Ruby_Kaigi_slides.pdf

I will start with some GraphQL basics, then dig into process of metaprogramming a GraphQL layer from a demo ruby server. I will explain the benefits of using this design pattern and how it improves developer experience.

Transcript

1. GraphQL Migration:
   A Use Case for Metaprogramming?
   RubyKaigi 2019
   shawneegao@squareup.com
   @gao_shawnee
   

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2. About Me
   

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5. wagashi wagashi wagashi
   Lake Ashi ft. Mt. Fuji (a.k.a. shy Fuji-san as he’s often covered by fog).
   

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7. Japan Loves Cash
   

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14. Inventory Price per Unit Restock Date Units Sold
    Cuban Links (Sets) $14,000 3/10/2014 23
    Diamond Custom Cuts $200,000 3/10/2014 43
    Classic Open Face $230,000 3/10/2014 12
    Solid Classics $9,000 3/10/2014 11
    Promo Duration Promo Details # Promos used
    Breezey Promo 3/21/2014 - Forever xx off Loyalty 22
    Full Set Discount 3/21/2014 - 4/12/2014 xx% off full set 12
    Deposits
    Pending: $XX
    Devices: XX
    # Employees: XX Gift Cards
    Has Loans
    Subscriptions
    # Payments
    Received
    Marketing Plans
    Appointments
    Chargebacks
    And So Much
    More …
    # Refunds
    Grillz by Nelly en-US St. Louis, MO
    Freeze Deactivate Audit
    Actions: Resolve Unfreeze
    Payments Graph
    

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15. Locations
    Promo
    Appointments
    Seller Service
    Inventory
    Chargebacks
    Capital
    Employees
    Deposits
    Marketing
    Hardware
    Dashboard’s Write Paths
    Payments
    Subscriptions
    

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16. 273,249 lines of Ruby
    

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17. 22,337 lines of YAML
    

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18. Over 200 Controllers
    

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19. Talking to over 150
    Services
    

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21. request.open(
    'GET',
    https://squareup.resources.com/payment/4567
    )
    Response: ???????
    

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22. {
    “data” : [
    payment:
    {
    “id”: “4567”,
    “amount”: “300”,
    “merchant”: “1234”,
    “card: “7890”
    }
    ]
    }
    

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23. Underfetched!
    Date Amount Status Merchant Method
    3/10/19 $900 Success Grillz by Nelly Debit
    {
    “data” : [
    payment:
    {
    “id”: “4567”,
    “amount”: “300”,
    “merchant”: “1234”,
    “card: “7890”
    }
    ]
    }
    

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24. graphql demo
    

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25. Different Resources
    
    Relational
    Highly Diverse
    

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26. Road Map
    • Existing Model Architecture
    • Write a GraphQL Ruby API
    • Add metaprogramming to our API
    • Add/Change Business Object
    • Testing
    

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27. REST
    ~150 Specialized Services
    

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28. ~150 Specialized Services
    REST Backend REST Frontend
    Agents
    

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29. ~150 Specialized Services
    REST Backend GQL Frontend
    Agents
    

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30. ~150 Specialized Services
    REST Backend GQL Frontend
    Agents
    Target
    

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31. ~150 Specialized Services
    REST Backend GQL Frontend
    Agents
    Target
    

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32. Target
    ~150 Specialized Services
    REST Backend GQL Frontend
    Agents
    

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33. Targets
    

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34. 1 class TargetBase
    2 include TargetMethods
    3 extend ModuleHelper
    4
    5 def self._fetch_target_data(_token)
    6 raise NotImplementedError
    7 end
    8
    9 def self.lookup(token)
    10 target_data = _fetch_target_data(token)
    11 new(target_data: target_data)
    12 end
    13
    14 def id
    15 target_data.id
    16 end
    17 end
    

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35. 1 class TargetBase
    2 include TargetMethods
    3 extend ModuleHelper
    4
    5 def self._fetch_target_data(_id)
    6 raise NotImplementedError
    7 end
    8
    9 def self.lookup(id)
    10 target_data = _fetch_target_data(id)
    11 new(target_data: target_data)
    12 end
    13
    14 def id
    15 target_data.id
    16 end
    17 end
    

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36. 1 class TargetBase
    2 include TargetMethods
    3 extend ModuleHelper
    4
    5 def self._fetch_target_data(_id)
    6 raise NotImplementedError
    7 end
    8
    9 def self.lookup(id)
    10 target_data = _fetch_target_data(id)
    11 new(target_data: target_data)
    12 end
    13
    14 def id
    15 target_data.id
    16 end
    17 end
    

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37. 1 class TargetBase
    2 include TargetMethods
    3 extend ModuleHelper
    4
    5 def self._fetch_target_data(_id)
    6 raise NotImplementedError
    7 end
    8
    9 def self.lookup(id)
    10 target_data = _fetch_target_data(id)
    11 new(target_data: target_data)
    12 end
    13
    14 def id
    15 target_data.id
    16 end
    17 end
    

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38. Payment
    - id
    - amount
    - merchant_id
    Merchant
    - id
    - store_name
    Is associated through merchant_id
    Today’s Data Model
    

