如何使用JSON和jQuery在Rails 2.3.5中显示服务器错误

I've got in-place editing on a page in my app (using Rails 2.3.5 and jQuery). I want to know how to display an error on the page when the update fails.

我在我的应用程序的页面上进行了就地编辑（使用Rails 2.3.5和jQuery）。我想知道更新失败时如何在页面上显示错误。

I'm using ajax (an XMLHttpRequest) to save an update to a Comment object. The controller has an update method like this:

我正在使用ajax（XMLHttpRequest）来保存对Comment对象的更新。控制器有一个像这样的更新方法：

def update
  @comment = Comment.find(params[:id])
  respond_to do |format|
    # if @comment.update_attributes!(params[:comment])
    if false #deliberately forcing a fail here to see what happens
      format.json { render :nothing =>  true }
    else
      format.json { render :json => @comment.errors, :status => :unprocessable_entity }
    end
  end
end

In Firebug, I can see the server returns a "422" (an appropriate validation error status code). But it's a response to an XMLHttpRequest so there is no redirect to an error page.

在Firebug中，我可以看到服务器返回“422”（相应的验证错误状态代码）。但它是对XMLHttpRequest的响应，因此没有重定向到错误页面。

I think I actually want to do this:

我想我其实想要这样做：

format.json { render :json => @comment.errors}

or maybe this:

或者这个：

format.json {render :json => { :status => :error, :message => "Could not be saved" }.to_json, :status => 400 }

and trigger some Javascript function that iterates through (and displays) any errors.

并触发一些迭代（并显示）任何错误的Javascript函数。

I'm using a rails plugin REST in Place to implement the in-place editing. It doesn't appear to have any callback function to handle a failure. What are my options? Can I write some Javascript to respond to a failure condition without hacking the plugin? Do I have to hack the rest_in_place plugin to handle a failure condition? Is there a better plugin (for Rails or jQuery) that handles in-place editing, including failure conditions?

我正在使用rails插件REST来实现就地编辑。它似乎没有任何回调函数来处理故障。我有什么选择？我可以编写一些Javascript来响应失败情况而不破解插件吗？我是否必须破解rest_in_place插件来处理故障情况？是否有更好的插件（对于Rails或jQuery）处理就地编辑，包括失败条件？

UPDATE

UPDATE

This post from Peter Bui Standard JSON Response for Rails and jQuery was helpful in showing how to handle an error message from the server using XMLHttpRequest.status. I looked at his implementation of a blog using ajax paydro-talks. I'm surprised at the complexity required to handle a simple error condition. Usually Rails has all the goodness baked in but it seems server errors with JSON are out of scope. Can that be?

来自Peter Bui标准JSON响应Rails和jQuery的这篇文章有助于展示如何使用XMLHttpRequest.status处理来自服务器的错误消息。我用ajax paydro-talks查看了他对博客的实现。我对处理简单错误条件所需的复杂性感到惊讶。通常Rails已经完成了所有的好处，但似乎JSON的服务器错误超出了范围。可以吗？

I also looked at grimen's validatious-on-rails which accommodates models validations when ajax XMLHttpRequest is used. It's not clear to me how I'd use it to handle the general case of a "save" failing when validations succeed.

我还查看了grimen的validatious-on-rails，当使用ajax XMLHttpRequest时，它适用于模型验证。我不清楚如何在验证成功时使用它来处理“保存”失败的一般情况。

1 个解决方案

#1

I think your best option might be to just hack the plugin in this case, as it is really stupid that the plugin doesn't have an error handler anyway. hint: maybe tell the author of the plugin that it would be nice and useful to handle errors (what if connection fails or anything?? plugin will never know and no feedback for user).

我认为你最好的选择可能只是在这种情况下破解插件，因为插件没有错误处理程序真是愚蠢。提示：也许告诉插件的作者处理错误会很好和有用（如果连接失败或者什么？插件永远不会知道并且没有用户反馈）。

It should suffice if you add something like this around line 33 in jquery.rest_in_place.js after the success option

如果你在成功选项之后在jquery.rest_in_place.js中的第33行附近添加这样的东西就足够了

"error": function(xhr, state, error) {
  //do error handling here e.g.
  alert(state);
  //or $.parseJSON(xhr.responseText) and whatever or similar
}