Records in Ember Data are persisted on a per-instance basis.
Call save()
on any instance of DS.Model
and it will make a network request.
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。
Here are a few examples:
下面是几个示例:
var post = store.createRecord('post', {
title: 'Rails is Omakase',
body: 'Lorem ipsum'
});
post.save(); // => POST to '/posts'
var post = store.find('post', 1);
post.get('title') // => "Rails is Omakase"
post.set('title', 'A new post');
post.save(); // => PUT to '/posts/1'
Promises
承诺
save()
returns a promise, so it is extremely easy to handle success and failure scenarios.
Here’s a common pattern:
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:
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
Promises even make it easy to work with failed network requests:
对于失败的网络请求,承诺也可以方便的来处理:
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
You can read more about promises here, but here is another example showing how to retry persisting:
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:
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);