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39. app/models/merchant.rb
    4 class Merchant < TargetBase
    5 stub_target_data(
    6 resource: 'merchant',
    7 id: 4567,
    8 response_body: {
    9 id: 4567,
    10 store_name: 'Grillz by Nelly'
    11 }
    12 )
    13
    14 def self._fetch_target_data(merchant_id)
    15 target_data =
    16 MerchantClient.get_by_id(merchant_id)
    18
    19 OpenStruct.new(target_data)
    20 end
    21
    22 def store_name
    23 target_data.store_name
    24 end
    25 end
    

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40. 4 class Merchant < TargetBase
    5 stub_target_data(
    6 resource: 'merchant',
    7 id: 4567,
    8 response_body: {
    9 id: 4567,
    10 store_name: 'Grillz by Nelly'
    11 }
    12 )
    13
    14 def self._fetch_target_data(merchant_id)
    15 target_data =
    16 MerchantClient.get_by_id(merchant_id)
    18
    19 OpenStruct.new(target_data)
    20 end
    21
    22 def store_name
    23 target_data.store_name
    24 end
    25 end
    

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41. 4 class Merchant < TargetBase
    5 stub_target_data(
    6 resource: 'merchant',
    7 id: 4567,
    8 response_body: {
    9 id: 4567,
    10 store_name: 'Grillz by Nelly'
    11 }
    12 )
    13
    14 def self._fetch_target_data(merchant_id)
    15 target_data =
    16 MerchantClient.get_by_id(merchant_id)
    18
    19 OpenStruct.new(target_data)
    20 end
    21
    22 def store_name
    23 target_data.store_name
    24 end
    25 end
    

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42. 4 class Merchant < TargetBase
    5 stub_target_data(
    6 resource: 'merchant',
    7 id: 4567,
    8 response_body: {
    9 id: 4567,
    10 store_name: 'Grillz by Nelly'
    11 }
    12 )
    13
    14 def self._fetch_target_data(merchant_id)
    15 target_data =
    16 MerchantClient.get_by_id(merchant_id)
    17 .parsed_response
    18
    19 OpenStruct.new(target_data)
    20 end
    21
    22 def store_name
    23 target_data.store_name
    24 end
    25 end
    

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43. 4 class Payment < TargetBase
    5 stub_target_data(
    6 resource: 'payment',
    7 id: 1234,
    8 response_body: {
    9 id: 1234,
    10 amount: 100,
    11 merchant_id: 4567
    12 }
    13 )
    14
    15 def self._fetch_target_data(payment_id)
    17 target_data =
    18 PaymentClient.get_by_id(payment_id)
    20
    21 OpenStruct.new(target_data)
    22 end
    23
    24 def amount
    25 target_data.amount
    26 end
    29
    30 def merchant_id
    31 target_data.merchant_id
    32 end
    33
    34 def merchant
    35 @merchant ||= Merchant.lookup(merchant_id)
    37 end
    38 end
    

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44. 4 class Payment < TargetBase
    5 stub_target_data(
    6 resource: 'payment',
    7 id: 1234,
    8 response_body: {
    9 id: 1234,
    10 amount: 100,
    11 merchant_id: 4567
    12 }
    13 )
    14
    15 def self._fetch_target_data(payment_id)
    17 target_data =
    18 PaymentClient.get_by_id(payment_id)
    20
    21 OpenStruct.new(target_data)
    22 end
    23
    24 def amount
    25 target_data.amount
    26 end
    29
    30 def merchant_id
    31 target_data.merchant_id
    32 end
    33
    34 def merchant
    35 @merchant ||= Merchant.lookup(merchant_id)
    37 end
    38 end
    

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45. 4 class Payment < TargetBase
    5 stub_target_data(
    6 resource: 'payment',
    7 id: 1234,
    8 response_body: {
    9 id: 1234,
    10 amount: 100,
    11 merchant_id: 4567
    12 }
    13 )
    14
    15 def self._fetch_target_data(payment_id)
    17 target_data =
    18 PaymentClient.get_by_id(payment_id)
    20
    21 OpenStruct.new(target_data)
    22 end
    23
    24 def amount
    25 target_data.amount
    26 end
    29
    30 def merchant_id
    31 target_data.merchant_id
    32 end
    33
    34 def merchant
    35 @merchant ||= Merchant.lookup(merchant_id)
    37 end
    38 end
    

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46. 4 class Payment < TargetBase
    5 stub_target_data(
    6 resource: 'payment',
    7 id: 1234,
    8 response_body: {
    9 id: 1234,
    10 amount: 100,
    11 merchant_id: 4567
    12 }
    13 )
    14
    15 def self._fetch_target_data(payment_id)
    17 target_data =
    18 PaymentClient.get_by_id(payment_id)
    20
    21 OpenStruct.new(target_data)
    22 end
    23
    24 def amount
    25 target_data.amount
    26 end
    29
    30 def merchant_id
    31 target_data.merchant_id
    32 end
    33
    34 def merchant
    35 @merchant ||= Merchant.lookup(merchant_id)
    37 end
    38 end
    

