Rails 3.1 ajax:success handling

问题:

So Im playing with CoffeeScript, Rails 3.1 all the good stuff. I have a resource with all the usual routes index, show, create, edit, update, destroy.

The index view has a form that uses :remote => true like so:

<%= form_for @todo, :remote => true do |f| %>
    <div class="field">
    <%= f.label :name %><br />
    <%= f.text_field :name %>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %> 

In the controller for create I have the following:

def create
    @todo = Todo.new(params[:todo])

    respond_to do |format|
      if @todo.save
        format.html { redirect_to @todo, notice: 'Todo was successfully created.' }
        format.json { render json: @todo, status: :created, location: @todo }
        format.js {render json: @todo }
      else
        format.html { render action: "new" }
        format.json { render json: @todo.errors, status: :unprocessable_entity }
      end
    end
  end

Im trying to not use .js.erb views as I would rather handle the JSON returned and do all the fancy appends to the todo list and so on. (It just feels cleaner to me).

In my todos.js.coffee I have used the following:

$(document).ready ->
    $("#new_todo")
      .bind "ajax:success", (event, data) ->
        alert("Ajax SUCCESS!!!")

(Yeah just tyting to open an alert box does not work) I tried loads but just cannot trigger this event. The request does complete successfully and the new todo is added.

Any help with this would be appreciated. Thanks

回答1:

Started to pour over the rails.js and wondered if any of the ajax: callbacks were being raise.

Turned out they were well the beforeSend and error... hang on... error? How could this be? The creation of the new todo happens successfully, the response is the JSON I expect. But on stepping through the callback code I notice an Invalid label error.

Quick google later brings me to this post http://blog.seqmedia.com/?p=484

Turns out the JSON is being returned as a string, Firbug got that and parsed it correctly so I could check the response. However rails.js and js in general didnt know how to handle the string and threw the above error (rather silently I may say).

The solution was in the respond_to

format.js {render json: @todo, content_type: 'text/json' }

A bit thanks to Trevor Burnham (like the book BTW) for his help and Amy from sequence media whose blog post ultimately gave me the solution.

回答2:

1. What is #new_todo? Does an element with that ID exist? Verify that $('#new_todo').length > 0 in your code, and that it's the right element to bind your event handler to.
2. What is ajax:success? The jQuery API defines an ajaxSuccess event (see the Ajax Events docs), but I've never seen the version with the colon before.