retrieveValue

api.js

'use strict';
var CONSTS = require("./components/consts");
var _ = require("./components/utils");
var method = "GET";
var baseUrl;

var initialize = function(){
  baseUrl = buildEntrypoint(CONSTS.API.version,CONSTS.API.publisher.id);
};

var xhr = function() {
  var xhr = new XMLHttpRequest();
  return function(method, url, callback) {
    xhr.onreadystatechange = function() {
      if (xhr.readyState === 4) {
        if (typeof callback === "function") callback(xhr.responseText);
      }
    };
    xhr.open(method, url);
    xhr.send();
  };
}();

var getRecommendations = function(cb, state){
  var requiredQueries = ["app.type","app.apikey", "rec.count", "source.type", "source.id"];
  var flatObj = _.flatten(state);
  var url = buildEntrypoint(baseUrl, CONSTS.API.actions.get) + buildQueryStrings(requiredQueries, flatObj) + initPostfix(state);
  return xhr(method, url, cb);

};

var notifyClick = function(state, index){
  var requiredQueries = ["app.type", "app.apikey", "response.id", "response.session", "item.type", "item.id"];
  var item = state.data.list[index];
  var flatObj = _.extend(_.flatten(state), _.flatten({item: item}));
  var url = buildEntrypoint(baseUrl, CONSTS.API.actions.click) + buildQueryStrings(requiredQueries, flatObj);

  return xhr(method, url);

};

var notifyVisible = function(state){
  var requiredQueries = ["app.type", "app.apikey", "response.id", "response.session"];
  var flatObj = _.flatten(state);
  var url = buildEntrypoint(baseUrl, CONSTS.API.actions.visible) + buildQueryStrings(requiredQueries, flatObj);

  return xhr(method, url);
};



// HELPERS

function buildEntrypoint() {
  return Array.prototype.slice.call(arguments).join('/');
}

function retreiveValue(keys,obj){
  var val = obj;
  if(keys.indexOf(".") !== -1) {
    var subkeys = keys.split(".");
    for(var i=0 ; i<subkeys.length; i++) {
      val = val[subkeys[i]];
    }
    return val;
  }
  else {
    return obj[keys];
  }
}

function buildQueryStrings(keys, obj){
  var queries = [];
  keys.forEach(function(key){
    queries.push(key + "=" + encodeURIComponent(obj[key]));
  });

  return "?" + queries.join("&");
}

function initPostfix(state) {
  return state.session === "init" ? "&user.session=init" : "";
}


module.exports = {
  initialize: initialize,
  getRecommendations: getRecommendations,
  notifyClick: notifyClick,
  notifyVisible: notifyVisible
};