server_data_source.js

  fetchRecords: function(store, fetchKey, params) {
  	var ret = [], idx, len, id, recordType, rec, url, request, datasource ;
  	
  	datasource = this ; 
  	len = params.length ;
  	
  	for(idx = 0; idx < len; idx++) {
			storeKey = params[idx] ; // storeKey
  		id = store.idFor(storeKey) ; // record id
  		recordType = store.recordTypeFor(storeKey) ;
			rec = store.find(recordType, id) ; // specific record found by id
			url = rec.get('resourceURL') ; // resource url
			ret.push(storeKey) ; // return array of storeKeys
			
			request = SC.Request.getUrl(url) ;
			request.set('isJSON', YES) ;
			request.addObserver('response', function(r) { datasource.fetchRecordsDidComplete(r, store, storeKey)}) ;
			request.send() ;
  	}
  	
    return ret; // return array of storeKeys
  },
  
  fetchRecordsDidComplete: function(r, store, storeKey) {
  	var response ;
  	response = r.response() ;
  	store.dataSourceDidComplete(storeKey, response) ;
  }