Need help validating query parameters - ruby-on-rails

Question

I have multiple methods within my controller that takes in query parameters. How can I validate that I am being passed in valid parameters? For example, for the index method, how can I make sure that I am getting an array of authorIds.
def index
author_ids_array = params[:authorIds].to_s.split(',')
posts = Post
.get_posts_by_user_id(author_ids_array)
.order(sort_column => sort_direction)
if posts
render json: { posts: posts }, status: :ok
else
render json: {error: posts.errors}, status: :unprocessable_entity
end
end
Or in this update method. How can I validate that I am getting a valid postId
def update
post = current_user.posts.find_by(id: params[:id])
if post.update!(post_params)
post_hash = post.as_json
post_hash.merge!(authorIds: params[:authorIds])
render json: {post: post_hash}, status: :ok
else
render json: {error: post.errors}, status: :unprocessable_entity
end
end
Update:
Post Model:
class Post < ApplicationRecord
# Associations
has_many :user_posts
has_many :users, through: :user_posts, dependent: :destroy
# Validations
validates :text, presence: true, length: { minimum: 3 }
validates :popularity, inclusion: { in: 0.0..1.0 }
def tags
if super
super.split(",")
end
end
def tags=(value)
if value.kind_of? Array
super value.join(",")
else
super value
end
end
def self.get_posts_by_user_id(user_id)
Post.joins(:user_posts).where(user_posts: { user_id: user_id })
end
end
User Model:
class User < ApplicationRecord
has_secure_password
# Associations
has_many :user_posts
has_many :posts, through: :user_posts, dependent: :destroy
# Validations
validates :username, :password, presence: true
validates :password, length: { minimum: 6 }
validates :username, uniqueness: true
end
User_post Model:
class UserPost < ApplicationRecord
belongs_to :user
belongs_to :post
end

Answer 1

You can use specific render like below user this in any method like
def index
return render body: params.inspect
.
.
end
user below code
return render body: params.inspect
so when you use index it will give you params which is passing
OR you can user below code in your application.html.erb above <%= yield%>
<%= debug(params) if Rails.env.development? %>

Answer 2

After your clarifications, your question remains unclear to me and it is difficult to guess what you're doing. But I understood that you want to ensure that params[:authorIds] or anything else is an array.
You can see if a given variable is an array the following way:
a = ["1","2"]
if a.is_a?(Array)
puts "is an array"
end
With params: params[:authorIds].is_a?(Array)
You can use byebug (before Rails 7) or debugger (for Rails 7) to inspect what a param is. As an example:
(ruby#whatever: cluster worker 1: 42779 [MyApp]#42793) params[:ids].class
Array