How do I write a findMany that will get in chunks? - ember.js

Question

Ember 1.5.1
Ember-Data 1.0 beta 7
I've tried to modify the DS.ActiveModelAdapter's findMany so it'll get in chunks of 40... this is because I can't use the links feature and it seems to be generating 400 errors because it has too many ids in the URL its creating.
I tried using this adapter, but I keep getting error messages that look like this:
Error: Assertion Failed: Error: no model was found for 'super'
Here's my Adapter:
App.ApplicationAdapter = DS.ActiveModelAdapter.extend({
findMany: function(store, type, ids) {
self = this;
return new Ember.RSVP.Promise(function(resolve, reject) {
var idsPerRequest = 40;
var totalIdsLength = ids.length;
var numberOfBins = Math.ceil( totalIdsLength / idsPerRequest ); // number per bin
var bins = [];
ids.forEach( function(someId, index) {
var thisBinIndex = index % numberOfBins;
var thisBin = Ember.A( bins[thisBinIndex] );
thisBin.pushObject(someId);
bins[thisBinIndex] = thisBin;
});
var requestPromises = bins.map(function(binOfIds) {
return self.ajax(self.buildURL(type.typeKey), 'GET', { data: { ids: binOfIds } });
});
Ember.RSVP.all(requestPromises).then(function(resolvedBinRequests) {
var resolvedObjects = Em.A([]);
resolvedBinRequests.forEach(function(resolvedBin) {
resolvedObjects.addObjects(resolvedBin);
});
resolve(resolvedObjects);
}, function(error) {
reject(error);
});
});
}
});
Can anyone help me out with this? It'd be really appreciated. Am I just missing something obvious or have I perhaps done something silly?
Thanks in advance!
[edit] Okay so further to this I've figured out why it's not working, and that's because the response that's coming back is a promise for the JSON payload, but what I'm doing is joining multiples of these into an array and returning that... which obviously won't be right... but what I need to do is merge the arrays inside the objects returned into one, I think (in concept)... I'm not really sure how to do this in actuality, though... I've tried various things, but none of them seem to work well... :(

Answer 1

I'm not sure how much control you have over the back-end, but this seems like a perfect use case for using links instead of returning all of the ids.
App.Foo = DS.Model.extend({
bars: DS.hasMany('bar', {async:true})
});
App.Bar = DS.Model.extend({
name: DS.attr()
});
Then when you query for foo your json returns a link instead of a list of ids
{
foo: {
id:1,
links: {
bars: '/foo/1/bars' // or anything, you could put /bars?start=1&end=9000
}
}
}
Here's an example with 1000 relationship records hitting a simple endpoint:
http://emberjs.jsbin.com/OxIDiVU/579/edit

Answer 2

Okay so I finally worked out how to make this work.
I'll share my answer here for future posterity ;-)
Of interest is that the required response had to be a promise and it had to contain a straight up JS object, so I "munged" all the responses into one JS object and manually built the pluralized camelized type key... I wasn't sure how else to do this. So... sorry it's so hacky, but this actually works and lets me fix my app for now until the "links" feature is working again.
App.ApplicationAdapter = DS.ActiveModelAdapter.extend({
findMany: function(store, type, ids) {
self = this;
return new Ember.RSVP.Promise(function(resolve, reject) {
var idsPerRequest = 40;
var totalIdsLength = ids.length;
var numberOfBins = Math.ceil( totalIdsLength / idsPerRequest ); // number per bin
var bins = [];
ids.forEach( function(someId, index) {
var thisBinIndex = index % numberOfBins;
var thisBin = Ember.A( bins[thisBinIndex] );
thisBin.pushObject(someId);
bins[thisBinIndex] = thisBin;
});
// build an array of promises, then resolve using Ember.RSVP.all
var requestPromises = bins.map(function(binOfIds) {
return self.ajax(self.buildURL(type.typeKey), 'GET', { data: { ids: binOfIds } });
});
// build the required return object, which is a promise containing a plain JS object
// note this can't be an Ember object
Ember.RSVP.all(requestPromises).then(function(resolvedBinRequests) {
var pluralizedDecamelizedTypeKey = type.typeKey.decamelize().pluralize();
var resolvedObjects = Em.A([]);
var returnObject = {};
returnObject[pluralizedDecamelizedTypeKey] = resolvedObjects;
resolvedBinRequests.forEach(function(resolvedBin) {
var theArray = resolvedBin[pluralizedDecamelizedTypeKey];
resolvedObjects.addObjects(theArray);
});
var responsePromise = Ember.RSVP.Promise.cast(returnObject);
resolve(responsePromise);
}, function(error) {
reject(error);
});
});
}
});

Answer 3

After some feedback I updated this response to attempt to extract the response payloads in the serializer instead of attempting to mimic the store's logic in the adapter.
http://emberjs.jsbin.com/wegiy/60/edit
App.ApplicationAdapter = DS.ActiveModelAdapter.extend({
findMany: function(store, type, ids) {
// build an array of promises, then resolve using Ember.RSVP.all
var idsPerRequest = 40;
var totalIdsLength = ids.length;
var numberOfBins = Math.ceil( totalIdsLength / idsPerRequest ); // number per bin
var bins = [];
ids.forEach( function(someId, index) {
var thisBinIndex = index % numberOfBins;
var thisBin = Ember.A( bins[thisBinIndex] );
thisBin.pushObject(someId);
bins[thisBinIndex] = thisBin;
});
var requestPromises = bins.map(function(binOfIds) {
return self.ajax(self.buildURL(type.typeKey), 'GET', { data: { ids: binOfIds } });
});
return Ember.RSVP.all(requestPromises);
}
});
App.ApplicationSerializer = DS.ActiveModelSerializer.extend({
extractFindMany: function(store, type, responsePayloads) {
// responsePayloads is the resolved value from the Ember.RSVP.all(requestPromises) promise
var serializer = this;
var extractedResponses = responsePayloads.map(function(payload) {
return serializer.extractArray(store, type, payload);
});
// extractedResponses is an array of arrays. We need to flatten it into 1 array.
return [].concat.apply([], extractedResponses);
}
});