insert reblogged articles in the right place in blog.articles array ordered by created_at

Question

EDIT: Actually I just decided against my way of reblogging and instead decided to implement it by copying and making a whole new record from the article and then add a reblogged: true column to it. A bit cleaner in logic in my opinion and it avoids all the problems listed below.

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In a blog app I've implemented the possibility of reblogging an article of someone else's blog through a join reblog model with two foreign keys.

In my blogs show action I am then adding blog.articles with blog.reblogged_articles to one single array of articles. I then sort this array by the created_at attribute of each element.

However, for the reblogged articles, I'd rather like to use the created_at attribute of their reblog join model, so that a reblogged article will initially appear on the top of the blog. A reblogged article should always get its position in the blog as if it was created by the owner of the blog. But currently, a reblogged article might appear on the bottom of the blog, if the article was created 3 years ago.

I probably need to modify the created_at attributes of my reblogged_articles array before I put the two arrays together. But how do I do that?

Edit: Just an example to clarify:

Blog id 1:
Article id 1, created_at: A year ago.
Article id 2, created_at: A month ago.
Article id 3, created_at: A week ago.
Article id 4, created_at: A day ago.

Blog id 2:
Article id 5, created_at: A day ago.
Article id 6, created_at: An hour ago.
Article id 7, created_at: 30 minutes ago.
Article id 8, created_at: About 10 minutes ago.

Now, Blog 2 reblogs Article 1 of Blog 1. I want this article to be displayed on the top of Blog 2, as if it has been created just now. However, since that article in fact was created a year ago, it will be displayed on the bottom of Blog 2. How can I get around this?

What's the smartest approach to bring reblogged articles in their "correct" position based upon the created_at of the join model Reblog instead of the created_at of the article itself?

Answer 1

The easiest solution is probably just adding a last_activity_date column to your article model. Whenever an article is reblogged, update the corresponding article's last_activity_date. Then, when you're getting articles, Article.order(:last_activity_date => 'DESC')

EDIT: based on your clarifications -

# Merge arrays of article objects
all_articles = current_blog_articles | reblogged_articles 
all_articles.sort_by! {|x| -x.created_at } # Sort by created_at descending