一、概述
1. 在Ember Data上以每个实例为基础,records被持久化。在DS.Model的任何一个实例上调用save()并且它将产生一个网络请求。
2. 下面是一些例子:
var post = store.createRecord('post', {
title: 'Rails is Omakase',
body: 'Lorem ipsum'
}); post.save(); // => POST to '/posts'
store.findRecord('post', 1).then(function(post) {
post.get('title'); // => "Rails is Omakase" post.set('title', 'A new post'); post.save(); // => PUT to '/posts/1'
});
二、Promises
1. save()返回一个promise,所以它是非常容易处理成功和失败的情况的。这里是一个普遍的模式:
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
2. promises甚至使处理失败的网络请求变得容易:
var post = store.createRecord('post', {
title: 'Rails is Omakase',
body: 'Lorem ipsum'
}); var self = this; var onSuccess = function(post) {
self.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
3. 在这里 here你可以学到更多关于promises,但是这里是另外一个关于展示如何重试持久化的例子:
function retry(callback, nTimes) {
// if the promise fails
return callback().catch(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 - 1);
} // 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);