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47. 4 class Payment < TargetBase
    5 stub_target_data(
    6 resource: 'payment',
    7 id: 1234,
    8 response_body: {
    9 id: 1234,
    10 amount: 100,
    11 merchant_id: 4567
    12 }
    13 )
    14
    15 def self._fetch_target_data(payment_id)
    17 target_data =
    18 PaymentClient.get_by_id(payment_id)
    20
    21 OpenStruct.new(target_data)
    22 end
    23
    24 def amount
    25 target_data.amount
    26 end
    29
    30 def merchant_id
    31 target_data.merchant_id
    32 end
    33
    34 def merchant
    35 @merchant ||= Merchant.lookup(merchant_id)
    37 end
    38 end
    

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48. => Payment
    Payment
    p = Payment.lookup(1234)
    => #
    p.amount
    => 100
    p.merchant
    => #
    p.merchant.store_name
    => “Grillz by Nelly”
    Merchant
    => Merchant
    m = Merchant.lookup(4567)
    m.store_name
    => “Grillz by Nelly”
    => #
    

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49. Let’s Create a GraphQL API:
    GQL Ruby Query Flow
    

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50. Payment
    - id
    - amount
    - merchant_id
    Merchant
    - id
    - store_name
    Is associated through merchant_id
    Today’s Data Model
    

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51. Graphql Controller
    DemoSchema
    Mutation Type
    Query Type
    Payment Type Merchant Type
    id amount merchant id store_name
    Some Mutation
    Merchant Type
    id store_name
    

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52. Graphql Controller
    DemoSchema
    Mutation Type
    Query Type
    Payment Type Merchant Type
    id amount merchant id store_name
    Some Mutation
    Merchant Type
    id store_name
    Bank Accounts Controller
    Hardware Controller
    

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53. Graphql Controller
    DemoSchema
    Mutation Type
    Query Type
    Payment Type Merchant Type
    id amount merchant id store_name
    Some Mutation
    Merchant Type
    id store_name
    

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54. query($paymentId: ID!){
    payment(id: $paymentId) {
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    

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55. 1 class GraphqlController < ApplicationController
    2 def execute
    3 .....
    4 result =
    5 DemoSchema.execute(
    6 query,
    7 variables: variables,
    9 ...
    10 )
    11 render json: result
    12 rescue => e
    13 raise e
    14 end
    query($paymentId: ID!){
    payment(id: $paymentId) {
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    app/controllers/graphql_controller.rb
    

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56. 1 class GraphqlController < ApplicationController
    2 def execute
    3 .....
    4 result =
    5 DemoSchema.execute(
    6 query,
    7 variables: variables,
    9 ...
    10 )
    11 render json: result
    12 rescue => e
    13 raise e
    14 end
    query($paymentId: ID!){
    payment(id: $paymentId) {
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    app/controllers/graphql_controller.rb
    

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57. 1 class GraphqlController < ApplicationController
    2 def execute
    3 .....
    4 result =
    5 DemoSchema.execute(
    6 query,
    7 variables: variables,
    9 ...
    10 )
    11 render json: result
    12 rescue => e
    13 raise e
    14 end
    query($paymentId: ID!){
    payment(id: $paymentId) {
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    app/controllers/graphql_controller.rb
    

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58. 1 class GraphqlController < ApplicationController
    2 def execute
    3 .....
    4 result =
    5 DemoSchema.execute(
    6 query,
    7 variables: variables,
    9 ...
    10 )
    11 render json: result
    12 rescue => e
    13 raise e
    14 end
    query($paymentId: ID!){
    payment(id: $paymentId) {
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    app/controllers/graphql_controller.rb
    

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59. query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    1 class DemoSchema < GraphQL::Schema
    2 query(Types::QueryType)
    3 query(Types::MutationType)
    4 end
    app/graphql/demo_schema.rb
    

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60. query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    1 class DemoSchema < GraphQL::Schema
    2 query(Types::QueryType)
    3 query(Types::MutationType)
    4 end
    app/graphql/demo_schema.rb
    

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61. query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    1 module Types
    2 class QueryType < Types::BaseObject
    3 field :payment, Types::PaymentType, null: false do
    4 argument :id, ID, required: true
    5 end
    6
    7 field :merchant, Types::MerchantType, null: false do
    8 argument :id, ID, required: true
    9 end
    10
    11 def payment(params)
    12 Payment.lookup(params[:id])
    13 end
    14
    15 def merchant(params)
    16 Merchant.lookup(params[:id])
    17 end
    18 end
    19 end
    20
    app/graphql/type/query_type.rb
    

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62. query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    1 module Types
    2 class QueryType < Types::BaseObject
    3 field :payment, Types::PaymentType, null: false do
    4 argument :id, ID, required: true
    5 end
    6
    7 field :merchant, Types::MerchantType, null: false do
    8 argument :id, ID, required: true
    9 end
    10
    11 def payment(params)
    12 Payment.lookup(params[:id])
    13 end
    14
    15 def merchant(params)
    16 Merchant.lookup(params[:id])
    17 end
    18 end
    19 end
    20
    app/graphql/type/query_type.rb
    

