I needed to catch a possible login page in all responses from the server, so I have overridden Backbone.sync globally so I can check all errors before passing them on.
Backbone.originalSync = Backbone.sync;
Backbone.sync = function (method, model, options) {
var originalSuccess, originalError;
console.log("sync override...");
// remember original success so we can call it if user logs in successfully
originalSuccess = options.success;
// proxy the error callback to first check if we get a login page back
originalError = options.error;
options.error = function (model, xhr, options) {
if (xhr.status === 200 && xhr.responseText === "") {
// parse error from empty response (jq1.9 invalid json, ok)
originalSuccess(model, xhr, options);
} else {
console.log("Sync error " + statusTxt + ", " + thrown.message);
if (xhr.status === 200 || xhr.status === 302 || xhr.status === 0) {
// login page returned instead of json...
// open a new window with relogon.html to trigger a new login
window.showModalDialog("../relogon.html");
} else {
// normal error, pass along
if (originalError) {
originalError(model, xhr, options);
}
}
}
};
// call the original sync
Backbone.originalSync(method, model, options);
};
This broke miserably when going from 0.9.9 to 1.0. Looks like the original Backbone.sync wraps its error handlers differently, causing my error handler to be called first, with a jquery xhr signature. I had to change the signature of the error handler to this:
options.error = function (xhr, statusTxt, thrown) {
Ok so now it works, but I get the feeling that I am doing something wrong.
Is there a better way to do this?
I tried with jquery promises but I need to be able to switch from error state to success (when calling originalSuccess), which did not seem to work with promises.