Sails.js Set model value with value from Callback

Question

i need to provide something like an association in my Model. So I have a Model called Posts with an userid and want to get the username from this username and display it.

So my ForumPosts.js Model looks like the following:

module.exports = {

  schema: true,

  attributes: {

    content: {
        type: 'text',
        required: true
    },

    forumTopicId: {
        type: 'text',
        required: true
    },

    userId: {
      type: 'integer',
      required: true
    },

    getUsername: function(){
      User.findOne(this.userId, function foundUser(err, user) {
        var username =  user.username;
      });
      console.log(username);
      return username;
    }
  }

};

I know that this return will not work because it is asynchronus... But how can i display it in my view? At the Moment i retrive the value with:

<%= forumPost.getUsername() %>

And for sure get an undefined return...

So the question is: How can I return this value - or is there a better solution than an instanced Model?

Thanks in advance!

http://stackoverflow.com/questions/17683015/how-to-perform-sql-joins-in-sails-js-waterline — bredikhin, Jan 06 '14 at 16:04
Model.query(, , callback); is not working, dont know why it cant find the Model anyhow... But there must be a way to overgive the return via the callback... — Lugaru, Jan 06 '14 at 21:38
`Model.query(, , callback);` is for SQL DBs only. Which adapter are you using? — bredikhin, Jan 06 '14 at 21:50

score 5 · Accepted Answer · answered Jan 06 '14 at 22:28

Off the top of my head, you can just load associated user asynchronously before rendering:

loadUser: function(done){
  var that = this;

  User.findOne(this.userId, function foundUser(err, user) {
    if ((err)||(!user))
        return done(err);

    that.user = user;

    done(null);
  });
}

then in your controller action:

module.exports = {
  index: function(req, res) {
    // Something yours…

    forumPost.loadUser(function(err) {
      if (err)
        return res.send(err, 500);

      return res.view({forumPost: forumPost});
    });
  }
}

and in your view:

<%= forumPost.user.username %>

This is kind of a quick and dirty way. For a more solid and long-term solution (which is still in development so far) you can check out the alpha of Sails v0.10.0 with the Associations API.

score 3 · Answer 2 · answered Jan 08 '14 at 07:29

So this particularly case of associations between your models. So here you have a User model and ForumPost model and you need the user object in place of your user_id as user_id works as a relationship mapping field to your User model.

So if your are using sails V0.9.8 or below you need to handle this logic in your controller where ever you want to access User model attributes in your view.

In your controller write your logic as:

model.export = {
      //your getForumPosts method
      getForumPosts : function(req,res){
         var filters = {};     

         forumPost.find(filters).done(function(err,posts){
             if(err) return res.send(500,err);
             // Considering only one post obj
             posts = posts[0];
             postByUser(posts.user_id,function(obj){
                 if(obj.status)
                 {
                    posts.user = obj.msg;
                    delete posts.user_id;
                    res.view({post:posts});
                 }
                 else
                 {
                    res.send(500,obj.msg);
                 }
             });

         }
      }

    }

         function postByUser(user_id,cb){
            User.findOne(user_id).done(function(err,user){
                 if(err) return cb({status:false, msg:err});

                 if(user){
                   cb({status:true, msg:user});
                 }
            }
         }

and then you can access your post object in your view.

Or else you can keep watch (at GitHub) on next version of sails as they have announced associations in V0.10 n it is in beta testing phase as if now.

Hey this solves it nearly. But i have the Problem, that i have multiple Forumposts, not just one. In your example you would only get the user from one Post and Display this one, but i have multiple Posts underneath each otehr — Lugaru, Jan 10 '14 at 08:56

Sails.js Set model value with value from Callback

2 Answers2