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63. payment(id: $paymentId)
    3 field :payment, Types::PaymentType, null: false do
    4 argument :id, ID, required: true
    5 end
    “paymentId”: 1234
    

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64. payment(id: $paymentId)
    3 field :payment, Types::PaymentType, null: false do
    4 argument :id, ID, required: true
    5 end
    “paymentId”: 1234
    

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65. query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    1 module Types
    2 class QueryType < Types::BaseObject
    3 field :payment, Types::PaymentType, null: false do
    4 argument :id, ID, required: true
    5 end
    6
    7 field :merchant, Types::MerchantType, null: false do
    8 argument :id, ID, required: true
    9 end
    10
    11 def payment(params)
    12 Payment.lookup(params[:id])
    13 end
    14
    15 def merchant(params)
    16 Merchant.lookup(params[:id])
    17 end
    18 end
    19 end
    20
    app/graphql/type/query_type.rb
    

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66. 1 class Types::PaymentType < Types::BaseObject
    2 field :id, ID, null: false
    3 field :amount, Int, null: false
    4 field :merchant, Types::MerchantType, null: false
    5 end
    app/graphql/type/payment_type.rb
    query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    

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67. query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    1 class Types::PaymentType < Types::BaseObject
    2 field :id, ID, null: false
    3 field :amount, Int, null: false
    4 field :merchant, Types::MerchantType, null: false
    5 end
    app/graphql/type/payment_type.rb
    

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68. payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    1 class Types::PaymentType < Types::BaseObject
    2 field :id, ID, null: false
    3 field :amount, Int, null: false
    4 field :merchant, Types::MerchantType, null: false
    5 end
    

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69. payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    1 class Types::PaymentType < Types::BaseObject
    2 field :id, ID, null: false
    3 field :amount, Int, null: false
    4 field :merchant, Types::MerchantType, null: false
    5 end
    

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70. query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    app/graphql/type/merchant_type.rb
    1 class Types::MerchantType < Types::BaseObject
    2 field :id, ID, null: false
    3 field :storeName, String, null: false
    4 end
    

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71. query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    app/graphql/type/merchant_type.rb
    1 class Types::MerchantType < Types::BaseObject
    2 field :id, ID, null: false
    3 field :storeName, String, null: false
    4 end
    

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72. merchant {
    id
    storeName
    }
    app/graphql/type/merchant_type.rb
    1 class Types::MerchantType < Types::BaseObject
    2 field :id, ID, null: false
    3 field :storeName, String, null: false
    4 end
    

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73. merchant {
    id
    storeName
    }
    app/graphql/type/merchant_type.rb
    1 class Types::MerchantType < Types::BaseObject
    2 field :id, ID, null: false
    3 field :storeName, String, null: false
    4 end
    

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74. query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    1 module Types
    2 class QueryType < Types::BaseObject
    3 field :payment, Types::PaymentType, null: false do
    4 argument :id, ID, required: true
    5 end
    6
    7 field :merchant, Types::MerchantType, null: false do
    8 argument :id, ID, required: true
    9 end
    10
    11 def payment(params)
    12 Payment.lookup(params[:id])
    13 end
    14
    15 def merchant(params)
    16 Merchant.lookup(params[:id])
    17 end
    18 end
    19 end
    20
    app/graphql/type/query_type.rb
    

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75. query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    1 module Types
    2 class QueryType < Types::BaseObject
    3 field :payment, Types::PaymentType, null: false d
    4 argument :id, ID, required: true
    5 end
    6
    7 field :merchant, Types::MerchantType, null: false do
    8 argument :id, ID, required: true
    9 end
    10
    11 def payment(params)
    12 Payment.lookup(params[:id])
    13 end
    14
    15 def merchant(params)
    16 Merchant.lookup(params[:id])
    17 end
    18 end
    19 end
    20
    app/graphql/type/query_type.rb
    

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76. query($paymentId: ID!){
    payment(id: $paymentId){
    id
    amount
    merchant {
    id
    storeName
    }
    }
    }
    variables{
    “paymentId”: 1234
    }
    1 module Types
    2 class QueryType < Types::BaseObject
    3 field :payment, Types::PaymentType, null: false d
    4 argument :id, ID, required: true
    5 end
    6
    7 field :merchant, Types::MerchantType, null: false do
    8 argument :id, ID, required: true
    9 end
    10
    11 def payment(params)
    12 Payment.lookup(params[:id])
    13 end
    14
    15 def merchant(params)
    16 Merchant.lookup(params[:id])
    17 end
    18 end
    19 end
    20
    app/graphql/type/query_type.rb
    

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77. Payment.lookup(1234)
    

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78. Payment.lookup(1234)
    {
    "data": {
    "payment": {
    "id": "1234",
    "amount": 100,
    "merchant": {
    "id": “4567",
    "storeName": “Grillz by Nelly”
    }
    }
    }
    }
    

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79. Is metaprogramming a
    good idea?
    

