编辑Backbone Ajax成功方法以添加自定义错误处理

Question

I have my own custom error code inside of a backbone ajax success method in case the server returns an error. The problem is that this code is repeated throughout my app and I wanted to edit the success function in one place so I don't have to constantly repeat this error handler in every ajax success. I want to edit the success function to include this error check wrapper. Do you know how to do that?

Here is an example of my success method in one of my views:

"success" : function success(model, data)
             {
              if(data['error'] !== undefined && data['error'].length === 0)
               {
                message('error', 'Whoops! System Error. Please refresh your page.');
               }
              else if(data['error'] !== undefined)
               {
                message('error', data['error']);
               }
              else
               {
                //add templates and do stuff here
               }
             },

Ideally I'd like to set that in a config somewhere and then I'd just be able to use:

"success" : function success(model, data)
             {
              // add templates and do stuff here
             }

Is this possible? I tried using ajaxSetup but that didn't seem to work for me.

UPDATED CODE STILL NOT WORKING:

That does get me a little further along but the error handler isn't functioning as a wrapper. The data is not being passed into my ajax calls. In fact, my success methods on my ajax calls aren't running at all anymore. I tried console.log("some text") in my ajax calls but nothing is being output. Do you know what is wrong with this?

// Save the original Sync method
defaultSync = Backbone.sync;

//Over ride Backbone async
Backbone.sync = function(method, 
                         model, 
                         options) 
                 {
                  success = options.success

                  options.success = function(data) 
                                     {
                                      if(data['error'] !== undefined && data['error'].length === 0)
                                       {
                                        message('error', 'Whoops! System Error. Please refresh your page.');
                                       }
                                      else if(data['error'] !== undefined)
                                       {
                                        message('error', data['error']);
                                       }
                                      else
                                       {
                                        success(model, 
                                                data);
                                       }
                                     }

                  return defaultSync(method, 
                                     model, 
                                     options)
                 }

Answer 1

There are two ways to solve this:

• Inheriting Backbone Model

You could create your own custom model which inherits from Backbone Model. In it you could override the save method. Read Backbone docs on how to extend their model

In your custom save method, you will call the save method of super, check the responseText, if it's success then you'll call the success callback. (please do read backbone docs on how to call a method of your parent model in Javascript)

• Override Backbone.Sync

Backbone has a Sync module which basically by default makes all ajax requests, parses the response and then calls the success/error callbacks you specified when calling save on your model. It's pretty simple. Take a look at this doc . Again you could override this, do exactly what Backbone is doing by default but only call the success/error callbacks based on responseText you received.

UPDATE: Sample Code (warning code not tested)

//Over ride Backbone async

defaultSync = Backbone.Sync // Save the original Sync method. We'll be needing that.

Backbone.Sync = function(method, model, options) {
   success = options.success
   error = options.error

   options.success = function(model, data, options) {
      if (/% all your custom checks are true */) {
           success (model, data, options);
      }
      else {
         error(model,data,options);
     }
    }

   return defaultSync(method, model, options);

}

Please make sure with this strategy the Sync method will be overriden for ALL your Backbone sync. If you don't want that then use Model#save override.

Take a look at this code where I am overriding Backbone.Sync to make it work with Parse.com API.