Introduced # 9 serializer to build bulletin board API with authentication authorization in Rails 6

← Building a bulletin board API with certification authorization in Rails 6 # 8 seed implementation

Introduction of ActiveModelSerializer

By including serializer, you can easily format the data returned by json.

Gemfile

...

+ # serializer
+ gem "active_model_serializers"

$ bundle

Editing config files and serializer

Once installed, create a post model serializer and an ActiveModelSerializer configuration file.

$ rails g serializer post
$ touch config/initializers/active_model_serializer.rb

app/serializers/post_serializer.rb

# frozen_string_literal: true

#
# post serializer
#
class PostSerializer < ActiveModel::Serializer
  attributes :id
end

config/initializers/active_model_serializer.rb

# frozen_string_literal: true

ActiveModelSerializers.config.adapter = :json

app/controllers/v1/posts_controller.rb

     def index
       posts = Post.order(created_at: :desc).limit(20)
-      render json: { posts: posts }
+      render json: posts
     end
 
     def show
-      render json: { post: @post }
+      render json: @post
     end
 
     def create
       post = Post.new(post_params)
       if post.save
-        render json: { post: post }
+        render json: post
       else
         render json: { errors: post.errors }
       end
@@ -27,7 +27,7 @@ module V1
 
     def update
       if @post.update(post_params)
-        render json: { post: @post }
+        render json: @post
       else
         render json: { errors: @post.errors }
       end
@@ -35,7 +35,7 @@ module V1
 
     def destroy
       @post.destroy
-      render json: { post: @post }
+      render json: @post
     end

Once you've done this, stop rails s and restart.

Check with curl

$ curl localhost:8080/v1/posts 
{"posts":[{"id":20},{"id":19},{"id":18},{"id":17},{"id":16},{"id":15},{"id":14},{"id":13},{"id":12},{"id":11},{"id":10},{"id":9},{"id":8},{"id":7},{"id":6},{"id":5},{"id":4},{"id":3},{"id":2},{"id":1}]}
$ curl localhost:8080/v1/posts/1
{"post":{"id":1}}

I was able to get a list of ids because only ids are used in serializer. Now let's add subject and body.

app/serializers/post_serializer.rb

 # frozen_string_literal: true

 #
 # post serializer
 #
 class PostSerializer < ActiveModel::Serializer
-  attributes :id
+  attributes :id, :subject, :body  
 end

$ curl localhost:8080/v1/posts
{"posts":[{"id":20,"subject":"Useless","body":"The bee's cuckoo. Violent blood grudge. The hidden ruins."},...
curl localhost:8080/v1/posts/1
{"post":{"id":1,"subject":"hello","body":"Captain General Police Officer. Meishibokin Katamichi. Traditional Tokugawa super ~.

It seems to be working normally. Let's also run rubocop and rspec and commit if there is no problem.

Continued

→ Introduce # 10 devise_token_auth to build bulletin board API with authentication authorization in Rails 6 [To the serial table of contents]