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80. 1. Flexible
    
    2. Reduce Boilerplate
    
    3. Improved Developer Experience
    Is metaprogramming a good
    idea?
    

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81. GraphQL Controller
    DemoSchema
    Types::QueryType
    Root Types
    Root Type Resolvers
    field :payment …
    field :merchant …
    def payment …
    def merchant …
    validates
    Types::PaymentType
    Types::MerchantType
    GQL Type Classes
    Payment
    Merchant
    Target Classes
    

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82. GraphQL Controller
    DemoSchema
    Types::QueryType
    Root Types
    Root Type Resolvers
    field :payment …
    field :merchant …
    def payment …
    def merchant …
    validates
    Types::PaymentType
    Types::MerchantType
    GQL Type Classes
    Payment
    Merchant
    Target Classes
    

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83. Types::QueryType
    Root Types
    Root Type Resolvers
    field :payment …
    field :merchant …
    def payment …
    def merchant …
    Types::PaymentType
    Types::MerchantType
    GQL Type Classes
    

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84. Types::QueryType
    Root Types
    Root Type Resolvers
    field :payment …
    field :merchant …
    def payment …
    def merchant …
    Types::PaymentType
    Types::MerchantType
    GQL Type Classes
    

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85. Types::PaymentType
    Types::MerchantType
    GQL Type Classes
    

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86. Priming:
    Target Class Annotations
    

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87. Payment
    - id
    - amount
    - merchant_id
    Merchant
    - id
    - store_name
    Is associated through merchant_id
    Today’s Data Model
    

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88. Payment
    - id
    - amount
    - merchant_id
    Merchant
    - id
    - store_name
    Is associated through merchant_id
    Today’s Data Model
    gql_field_annotations
    gql_field_annotations
    

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89. Payment.gql_field_annotations
    => {
    amount: {type: "Integer", null: false},
    id: {type: "Types::BaseObject::ID", null: false},
    merchant: {type: "Types::MerchantType", null: false}
    }
    

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90. Payment.gql_field_annotations
    => {
    amount: {type: "Integer", null: false},
    id: {type: "Types::BaseObject::ID", null: false},
    merchant: {type: "Types::MerchantType", null: false}
    }
    

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91. 4 class Payment < TargetBase
    33 def amount
    34 target_data.amount
    35 end
    36
    38 def token
    39 target_data.token
    40 end
    41
    42 def merchant_token
    43 target_data.merchant_token
    44 end
    45
    47 def merchant
    48 @merchant ||= Merchant.lookup(merchant_token)
    49 end
    50 end
    

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92. 4 class Payment < TargetBase
    5 mattr_accessor :gql_field_annotations do
    6 {}
    7 end
    9 . . .
    32 annotate_field "Integer", null: false, definition:
    33 def amount
    34 target_data.amount
    35 end
    36
    37 annotate_field "Types::BaseObject::ID", null: false, definition:
    38 def token
    39 target_data.token
    40 end
    41
    42 def merchant_id
    43 target_data.merchant_id
    44 end
    45
    46 annotate_field "Types::MerchantType", null: false, definition:
    47 def merchant
    48 @merchant ||= Merchant.lookup(merchant_id)
    49 end
    50 end
    

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93. Concepts :
    Dynamic Methods
    Unbound Methods
    

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94. Console Demo
    

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95. 4 class Payment < TargetBase
    5 mattr_accessor :gql_field_annotations do
    6 {}
    7 end
    9 . . .
    32 annotate_field "Integer", null: false, definition:
    33 def amount
    34 target_data.amount
    35 end
    36
    37 annotate_field "Types::BaseObject::ID", null: false, definition:
    38 def token
    39 target_data.token
    40 end
    41
    42 def merchant_id
    43 target_data.merchant_id
    44 end
    45
    46 annotate_field "Types::MerchantType", null: false, definition:
    47 def merchant
    48 @merchant ||= Merchant.lookup(merchant_id)
    49 end
    50 end
    

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96. 4 class Payment < TargetBase
    5 mattr_accessor :gql_field_annotations do
    6 {}
    7 end
    32 annotate_field "Integer", null: false, definition:
    33 def amount
    34 target_data.amount
    35 end
    

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97. 1 module TargetAnnotation
    2 def annotate_field(type, null: false, definition:)
    5 self.gql_field_annotations[definition] = {
    6 type: type,
    7 null: null
    8 }
    9
    10 orig_method = instance_method(definition)
    11 define_method(definition) do
    12 orig_method.bind(self).call
    13 end
    14 end
    15 end
    4 class Payment < TargetBase
    5 mattr_accessor :gql_field_annotations do
    6 {}
    7 end
    32 annotate_field "Integer", null: false, definition:
    33 def amount
    34 target_data.amount
    35 end
    

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98. 1 module TargetAnnotation
    2 def annotate_field(type, null: false, definition:)
    5 self.gql_field_annotations[definition] = {
    6 type: type,
    7 null: null
    8 }
    9
    10 orig_method = instance_method(definition)
    11 define_method(definition) do
    12 orig_method.bind(self).call
    13 end
    14 end
    15 end
    4 class Payment < TargetBase
    5 mattr_accessor :gql_field_annotations do
    6 {}
    7 end
    32 annotate_field "Integer", null: false, definition:
    33 def amount
    34 target_data.amount
    35 end
    

