the same as the second argument to load and error:

var def = xhr.get({
   url: "foo"
});
def.then(function(text){
    console.log("Printing the data object", def.ioArgs);
});

Remember, however, that the return value of a chained then call will not be a deferred, but a promise. This means that the following will not work because of how Deferreds/Promises work:

var def = xhr.get({
    url: "foo"
}).then(function(text){
    console.log("Printing the data object", def.ioArgs);
});

def ends up being a promise because the Deferred from xhr.get has been chained off of.