在Ember.js 2.3中，如何将hasMany异步调用编译为ember中的一个调用，而不是多个？

Question

I'm upgrading to ember-cli and ember 2.3. Say I have a model called User and a model called Post , and a user ...

posts: DS.hasMany('post', {async:true})

Now, this works the way I expect it to, lazily loading data and not loading posts unless it is required in either the .js or the template. So when I do

{{#each user.posts as |post|}}
  {{post.title}}
{{/each}}

I get each post to render its title without a problem. However, in my server logs, I see this:

GET /posts/2
GET /posts/7
GET /posts/13

where the numbers are the post ids. This is to be expected, as when I return a user instance from the server, I return a list of the ids as the parameter 'posts'. So the user instance has:

...
'posts': '2,7,13'
...

in its data.

Now my question is this: way back when, when I used ember-data 1.0 (pre ember-cli and pre ember 1.13), I remember this call being made to the database instead for the same use case:

GET /posts?ids=2&7&13

or something along that line. I can't remember the exact format, but then, I could access the list of ids on the server side using this line of code:

var ids = req.query.ids.toString();

which gave me a comma separated list of ids (in string format). I would then convert this into the sql statement

SELECT * from posts where id in (2,7,13)

This SQL call was interpreted as a manyArray, I think, on the Ember Side and easily behaved as you would expect an Ember Array would.

How can I get this to happen again? I am quite confident that I am missing something and that I don't have to 'hack' ember-data; I would very much like to compress these calls into one instead of having an individual call to the database for each 'post'.

I should also mention that I am not looking to make {async:false} for these calls.

Answer 1

I think the thing you are looking for is coalesceFindRequests , this is a setting on your Adapter to tell Ember to bunch multiple requests that happen in the same runloop into one GET request as you had in the past.

You can see more detail here but essentially all you need to do is add the following to either your ApplicationAdapter (to enable it for all requests for all types) or to your posts adapter (so that it only affects the post requests)

Here is an example if you are using pod structure for your files (which I recommend)

// app/application/adapter.js
import DS from 'ember-data';

export default DS.JSONAPIAdapter.extend({
  coalesceFindRequests: true
})