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99. 1 module TargetAnnotation
    2 def annotate_field(type, null: false, definition:)
    5 self.gql_field_annotations[definition] = {
    6 type: type,
    7 null: null
    8 }
    9
    10 orig_method = instance_method(definition)
    11 define_method(definition) do
    12 orig_method.bind(self).call
    13 end
    14 end
    15 end
    4 class Payment < TargetBase
    5 mattr_accessor :gql_field_annotations do
    6 {}
    7 end
    32 annotate_field "Integer", null: false, definition:
    33 def amount
    34 target_data.amount
    35 end
    

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100. 1 module TargetAnnotation
     2 def annotate_field(type, null: false, definition:)
     5 self.gql_field_annotations[definition] = {
     6 type: type,
     7 null: null
     8 }
     9
     10 orig_method = instance_method(definition)
     11 define_method(definition) do
     12 orig_method.bind(self).call
     13 end
     14 end
     15 end
     4 class Payment < TargetBase
     5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     32 annotate_field "Integer", null: false, definition:
     33 def amount
     34 target_data.amount
     35 end
     

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101. 1 module TargetAnnotation
     2 def annotate_field(type, null: false, definition:)
     5 self.gql_field_annotations[definition] = {
     6 type: type,
     7 null: null
     8 }
     9
     10 orig_method = instance_method(definition)
     11 define_method(definition) do
     12 orig_method.bind(self).call
     13 end
     14 end
     15 end
     4 class Payment < TargetBase
     5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     32 annotate_field "Integer", null: false, definition:
     33 def amount
     34 target_data.amount
     35 end
     :amount
     

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102. 1 module TargetAnnotation
     2 def annotate_field(type, null: false, definition:)
     5 self.gql_field_annotations[definition] = {
     6 type: type,
     7 null: null
     8 }
     9
     10 orig_method = instance_method(definition)
     11 define_method(definition) do
     12 orig_method.bind(self).call
     13 end
     14 end
     15 end
     4 class Payment < TargetBase
     5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     32 annotate_field "Integer", null: false, definition:
     33 def amount
     34 target_data.amount
     35 end
     

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103. 1 module TargetAnnotation
     2 def annotate_field(type, null: false, definition:)
     5 self.gql_field_annotations[definition] = {
     6 type: type,
     7 null: null
     8 }
     9
     10 orig_method = instance_method(definition)
     11 define_method(definition) do
     12 orig_method.bind(self).call
     13 end
     14 end
     15 end
     4 class Payment < TargetBase
     5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     32 annotate_field "Integer", null: false, definition:
     33 def amount
     34 target_data.amount
     35 end
     

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104. 1 module TargetAnnotation
     2 def annotate_field(type, null: false, definition:)
     5 self.gql_field_annotations[definition] = {
     6 type: type,
     7 null: null
     8 }
     9
     10 orig_method = instance_method(definition)
     11 define_method(definition) do
     12 orig_method.bind(self).call
     13 end
     14 end
     15 end
     4 class Payment < TargetBase
     5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     32 annotate_field "Integer", null: false, definition:
     33 def amount
     34 target_data.amount
     35 end
     :amount
     

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105. 1 module TargetAnnotation
     2 def annotate_field(type, null: false, definition:)
     5 self.gql_field_annotations[definition] = {
     6 type: type,
     7 null: null
     8 }
     9
     10 orig_method = instance_method(definition)
     11 define_method(definition) do
     12 orig_method.bind(self).call
     13 end
     14 end
     15 end
     4 class Payment < TargetBase
     5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     32 annotate_field "Integer", null: false, definition:
     33 def amount
     34 target_data.amount
     35 end
     

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106. 1 module TargetAnnotation
     2 def annotate_field(type, null: false, definition:)
     5 self.gql_field_annotations[definition] = {
     6 type: type,
     7 null: null
     8 }
     9
     10 orig_method = instance_method(definition)
     11 define_method(definition) do
     12 orig_method.bind(self).call
     13 end
     14 end
     15 end
     4 class Payment < TargetBase
     5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     32 annotate_field "Integer", null: false, definition:
     33 def amount
     34 target_data.amount
     35 end
     

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107. 1 module TargetAnnotation
     2 def annotate_field(type, null: false, definition:)
     5 self.gql_field_annotations[definition] = {
     6 type: type,
     7 null: null
     8 }
     9
     10 orig_method = instance_method(definition)
     11 define_method(definition) do
     12 orig_method.bind(self).call
     13 end
     14 end
     15 end
     4 class Payment < TargetBase
     5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     32 annotate_field "Integer", null: false, definition:
     33 def amount
     34 target_data.amount
     35 end
     

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108. 1 module TargetAnnotation
     2 def annotate_field(type, null: false, definition:)
     5 self.gql_field_annotations[definition] = {
     6 type: type,
     7 null: null
     8 }
     9
     10 orig_method = instance_method(definition)
     11 define_method(definition) do
     12 orig_method.bind(self).call
     13 end
     14 end
     15 end
     4 class Payment < TargetBase
     5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     32 annotate_field "Integer", null: false, definition:
     33 def amount
     34 target_data.amount
     35 end
     

