I'm a little confused about where to place a response.success() when using serial Promises.
Here's the situation: I've got a cloud function that accepts an array of email addresses and the current user. The function does the following:
Finds the current user based upon it's user object id.
Iterates over the array of emails addresses
Find if there is an existing user for each given email address
If there is an existing user, we check to see if the existing user and the current user are friends
If they are not friends, it creates a friendship.
Now when I run this function without a response.success(), it does exactly what I expect it to and the friendships entries are created. But no matter where I place the response in the code, I get the resulting response.success message and none of the serialized promises execute.
Why the resulting success/failure matters: I'm executing this function from an iOS app and I'd like to properly handle the success or failure cases correctly on the iOS side.
Here is the cloud function:
Parse.Cloud.define("friendExistingUsers", function(request, response) {
// Get our parameters
var addresses = request.params.emailAddresses;
var userId = request.params.user;
// Query for our user
var userQuery = new Parse.Query("User");
userQuery.equalTo("objectId", userId)
userQuery.first().then(function(currentUser) {
// if we find the user, walk the addresses
var promise = Parse.Promise.as("success");
_.each(addresses, function(address) {
console.log(address);
// add a then to our promise to handle whether a relationship is
// being created.
promise = promise.then(function() {
// find if there is a user for that address
var emailQuery = new Parse.Query("User");
emailQuery.equalTo("email", address);
emailQuery.first().then(function(addressUser) {
if (typeof addressUser != 'undefined') {
// found one.
console.log(addressUser);
// figure out if our current user and this user are
// friends.
var friendQuery = new Parse.Query("FVFriendship");
friendQuery.equalTo("from", currentUser);
friendQuery.equalTo("to", addressUser);
friendQuery.first().then(function(relationship) {
if (typeof relationship != 'undefined') {
// if they are, we need to pass.
console.log("Found a relationship: " = relationship)
} else {
// They are not. Add the friendship
var Friendship = Parse.Object.extend("FVFriendship");
var friendship = new Friendship();
friendship.set("from", currentUser);
friendship.set("to", addressUser);
friendship.save().then(function(result) {
console.log("Created a friendship: " + result)
});
};
});
} else {
// we did not find a user for that address
console.log("No user for " + address);
};
});
});
});
console.log(promise);
return promise;
}).then(function() {
response.success("success");
});
});
Thanks in Advance. Let me know if there's anything else I can add.
Your .then callback function attached to promise should return a promise. Missing this is a common mistake when using promises.
Also Parse doesn't seem to show objects with console.log as browsers do, so I wrap them into JSON.stringify().
Related
I am trying to send a Push Notification through Parse Cloud Code when a certain object has been modified - "dirty"
I think I am almost there, but received an error because I believe am creating a new user instead of querying for one.
Parse.Cloud.beforeSave("Fact", function(request, response) {
var dirtyKeys = request.object.dirtyKeys();
for (var i = 0; i < dirtyKeys.length; ++i) {
var dirtyKey = dirtyKeys[i];
if (dirtyKey === "isValid") {
//send push
// Creates a pointer to _User with object id of userId
var targetUser = new Parse.User();
// targetUser.id = userId;
targetUser.id = request.object.userID;
var query = new Parse.Query(Parse.Installation);
query.equalTo('user', targetUser);
Parse.Push.send({
where: query,
data: {
alert: "Your Fact was approved :)"
}
});
return;
}
}
response.success();
});
I found this post related to my problem. My question now is how to integrate the user query in my beforeSave block. Ideally I would create another function for the user query and place that in my beforeSave block.
**5/14 Update
I took #toddg's advice and fixed the before save. Here is a clearer picture of what I am trying to do and the new error.
A couple points (as #Subash noted in the comments) before I get into the code:
Parse.Push.send is an async operation, so you'll want to ensure you call response.success() after your push send completes. I'm going to deal with this using Promises, as I think they are more flexible than callbacks. If you're not familiar, read about them here
The return in your if statement will likely prevent the response.success() from being called.
