Question

英文原文：http://emberjs.com/guides/models/persisting-records/

Ember Data中的记录都基于实例来进行持久化。调用DS.Model实例的save()会触发一个网络请求，来进行记录的持久化。

下面是几个示例：

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var post = store.createRecord('post', { title: 'Rails is Omakase', body: 'Lorem ipsum' }); post.save(); // => POST to '/posts'

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var post = store.find('post', 1); post.get('title') // => "Rails is Omakase" post.set('title', 'A new post'); post.save(); // => PUT to '/posts/1'

承诺

save()会返回一个承诺，这使得可以非常容易的来处理保存成功和失败的场景。下面是一个通用的模式：

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var post = store.createRecord('post', { title: 'Rails is Omakase', body: 'Lorem ipsum' }); var self = this; function transitionToPost(post) { self.transitionToRoute('posts.show', post); } function failure(reason) { // handle the error } post.save().then(transitionToPost).catch(failure); // => POST to '/posts' // => transitioning to posts.show route

对于失败的网络请求，承诺也可以方便的来处理：

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var post = store.createRecord('post', { title: 'Rails is Omakase', body: 'Lorem ipsum' }); var onSuccess = function(post) { this.transitionToRoute('posts.show', post); }; var onFail = function(post) { // deal with the failure here }; post.save().then(onSuccess, onFail); // => POST to '/posts' // => transitioning to posts.show route

更多关于承诺的内容请参看这里，下面是一个示例展示了如何在重试失败的持久化操作：

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function retry(callback, nTimes) { // if the promise fails return callback().fail(function(reason) { // if we haven't hit the retry limit if (nTimes-- > 0) { // retry again with the result of calling the retry callback // and the new retry limit return retry(callback, nTimes); } // otherwise, if we hit the retry limit, rethrow the error throw reason; }); } // try to save the post up to 5 times retry(function() { return post.save(); }, 5);