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109. Let’s Generate the GQL Type Classes
     

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110. gql_type_generator = GqlTypeGenerator.new(all_target_classes)
     => {
     Payment: Types::PaymentType,
     Merchant: Types::MerchantType
     }
     => #@target_to_gql_class_mapping={Payment: Types::PaymentType,
     Merchant: Types::MerchantType}>
     gql_type_generator.target_to_gql_class_mapping
     gql_type_generator.target_to_gql_class_mapping[Payment]
     => Types::PaymentType
     gql_type_generator.target_to_gql_class_mapping[Merchant]
     => Types::MerchantType
     

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111. Concepts :
     Ruby Object Model
     Constants
     

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112. console demo
     

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113. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     5 @target_to_gql_class_mapping = {}
     6
     7 target_classes.each do |target_class|
     8 gql_type_class_name = "#{target_class.to_s}Type"
     9
     10 @target_to_gql_class_mapping[target_class] =
     11 Types.const_set(
     12 gql_type_class_name,
     13 Class.new(Types::BaseObject) do end
     16 )
     17 end
     18 end
     19 end
     

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114. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     5 @target_to_gql_class_mapping = {}
     6
     7 target_classes.each do |target_class|
     8 gql_type_class_name = "#{target_class.to_s}Type"
     9
     10 @target_to_gql_class_mapping[target_class] =
     11 Types.const_set(
     12 gql_type_class_name,
     13 Class.new(Types::BaseObject) do end
     16 )
     17 end
     18 end
     19 end
     

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115. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     5 @target_to_gql_class_mapping = {}
     6
     7 target_classes.each do |target_class|
     8 gql_type_class_name = "#{target_class.to_s}Type"
     9
     10 @target_to_gql_class_mapping[target_class] =
     11 Types.const_set(
     12 gql_type_class_name,
     13 Class.new(Types::BaseObject) do end
     16 )
     17 end
     18 end
     19 end
     

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116. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     5 @target_to_gql_class_mapping = {}
     6
     7 target_classes.each do |target_class|
     8 gql_type_class_name = "#{target_class.to_s}Type"
     9
     10 @target_to_gql_class_mapping[target_class] =
     11 Types.const_set(
     12 gql_type_class_name,
     13 Class.new(Types::BaseObject) do end
     16 )
     17 end
     18 end
     19 end
     

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117. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     5 @target_to_gql_class_mapping = {}
     6
     7 target_classes.each do |target_class|
     8 gql_type_class_name = "#{target_class}Type"
     9
     10 @target_to_gql_class_mapping[target_class] =
     11 Types.const_set(
     12 gql_type_class_name,
     13 Class.new(Types::BaseObject) do end
     16 )
     17 end
     18 end
     19 end
     

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118. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     5 @target_to_gql_class_mapping = {}
     6
     7 target_classes.each do |target_class|
     8 gql_type_class_name = "#{target_class}Type"
     9
     10 @target_to_gql_class_mapping[target_class] =
     11 Types.const_set(
     12 gql_type_class_name,
     13 Class.new(Types::BaseObject) do
     end
     16 )
     17 end
     18 end
     19 end
     

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119. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     5 @target_to_gql_class_mapping = {}
     6
     7 target_classes.each do |target_class|
     8 gql_type_class_name = "#{target_class}Type"
     9
     10 @target_to_gql_class_mapping[target_class] =
     11 Types.const_set(
     12 gql_type_class_name,
     13 Class.new(Types::BaseObject)
     16 )
     17 end
     18 end
     19 end
     

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120. 7 target_classes.each do |target_class|
     8 gql_type_class_name = "#{target_class}Type"
     9
     10 @target_to_gql_class_mapping[target_class] =
     11 Types.const_set(
     12 gql_type_class_name,
     13 Class.new(Types::BaseObject)
     16 )
     17 end
     1 class Types::PaymentType < Types::BaseObject
     2 field :id, ID, null: false
     3 field :amount, Int, null: false
     4 field :merchant, Types::MerchantType, null: false
     5 end
     

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121. 7 target_classes.each do |target_class|
     8 gql_type_class_name = "#{target_class}Type"
     9
     10 @target_to_gql_class_mapping[target_class] =
     11 Types.const_set(
     12 gql_type_class_name,
     13 Class.new(Types::BaseObject)
     16 )
     17 end
     1 class Types::PaymentType < Types::BaseObject
     2 field :id, ID, null: false
     3 field :amount, Int, null: false
     4 field :merchant, Types::MerchantType, null: false
     5 end
     

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122. 7 target_classes.each do |target_class|
     8 gql_type_class_name = "#{target_class}Type"
     9
     10 @target_to_gql_class_mapping[target_class] =
     11 Types.const_set(
     12 gql_type_class_name,
     13 Class.new(Types::BaseObject)
     16 )
     17 end
     1 class Types::PaymentType < Types::BaseObject
     2 field :id, ID, null: false
     3 field :amount, Int, null: false
     4 field :merchant, Types::MerchantType, null: false
     5 end
     