Here's my recommended way of doing it:
Parse.Cloud.beforeSave("Fact", function(request, response) {
// Keep track of whether we need to send the push notification
var shouldPushBeSent = false;
var dirtyKeys = request.object.dirtyKeys();
for (var i = 0; i < dirtyKeys.length; ++i) {
var dirtyKey = dirtyKeys[i];
if (dirtyKey === "isValid") {
shouldPushBeSent = true;
}
}
if (shouldPushBeSent) {
//send push
// Creates a pointer to _User with object id of userId
var targetUser = new Parse.User();
// targetUser.id = userId;
targetUser.id = request.object.userId;
var query = new Parse.Query(Parse.Installation);
// We want to pass the User object to the query rather than the UserId
query.equalTo('user', targetUser);
Parse.Push.send({
where: query, // Set our Installation query
data: {
alert: "Your fact was approved"
}
}).then(function(){
// Now we know the push notification was successfully sent
response.success();
}, function(error){
// There was an error sending the push notification
response.error("We had an error sending push: " + error);
});
} else {
// We don't need to send the push notification.
response.success();
}
});
By the way, I'm assuming that you have a column on your Installation class that tracks which user is associated with each Installation.
I have a setup with Three relevant classes: _User, Article, and Profile. In Article I have a pointer named author for _User, and in Profile, I have the same; a pointer, but named user, for _User.
Now, I want to retrieve data from Article, with the cols firstname and lastname in Profile, where the pointer in Article matches the objectId in _User, and the pointer in Profile.
Basically what I would solve with an inner join in SQL.
How do I go about this with just one parse call?
This is what I have so far:
var Article = Parse.Object.extend("Article");
var query = new Parse.Query(Article);
query.include("category");
query.find({
success: function(results) {
console.log("Successfully retrieved " + results.length + " article(s):");
// Do something with the returned Parse.Object values
for (var i = 0; i < results.length; i++) {
var object = results[i];
console.log(object.get('title'));
console.log(object.get('content'));
console.log(object.get('category').get("categoryName"));
}
},
error: function(error) {
console.log("Error: " + error.code + " " + error.message);
}
});
Its a pleasure answering questions where the OP took the trouble to include a complete (and minimal) description of the data and the desired result.
I think I understand that you want to get Articles, and for each you want to get Profiles, and that the Profiles and articles are (logically) joined via a common pointer to User.
This can be done using an additional query per article. For clarity and maintainability, I like to break these things up into short, logical promise-returning functions, so...
// for handy array functions, like _.map, and turning var args into simple arrays
var _ = require('underscore');
// note: include underscore this way in cloud code (nodejs)
// for browser, see underscorejs.org to add to your project
// this will answer a promise that is fulfilled with an array of the form:
// [ { article:article_object, profile:profile_object }, {...}, ...]
function articlesWithProfiles() {
var query = new Parse.Query("Article");
query.include("category");
query.include("author");
return query.find().then(function(articles) {
var promises = _.map(articles, function(article) {
return profileForArticle(article);
});
return Parse.Promise.when(promises);
});
}
// return a promise that's fulfilled by associating the given article with it's profile
function profileForArticle(article) {
var author = article.get("author");
var query = new Parse.Query("Profile");
query.equalTo("user", author);
return query.first().then(function(profile) {
return { article:article, profile:profile };
});
}
// call it like this
articlesWithProfiles().then(function() {
// see edit below
var result = _.toArray(arguments);
console.log(JSON.stringify(result));
}, function(error) {
// handle error
console.log(JSON.stringify(error));
});
I just can't seem to get a hang of JavaScript promises.
In Parse, I have an attribute on a user that stores an array of Facebook friends IDs. When a new user logs in through Facebook for the first time I want to iterate through their Facebook friends that are using the app, then update those user's Facebook friends array to include this new user.
So... in user before_save I have this:
var friendsArray = user.get("facebookFriends");
// Iterate through all Facebook friends
_.each(friendsArray, function(facebookId){
// Retrieve the Facebook friend user
var query = new Parse.Query(Parse.User);
query.equalTo("facebookId", facebookId);
console.log("this executes");
query.find().then( function(){
var user = results[0];
// This does not execute
console.log("Need to update " + user.get("displayName") + "'s facebook friends");
return Parse.Promise.as();
});
}
My problem is not that different than another previous problem I encountered (Parse JavaScript SDK and Promise Chaining), except that this time I need the results of the async call before I can begin updating the user's Facebook friends array.
The way to accomplish this is with Parse.Promise.when() which is fulfilled when array of promises passed to it are fulfilled. And the loop can be made prettier as _.map().
var friendsArray = user.get("facebookFriends");
var findQs = _.map(friendsArray, function(facebookId){
// Retrieve the Facebook friend user
var query = new Parse.Query(Parse.User);
query.equalTo("facebookId", facebookId);
console.log("this executes");
return query.find();
});
return Parse.Promise.when(findQs).then(function(){
var user = results[0];
// This will work now
console.log("Need to update " + user.get("displayName") + "'s facebook friends");
return Parse.Promise.as();
});
The results will be an array of arrays -- since find returns an array --passed as var-args, and underscore _.toArray() is useful here, i.e.
return Parse.Promise.when(finds).then(function() {
var individualFindResults = _.flatten(_.toArray(arguments));
// and so on
I am currently working on my own project, based on the discover meteor book.
