beforeSave causes Queries to return nothing

问题

I have a cloud function that takes in a request and creates objects as well as associates them in a chain of promises. Without a beforeSave this function works fine but the beforeSave exists to prevent duplicate entries of email addresses in the Email Class.

REQUEST

{
   "projectDescription": "Testing saveProject",
   "projectTitle": "This is only a test, in the event of a real post          this will have an actual description",
   "isEmailEnabled": true,
   "shareEmails": [
     "test1@gmail.com",
     "test2@gmail.com",
     "test3@gmail.com"
   ],
 "userId": "1234"
}

FUNCTION

Parse.Cloud.define("saveProject", function(request, response) {

    var emails = request.params.shareEmails;
    var user = request.params.userId;
    var projectDescription = request.params.projectDescription;
    var projectTitle = request.params.projectTitle;
    var emailStatus = request.params.isEmailEnabled;

    var ProjectClass = Parse.Object.extend("Project");

    var EmailsClass = Parse.Object.extend("Email");

    var EmailsClassAssignment = Parse.Object.extend("EmailAssignment");

    var project = new ProjectClass();

    var projectO;

    var emailQueryArray;

    project.set("title", projectTitle);
    project.set("createdBy", {
        "__type": "Pointer",
        "className": "_User",
        "objectId": user
    });
    project.set("description", projectDescription);
    project.set("status", true);
    project.set("emailShareEnabled", emailStatus);
    project.save().then(function(projectObject) {

        projectO = projectObject;
    }).then(function() {
        emails.forEach(function(emailAddress) {
            var email = new EmailsClass();

            email.set("address", emailAddress);
            email.save();
        });
    }).then(function() {

        emails.forEach(function(emailQuery) {
            var queryEmail = new Parse.Query("Email");

            queryEmail.equalTo("address", emailQuery);
            queryEmail.find().then(function(results) {
                emailObject = results;
                console.log(emailObject);
            });
        });
    });
});

beforeSave Code

Parse.Cloud.beforeSave("Email", function(request, response) {

var query = new Parse.Query("Email");


// Gets the email key value (string) before object is saved
query.equalTo("address", request.object.get("address"));

// Checks to see if an object for that email already exists
query.first({

  success: function(object) {
    if (object) {
        response.error("This email already exisits");
    } else {
      response.success();
    }
  },
  error: function(error) {
    response.error("Could not determine if this email exists");
  }
});
});

Is there a way to account for the beforeSave in the callback from saving the email object so that I ensure the object is there to query against?

I need the objects to be there so that I can get the Id for each and create a pointer in the Email assignments Class.

Would be happy to further explain any part of the code or function as a whole.

回答1:

save is, just like find, an asynchronous method. To wait until it they have completed, and to notice whether they have failed, you need to use Promise.when on all the promises that have been created in the loop. See Parse JavaScript Promises within Loop not Completing and similar questions.

Your code should look like this:

var ProjectClass = Parse.Object.extend("Project");
var EmailsClass = Parse.Object.extend("Email");
var EmailsClassAssignment = Parse.Object.extend("EmailAssignment");

Parse.Cloud.define("saveProject", function(request, response) {
    var emails = request.params.shareEmails;
    var user = request.params.userId;
    var projectDescription = request.params.projectDescription;
    var projectTitle = request.params.projectTitle;
    var emailStatus = request.params.isEmailEnabled;

    var project = new ProjectClass();
    project.set("title", projectTitle);
    project.set("createdBy", {
        "__type": "Pointer",
        "className": "_User",
        "objectId": user
    });
    project.set("description", projectDescription);
    project.set("status", true);
    project.set("emailShareEnabled", emailStatus);
    project.save().then(function() {
        return Parse.Promise.when(emails.map(function(emailAddress) {
//      ^^^^^^ ^^^^^^^^^^^^^^^^^^        ^^^
            var email = new EmailsClass();
            email.set("address", emailAddress);
            return email.save();
//          ^^^^^^
        }));
    }).then(function() {
        return Parse.Promise.when(emails.map(function(emailQuery) {
//      ^^^^^^ ^^^^^^^^^^^^^^^^^^        ^^^
            var queryEmail = new Parse.Query("Email");
            queryEmail.equalTo("address", emailQuery);
            return queryEmail.find().then(function(results) {
//          ^^^^^^
                console.log(results);
            });
        }));
    });
});

来源：https://stackoverflow.com/questions/28866144/beforesave-causes-queries-to-return-nothing