What is the best way to fetch relation data in REST API?

I'm learning to design a REST API and am having trouble retrieving data in relations, which way should I use, and I'd like to know how big companies handle this kind of thing.

For example I'm designing a blog site.

Say I have the following 2 models:

model authors {
    id
    name
}


model posts {
    id
    title
    author_id
}

One author can have multiple posts, or one post can only have one author.

Frontend requirement: on the post/blog index page I want to display the post title and author name, more or less like this:

---------------------

[posts.title]

[authors.name]

---------------------

---------------------

[posts.title]

[authors.name]

---------------------

etc.

As I understand there are two methods:

Method 1:

GET /posts - fetch posts without author. let's say it returns 10 posts

I then iterate for each post to retrieve author data: GET /posts/{posts.id}/author

The result: I made 11 HTTP requests.

Method 2:

GET /posts - fetch posts back with author.

The result: I only made 1 HTTP request.

So far I have used method 2, regardless of whether the frontend requires an author or not, but I feel this is not the right method. Which method should I use? I feel method 1 makes more sense but I'm still unsure. Method 1 I think is more often used in applications with microservice architecture.

I really appreciate any answer, thanks in advance.

> I'm learning to design a REST API and am having trouble retrieving
> data in relations, which way should I use, and I'd like to know how
> big companies handle this kind of thing.

There are various alternatives available when it comes to creating a REST API that works with relational data. But the two most popular approaches are:

1. METHOD 1: Multiple requests for data retrieval

With this approach, you make separate requests to fetch related data. For instance, you may send one request to get all the posts and another to get each post's author information. This method is often referred to as "lazy loading," as the related data is only loaded when it is needed.

2. METHOD 2: Fetching Data in a Single Request

By using this method, you can get all the data you require, including related data, with a single request. For instance, you could send a single request to retrieve all the posts and the writers associated with them. Due to the fact that all relevant data is loaded, this strategy is frequently referred to as "eager loading.

The choice of which approach to adopt will rely on a number of variables, including the size of the data, the intricacy of the relationships, and the performance needs of your application. Both methods offer benefits and drawbacks.

> For example I'm designing a blog site.
> ...

You can use one of the two techniques in your particular situation, where you have a blog site with two models, authors and posts, and you want to display the post title and author name on the post/blog index page.

The data for each post would need to be fetched twice using Method 1, which can take longer if there are many posts. However, this approach can be helpful if you want to reduce the time it takes for the page to load initially. You can do this by retrieving only the posts' data initially, and then the author's data as needed when a user interacts with the page.

In contrast, method 2 would involve sending a single request to retrieve all the data at once. If you only have a few posts, this may go more quickly; but, if you have many posts and authors, it may take longer. However, if you want to minimise requests and decrease network latency, this approach may be helpful.

That's it! Generally speaking, using both strategies would be the best course of action, depending on your unique needs. For instance, you could use method 2 to retrieve the data for the first few posts before switching to method 1 as necessary to retrieve the data for the remaining articles.