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Python

Posted by Nick Scola
Nick Scola
3,563 Points

Any suggestions on how to favorite a post?

I'm currently scratching my head over here trying to figure out a way to allow a user to favorite / star another user's post. I would assume we would need to grab the post ID and set some sort of relationship in models.py

1 Answer

Charles Lee
Charles Lee
17,825 Points

One way to implement a favorites feature is to create a Favorite model which would contain the user_id and post_id as foreign keys. Everytime a user favorites a post, we can create an instance of Favorite. If there is one that already exists with that exact user_id and post_id, we can destroy that instance, thereby 'unfavoriting' it.

This way allows you to make the resource RESTful and simply creating and destroying for 'favoriting' and 'unfavoriting.'

Nick Scola
Nick Scola
3,563 Points

Thanks for your help! I was able to create this type of feature.

Charles Lee
Charles Lee
17,825 Points

No probs. Glad I could help. :D

Nick Scola
Nick Scola
3,563 Points

Hey Charles, how come I'm getting this typerror: TypeError: argument of type 'SelectQuery' is not iterable

{% if not post.id in current_user.favorite() %}

Charles Lee
Charles Lee
17,825 Points

Hey Nick,

A guess would be that current_user.favorite() is returning something that the in operator will not work with. The in operator needs an iterable object.

Could you show me an example of what current_user.favorite() returns?

Nick Scola
Nick Scola
3,563 Points

Thanks for the response. I'm actually confused on why favorite() is not iterable but following() is:

    def following(self):
        # the users that we are following.
        return (
            User.select().join(
                Relationship, on = Relationship.to_user
            ).where(
                Relationship.from_user == self
            )
        )

    def favorite(self):
        # the posts we favorite
        return (
            User.select().join(
                Favorite, on = Favorite.to_user_post
            ).where(
                Favorite.from_user_fav == self
            )
        )

class Favorite(Model):
    from_user_fav = ForeignKeyField(User, related_name = 'relationships_from')
    to_user_fav = ForeignKeyField(User, related_name = 'relationships_to')
    to_user_post = ForeignKeyField(Post)

    class Meta:
        database = DATABASE
        indexes = (
            (('from_user_fav', 'to_user_fav', 'to_user_post'), True)
        )
Charles Lee
Charles Lee
17,825 Points

Well, I'm not entirely sure what's going on.

Maybe it's erroring out on an empty SelectQuery? Try out the exist() method. https://docs.djangoproject.com/en/1.8/ref/models/querysets/#django.db.models.query.QuerySet.exists

This also may be a related problem: http://stackoverflow.com/questions/6704749/relatedmanager-object-is-not-iterable-django

Nick Scola
Nick Scola
3,563 Points

Also here's what returns when I call {{ current_user.favorite() }}

<class 'models.User'> SELECT "t1"."id", "t1"."username", "t1"."email", "t1"."password", "t1"."joined_at", "t1"."is_admin" FROM "user" AS t1 INNER JOIN "favorite" AS t2 ON ("t3"."id" = "t2"."to_user_post_id") WHERE ("t2"."from_user_fav_id" = ?) ORDER BY "t1"."joined_at" DESC [1]