Parse: Update Object From Cloud Code

I have created a background job to run every minute. The purpose of it is to delete old or outdated data within the database. In this case, the user submits a time which has an att

Solution 1:

The essential part of the answer is that object properties can be set with set() and objects are saved with save(). Here's a quick example of just that...

// say object is some object that's been retrieved from the databasevar times = object.get("times");
    var timestamps = object.get("timestamp");  // would be better to make the array name plural in the database// do whatever you want to the arrays here, then ...object.set("times", times);
    object.set("timestamp", timestamps);
    return results[0].save();
}).then(function(result) {
        response.success("success");
}, function(error) {
        response.error(error);
});

But I understand you really want to do this for many Wait objects, so we're going to need a stronger design. Let's start getting into the habit of building functions that do logical chunks of work. Here's one that fixes those arrays for a given Wait object...

// delete parts of the waitObject time arrays prior to currentTimefunction removeOldWaitTimes(waitObject, currentTime) {
    var times = waitObject.get("times");
    var timestamps = waitObject.get("timestamp");
    for (var i = 0; i < timestamps.length; i++) {
        if (currentTime >= timestamps[i] + 3600) {
            // Delete old wait times
            timestamps.splice(i, 1);
            times.splice(i, 1);
            i--;
        } else {
            break;
        }
    };
    waitObject.set("times", times);
    waitObject.set("timestamp", timestamps);
}

We need to call this in a loop, for each Wait object found. When we're done, we need to save all of the objects that were changed...

Parse.Cloud.job("expireTimes", function(request, response){
    Parse.Cloud.useMasterKey();
    var currentTime = newDate().getTime() / 1000;
    var query = newParse.Query("Wait");
    query.find().then(function(results) {
        for (var i=0; i<results.length; i++) {
            removeOldWaitTimes(results[i], currentTime);
        }
        returnParse.Object.saveAll(results);
    }).then(function(result) {
        response.success("success");
    }, function(error) {
        response.error(error);
    });
});

Please note that as the number of objects in the Wait class grows large, the job might get too long or the query (which can be set to a max limit of 1k objects returned) might miss results. We'll need to improve the query if that becomes a risk. (e.g. if the job runs every hour, there's no reason to retrieve Wait objects that were updated more than an hour ago).

EDIT say you want to update some as above, and destroy others. You'll need to handle two promises to do that...

Parse.Cloud.job("expireTimes", function(request, response){
    Parse.Cloud.useMasterKey();
    var destroyThese = [];
    var currentTime = new Date().getTime() / 1000;
    var query = new Parse.Query("Wait");
    query.find().then(function(results) {
        var updateThese = [];
        for (var i=0; i<results.length; i++) {
            var result = results[i];
            if (result.get("times").length > 0) {
                removeOldWaitTimes(result, currentTime);
                updateThese.push(result);
            } else {
                destroyThese.push(result);
            }
        }
        return Parse.Object.saveAll(updateThese);
    }).then(function(result) {
        return Parse.Object.destroyAll(destroyThese);
    }).then(function(result) {
        response.success("success");
    }, function(error) {
        response.error(error);
    });
});

We place destroyThese array in the enclosing scope so that it is available to the next step in the chain of promises.

Solution 2:

Currently, i didn't find the best solution, but it's working for me now.

var Progress = Parse.Object.extend(PROGRESS);
var progressQuery = new Parse.Query(Progress);
progressQuery.equalTo("userId", userId)
progressQuery.find({
    success: function (progress){
        for (i = 0; i < progress.length; i++){
            progress[i].set("lastUse", false)
            progress[i].save()
        }

    },
    error: function(object, error) {
        console.log(error)
    }
})