如何为每个用户通过函数进行Parse后台作业循环？

Question

我想要做的是让数据库中的每个User重复使用Parse后台作业循环，使用User个matchCenterItem，MComparisonArray和其他对象实例作为标准。

当我运行它时，会发生的事情是，不是按照我刚才描述的那样，使用matchCenterItem和MComparisonArray之类的所有实例来运行函数，因此函数不是能够区分用户。

如何正确地将此查询中的所有函数关联到每个用户，以便在他们保存新对象时：

var mComparisonArray = Parse.Object.extend("MComparisonArray");
 var newMComparisonArray = new mComparisonArray();
 newMComparisonArray.set('Name', 'MatchCenter');
 newMComparisonArray.set('MCItems', eBayResults);
 newMComparisonArray.set("parent", Parse.User());

它会将用户显示为父级，而不是在没有父级的情况下保存用户。

   Parse.Cloud.job("MatchCenterBackground", function(request, status) {

  console.log('background task started');

  //Query through all users 
  var usersQuery = new Parse.Query(Parse.User);

  //For every user, do the following:
  usersQuery.each(function(user) {
    //query through all their matchCenterItems
    var matchCenterItem = Parse.Object.extend("matchCenterItem");
    var query = new Parse.Query(matchCenterItem);

    // promise and searchterm arrays to be filled
    var promises = [];
    var searchTerms = [];

    //setting the limit of items at 10 for now
    query.limit(10);
    console.log('about to start the matchCenterItem query');

    return query.find().then(function(results) {

      console.log('matchCenterItem query results:' + results);
      if (results.length > 0) {
        console.log('we have entered the matchcenteritem query');

        for (i = 0; i < results.length; i++) {

          console.log('we have also entered the loop inside the matchCenterItem query');
          // later in your loop where you populate promises:
          var searchTerm = results[i].get('searchTerm');
          // add it to the array just like you add the promises:
          searchTerms.push(searchTerm);

          url = 'http://svcs.ebay.com/services/search/FindingService/v1';
          //push function containing criteria for every matchCenterItem into promises array
          promises.push((function() {

            if (results[i].get('itemLocation') == 'US') 
            {
              console.log('americuh!');
              var httpRequestPromise = Parse.Cloud.httpRequest({
                url: url,
                params: {
                  'OPERATION-NAME': 'findItemsByKeywords',
                  'SERVICE-VERSION': '1.12.0',
                  'SECURITY-APPNAME': '*APP ID GOES HERE*',
                  'GLOBAL-ID': 'EBAY-US',
                  'RESPONSE-DATA-FORMAT': 'JSON',
                  'REST-PAYLOAD&sortOrder': 'BestMatch',
                  'paginationInput.entriesPerPage': '3',
                  'outputSelector=AspectHistogram&itemFilter(0).name=Condition&itemFilter(0).value(0)': 'New',
                  'itemFilter(0).value(1)': results[i].get('itemCondition'),
                  'itemFilter(1).name=MaxPrice&itemFilter(1).value': results[i].get('maxPrice'),
                  'itemFilter(1).paramName=Currency&itemFilter(1).paramValue': 'USD',
                  'itemFilter(2).name=MinPrice&itemFilter(2).value': results[i].get('minPrice'),
                  'itemFilter(2).paramName=Currency&itemFilter(2).paramValue': 'USD',
                  'itemFilter(3).name=LocatedIn&itemFilter(3).value': 'US',
                  'itemFilter(4).name=ListingType&itemFilter(4).value': 'FixedPrice',
                  'keywords': results[i].get('searchTerm'),
                }
              });
            } 

            else if (results[i].get('itemLocation') == 'WorldWide') 
            {
              console.log('Mr worlwide!');
              var httpRequestPromise = Parse.Cloud.httpRequest({
                url: url,
                params: {
                  'OPERATION-NAME': 'findItemsByKeywords',
                  'SERVICE-VERSION': '1.12.0',
                  'SECURITY-APPNAME': '*APP ID GOES HERE*',
                  'GLOBAL-ID': 'EBAY-US',
                  'RESPONSE-DATA-FORMAT': 'JSON',
                  'REST-PAYLOAD&sortOrder': 'BestMatch',
                  'paginationInput.entriesPerPage': '3',
                  'outputSelector=AspectHistogram&itemFilter(0).name=Condition&itemFilter(0).value(0)': 'New',
                  'itemFilter(0).value(1)': results[i].get('itemCondition'),
                  'itemFilter(1).name=MaxPrice&itemFilter(1).value': results[i].get('maxPrice'),
                  'itemFilter(1).paramName=Currency&itemFilter(1).paramValue': 'USD',
                  'itemFilter(2).name=MinPrice&itemFilter(2).value': results[i].get('minPrice'),
                  'itemFilter(2).paramName=Currency&itemFilter(2).paramValue': 'USD',
                  // 'itemFilter(3).name=LocatedIn&itemFilter(3).value' : 'US',
                  'itemFilter(3).name=ListingType&itemFilter(3).value': 'FixedPrice',
                  'keywords': results[i].get('searchTerm'),
                }
              });
            }

            return httpRequestPromise;
          })());
        }
      }

      //when finished pushing all the httpRequest functions into promise array, do the following  
      return Parse.Promise.when(promises).then(function(results) {
        console.log('were in the when.then of promise');

        var eBayResults = [];
        // piece together eBayResults 
        for (var i = 0; i < arguments.length; i++) {
          var httpResponse = arguments[i];
          // since they're in the same order, this is OK:
          var searchTerm = searchTerms[i];
          // pass it as a param:
          var top3 = collectEbayResults(httpResponse.text, searchTerm);
          eBayResults.push(top3);
        }