I have subscriptions of my collection 'posts'.
I am using easy-search (a search package), and currently having some troubles.
I have easy search on a overlay called in with javascript.
When I search, it will always return the posts included in the subscriptions + search result as the result.
For example, if I'm in the post lists page, if I search for Chocolate, the result would be every posts in the post list page + chocolate keyword posts.
It goes the same for single post pages.
I was wondering if I could unsubscribe temporarily with a click event. In this case, would be the search button.
Don't use Meteor.publish for searching.
Create a Meteor.method on the server instead to find the search results.
Create a client-only (unmanaged) collection var results = new Mongo.Collection(null)
When you perform the search, remove all results results.remove({}) and then insert the results from the Meteor.method callback.
Then, to stop each search waiting until the next one completes (bad for autocomplete), you can look at calling the Meteor.method with wait: false eg.
Meteor.apply('mySearchMethod',[parameters], {wait: false}, function(err, res){});
To make this work, you need to call this.unblock() inside the search method.
Example Code
var searching = new ReactiveVar(false);
var currentSearch = "";
var results = new Mongo.Collection(null);
var search = function(searchText){
searchText = searchText.trim();
if (searchText === currentSearch){
// abort search if query wasn't different
return;
}
// clear results immediately (don't show expired results)
// NOTE: this can cause "flicker" as results are removed / re added
results.remove({});
if (searchText === ""){
return;
}
searching.set(true);
performSearch(searchText)
};
var performSearch = _.debounce(function(searchText){
currentSearch = searchText;
Meteor.apply('mySearchMethod', [searchText], {wait: false}, function(err, res){
if (err){
console.error(err);
}
if (currentSearrch !== searchText){
// query changed, results aren't relevant
return;
}
for (var i = 0; i < res.length; i++){
results.insert(res[i]);
}
searching.set(false);
})
}, 300);
Template.myTemplate.events({
'input #mySearchBox': function(e){
search($(e.currentTarget).val());
}
});
Template.myTemplate.heplers({
'searchResults': function(){
return results.find();
},
'showSpinner': function(){
return searching.get();
}
})
if (Meteor.isServer){
Meteor.methods({
'mySearchMethod': function(searchText){
check(searchText, String);
this.unblock();
var searchExp = new RegExp(RexExp.escape(searchText), 'i');
return myCollection.find({myField: searchExp}).fetch();
}
});
}
I am using sockets with mongodb, for a user who is trying to create a new name, I need to check all the models in the database to see if it exists.
I am doing it all wrong, basically I am trying to do something like this.
var allUsers = [];
models.Message.find({}, function(err, data) {
for(var i=0; i < data.length; i++) {
allUsers.push(data[i].username);
}
});
console.log(allUsers)
I'm sitting here struggling even getting the allUsers out of the function, and I am thinking this is not even the best way to do this. With allUsers I was just going to check to see if the new username existed in the array.
So to futher extend what I am doing here is some socket.io code. I was going to run some validation like this if I could get the allUsers to work.
socket.on('new user', function (data, callback) {
if(data in allUsers) {
callback(false);
} else {
callback(true);
socket.userName = data;
socket.connected = true;
users[socket.userName] = socket;
io.sockets.emit('user name', {usernames: users[socket.userName].userName, connected: users[socket.userName].connected});
}
});
But without it working, this is no good. So my question is with what I have provided (socket.io, mongodb) how do I get all the models and validate if a new user which is passed in data exists in the database?
models.Message.find is async, the result of the async operation is only available when the async operation has finished.so console.log(allUsers) will always yield an empty array.
should be something like (pseudo js code):
socket.on('new user', function (data, callback) {
models.User.findOne({username:data.username},function(err,user){
if(err){/*deal with error here */}
else if(user){/*username already taken
respond with appropriate socket message here */
socket.emit('user name already taken',{somemessage});
}
else{/* user with username not found */
/*create new user into database then emit socket message */
var user = new models.User(data);
user.save(function(err,user){
socket.emit('user name',{somemessage});
})
}
});
});