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https://www.linkedin.com/in/mehreentahir93/

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INTEGRATING GRAPHQL �WITH � RUBY ON RAILS

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WEBINAR ROADMAP

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  • What Is GraphQL�
  • Typical REST Application

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  • REST Potential Drawback

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  • Graphql Application�
  • Graphql Operations�
  • Proof Of Concept Application

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WHAT IS HYPE ABOUT

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WHY & HOW IT CAME INTO EXISTENCE

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ARCHITECTURE

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UNDER FETCHING

SITUATIONS

OVER FETCHING

Need To Display Single Author With All Details

Need To List All Author Names

NOT ENOUGH DATA PER REQUEST�(Doesn’t fetch chapter details)

EXTRA DATA PER REQUEST�(Fetches un necessary book details)

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ARCHITECTURE

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QUERIES & MUTATIONS

QUERIES� mechanism for reading data

MUTATIONS� mechanism for creating/updating data

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Today’s proof of concept will be on a basic example, in which author can have many books and each book can have multiple chapters.

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  • Create rails project
    • rails new graphql_rubyconf --skip-test�
  • Generate models
    • rails g model Author email:string name:string
    • rails g model Book name:string description:text author:belongs_to
    • rails g model Chapter name:string short_description:text book:belongs_to�
  • Migrate DB
    • rake db:migrate�
  • Add missing associations in author and books models
    • author#has_many :books
    • book#has_many :chapters�
  • Datalayer is now all set!

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CREATING PROJECT SKELETON

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  • Add faker gem
    • gem “faker” (https://github.com/faker-ruby/faker)
    • bundle install�
  • Populate seed file�

2.times do

author = Author.create(name: Faker::Name.name, email: Faker::Internet.email)

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3.times do

book = author.books.create(name: Faker::Lorem.sentence(word_count:2), description: Faker::Lorem.paragraph(sentence_count:2))

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2.times do

book.chapters.create(name: Faker::Lorem.sentence(word_count: 2), short_description: Faker::Lorem.paragraph(sentence_count: 2))

end

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end

end�

  • Verify data in console

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SEEDING DATA FOR QUERYING

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  • Install graphql

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  • Run graphql install
    • rails generate graphql:install�
  • Check the graphql generator section added into rails generators
    • rails generate �
  • Schema file analysis�
  • Everything is ready for building some basic queries and we can boot our servers BUT visualization is not good yet.

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GRAPHQL INSTALLATION & OBJECT GENERATIONS

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  • Install graphiql-rails

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  • Following the guide, update the route file

� if Rails.env.development?

mount GraphiQL::Rails::Engine, at: "/graphql", graphql_path: "graphql#execute"

end�

  • Boot the server at http://localhost:3000/graphql (this is the single point of interaction)�
  • Try the default query

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ADDING BETTER VISUALIZATION

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GRAPHQL QUERIES

Queries are used to read data

Terminology: ��field

object

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  • Query to fetch all authors, which return all authors with name,id and book_count.�
  • Create GraphQL objects
    • rails g graphql:object author

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  • Add fields into author type
    • name
    • id
    • book_count�
  • Include these queries into base QueryType
    • add authors field which returns array of author type
    • define the corresponding rails method�
  • Execute the basic query

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(1) QUERY LIST OF AUTHORS WITH BASIC INFORMATION

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  • Extend the query to fetch relational data for instance books list for the authors.�
  • Create GraphQL objects
    • rails g graphql:object book

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  • Add fields into book type
    • name
    • id
    • description

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  • Add the association field for books into author type.

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  • Execute the basic relational query

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(2) QUERY LIST OF AUTHORS WITH BOOKS

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  • Extend book to fetch chapters and author details�
  • Create GraphQL objects
    • rails g graphql:object chapter�
  • Add fields into chapter type
    • name
    • short_description
    • id
    • author_name

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  • Add the association of chapters into book type.�
  • Execute the query

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(3) QUERY LIST OF AUTHORS WITH BOOKS AND ITS CHAPTERS

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  • Execute the query�

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QUERY

FETCH LIST OF AUTHORS

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  • Define single author query in base query for graphql�
    • add author field which returns author type
    • block which takes the required ‘id’ argument
    • define the corresponding rails method

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QUERY FOR SINGLE AUTHOR

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  • Execute the query��

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QUERY

FETCH SINGLE AUTHOR

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GRAPHQL MUTATIONS

Mutations are used for Creating and updating data

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Terminology:��arguments

fields

resolve ��

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  • Create new mutation�
    • Inside mutations folder, create a new file named as create_author.rb

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    • Create a class and inherit from base mutation�Mutations::CreateAuthor < Mutations::BaseMutation

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    • Add description to this mutation

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    • Add arguments which mutation needs for its creation
      • name
      • email

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    • Add fields which mutation will return upon creation, in our case it will be
      • author
      • errors�
    • Add the resolve method
      • Perform the active record part in it and create it
      • Return hash with author and error keys�
  • Add the mutation type as field in base mutation type, with referring the mutation we created
    • field :create_author, mutation: Mutations::CreateAuthor�

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CREATE AUTHOR MUTATION

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  • Execute the mutation�

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CREATE AUTHOR MUTATION

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  • Create new mutation�
    • Inside mutations folder, create a new file named as update_author.rb

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    • Create a class and inherit from base mutation�Mutations::UpdateAuthor < Mutations::BaseMutation

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    • Add description to this mutation

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    • Add arguments which mutation needs for its creation
      • name
      • ID

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    • Add fields which mutation will return upon creation, in our case it will be
      • author
      • errors�
    • Add the resolve method
      • Perform the active record part in it and update it
      • Return hash with author and error keys�
  • Add the mutation type as field in base mutation type, with referring the mutation we created
    • field :update_author, mutation: Mutations::UpdateAuthor

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UPDATE AUTHOR MUTATION

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  • Execute the mutation���

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UPDATE AUTHOR MUTATION

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RESOURCES

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THANK YOU