        // collects ebay responses for every item in the form of top3 
        function collectEbayResults(eBayResponseText, searchTerm) {

          var ebayResponse = JSON.parse(eBayResponseText);
          //console.log('lets check eBayResults here:' + eBayResults);
          var matchCenterItems = [];

          //Parses through ebay's response, pushes each individual item and its properties into an array  
          ebayResponse.findItemsByKeywordsResponse.forEach(function(itemByKeywordsResponse) {
            itemByKeywordsResponse.searchResult.forEach(function(result) {
              result.item.forEach(function(item) {
                matchCenterItems.push(item);
              });
            });
          });

          var top3Titles = [];
          var top3Prices = [];
          var top3ImgURLS = [];
          var top3ItemURLS = [];

          //where the title, price, and img url are sent over to the app
          matchCenterItems.forEach(function(item) {
            var title = item.title[0];
            var price = item.sellingStatus[0].convertedCurrentPrice[0].__value__;
            var imgURL = item.galleryURL[0];
            var itemURL = item.viewItemURL[0];

            top3Titles.push(title);
            top3Prices.push(price);
            top3ImgURLS.push(imgURL);
            top3ItemURLS.push(itemURL);
          });

          console.log('about to define top3 value');
          console.log('btw ebay results is:' + eBayResults);

          var top3 = {
            "Top 3": [{
                "Title": top3Titles[0],
                "Price": top3Prices[0],
                "Image URL": top3ImgURLS[0],
                "Item URL": top3ItemURLS[0]
              },

              {
                "Title": top3Titles[1],
                "Price": top3Prices[1],
                "Image URL": top3ImgURLS[1],
                "Item URL": top3ItemURLS[1]
              },

              {
                "Title": top3Titles[2],
                "Price": top3Prices[2],
                "Image URL": top3ImgURLS[2],
                "Item URL": top3ItemURLS[2]
              },

              {
                "Search Term": searchTerm
              }
            ]
          };
          // return top3
        }


        //After all the above is done, eBayResults has presumably been constructed, and we will now make the comparisons

        //MatchCenter update checking goes here:
        console.log('the eBayResults length is:' + eBayResults.length);
        console.log('the eBayResults are:' + eBayResults);
        // Only check for new matches if user has matchCenterItems  
        if (eBayResults.length > 0) {
          console.log('yes the ebay results be longer than 0');

          //Query users MComparisonArray with the following criteria: 
          var mComparisonArray = Parse.Object.extend("MComparisonArray");
          var mComparisonQuery = new Parse.Query(mComparisonArray);

          mComparisonQuery.contains('Name', 'MatchCenter');
          // mComparisonQuery.contains("MCItems", eBayResults);

          console.log('setup query criteria, about to run it');
          return mComparisonQuery.find().then(function(results) {
            console.log('eh2:' + results);
            // No new items                      
            if (results.length > 0) {
              console.log("No new items, you're good to go!");
            }
            // New items found
            else if (results.length == 0) {

              console.log('no matching mComparisonArray, lets push some new shit');
              //replace MCItems array with contents of eBayResults
              Parse.Object.destroyAll(mComparisonArray);

              var newMComparisonArray = new mComparisonArray();
              newMComparisonArray.set('Name', 'MatchCenter');
              newMComparisonArray.set('MCItems', eBayResults);
              newMComparisonArray.set("parent", Parse.User());

              console.log('yala han save il hagat');
              // Save updated MComparisonArray  
              newMComparisonArray.save().then({
                success: function() {
                  console.log('MComparisonArray successfully created!');
                  //status.success('MComparisonArray successfully created!');
                },
                error: function() {
                  console.log('MComparisonArray error!!!');
                  //status.error('Request failed');
                }
              });
                  //send push notification

            }
              // status.success('MatchCenter Comparison Success!');
          },
            function(err) {
               console.log('nah no results for you bro:' + err); 
            });
        }



      });



    });
  }).then(function() {
    // Set the job's success status
    status.success("background job worked brah!");
  }, function(error) {
    // Set the job's error status
    status.error('DAMN IT MAN');
  });
});

Answer 1

快速浏览一下，我猜这是一个关闭的问题，我看到你使用内联函数保护了部分代码但不是全部保护。

我建议将代码分解为函数并调用它们，这不仅可以使代码更易于阅读和维护，还可以保护您免受闭包问题的影响，例如：

Parse.Cloud.job("MatchCenterBackground", function(request, status) {
    // ... other code to setup usersQuery ...

    usersQuery.each(function (user) {
        return processUser(user);
    }).then(function() {
        status.success("background job worked brah!");
    }, function(error) {
        status.error(error);
    });
});
// process user, return promise
function processUser(user) {
    // ... code to setup per-user query ...

    // easy way to share multiple arrays
    var shared = {
        promises: [],
        searchTerms: [],
    };

    return query.find().then(function(results) {
        // process results, populate shared data (promises and searchTerms)
        buildEbayRequestPromises(results, shared);
    }).then(function() {
        // process promises, return query promise
        return Parse.Promise.when(shared.promises).then(function() {
            // process the results of the promises, returning a query promise
            // ... code here ...
        });
    });
}
// process matchCenterItem results to build eBay promises
function buildEbayRequestPromises(results, shared) {
    // ... code that pushes items into shared.promises and shared.searchTerms ...
}

我还没有包括所有级别，但是您应该能够从如何更容易理解正在发生的事情的样本中获得一个想法。

作为一般规则，我喜欢将每个函数保留在不超过一个代码的屏幕上，如果它超过了我尝试将其分解为函数的话。