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123. 1 class Types::PaymentType < Types::BaseObject
     2 field :id, ID, null: false
     3 field :amount, Int, null: false
     4 field :merchant, Types::MerchantType, null: false
     5 end
     

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124. Types::PaymentType
     => Types::PaymentType
     Types::PaymentType.own_fields.keys
     => [“id”, “amount”, “merchant”]
     Types::PaymentType.own_fields[“id"].class
     => GraphQL::Schema::Field
     Types::MerchantType.own_fields[“id"]
     => #@underscored_name="id", @name="id", @description=nil, @field=nil,
     @function=nil . . .>
     

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125. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     . . .
     19
     20 def self.add_fields_to_gql_type(target_class, gql_type_class)
     22 target_class.gql_field_annotations.each do |field, def_hash|
     23 fieldType = field_definition_hash[:type].constantize
     24 nullable = field_definition_hash[:null]
     25 field field_name, fieldType, null: nullable
     26 end
     28 end
     29 end
     1 class Types::PaymentType < Types::BaseObject
     2 field :id, ID, null: false
     3 field :amount, Int, null: false
     4 field :merchant, Types::MerchantType, null: false
     5 end
     

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126. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     . . .
     19
     20 def self.add_fields_to_gql_type(target_class, gql_type_class)
     22 target_class.gql_field_annotations.each do |field, def_hash|
     23 fieldType = field_definition_hash[:type].constantize
     24 nullable = field_definition_hash[:null]
     25 field field_name, fieldType, null: nullable
     26 end
     28 end
     29 end
     1 class Types::PaymentType < Types::BaseObject
     2 field :id, ID, null: false
     3 field :amount, Int, null: false
     4 field :merchant, Types::MerchantType, null: false
     5 end
     

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127. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     . . .
     19
     20 def self.add_fields_to_gql_type(target_class, gql_type_class)
     22 target_class.gql_field_annotations.each do |field, def_hash|
     23 fieldType = field_definition_hash[:type].constantize
     24 nullable = field_definition_hash[:null]
     25 field field_name, fieldType, null: nullable
     26 end
     28 end
     29 end
     1 class Types::PaymentType < Types::BaseObject
     2 field :id, ID, null: false
     3 field :amount, Int, null: false
     4 field :merchant, Types::MerchantType, null: false
     5 end
     

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128. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     . . .
     19
     20 def self.add_fields_to_gql_type(target_class, gql_type_class)
     22 target_class.gql_field_annotations.each do |field, def_hash|
     23 fieldType = field_definition_hash[:type].constantize
     24 nullable = field_definition_hash[:null]
     25 field field_name, fieldType, null: nullable
     26 end
     28 end
     29 end
     1 class Types::PaymentType < Types::BaseObject
     2 field :id, ID, null: false
     3 field :amount, Int, null: false
     4 field :merchant, Types::MerchantType, null: false
     5 end
     

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129. 1 class GqlTypeGenerator
     2 attr_accessor :target_to_gql_class_mapping
     3
     4 def initialize(target_classes)
     . . .
     19
     20 def self.add_fields_to_gql_type(target_class, gql_type_class)
     22 target_class.gql_field_annotations.each do |field, def_hash|
     23 fieldType = field_definition_hash[:type].constantize
     24 nullable = field_definition_hash[:null]
     25 graph_type_class.field field_name, fieldType, null: nullable
     26 end
     28 end
     29 end
     1 class Types::PaymentType < Types::BaseObject
     2 field :id, ID, null: false
     3 field :amount, Int, null: false
     4 field :merchant, Types::MerchantType, null: false
     5 end
     

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130. gql_type_generator = GqlTypeGenerator
     .new(Target.all_target_classes)
     gql_type_generator
     .target_to_gql_class_mapping.each do |target, gql_type|
     GqlTypeGenerator.add_fields_to_gql_type(
     target_class, gql_type
     )
     end
     

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131. Types::QueryType
     Root Types
     Root Type Resolvers
     field :payment …
     field :merchant …
     def payment …
     def merchant …
     Types::PaymentType
     Types::MerchantType
     GQL Type Classes
     

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132. Types::QueryType
     Root Types
     Root Type Resolvers
     field :payment …
     field :merchant …
     def payment …
     def merchant …
     

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133. 1 module Types
     2 class QueryType < Types::BaseObject
     3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     6
     7 field :merchant, Types::MerchantType, null: false do
     8 argument :id, ID, required: true
     9 end
     10
     11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     14
     15 def merchant(params)
     16 Merchant.lookup(params[:id])
     17 end
     18 end
     19 end
     20
     

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134. 1 module Types
     2 class QueryType < Types::BaseObject
     3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     6
     7 field :merchant, Types::MerchantType, null: false do
     8 argument :id, ID, required: true
     9 end
     10
     11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     14
     15 def merchant(params)
     16 Merchant.lookup(params[:id])
     17 end
     18 end
     19 end
     20
     

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135. 1 module Types
     2 class QueryType < Types::BaseObject
     3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     6
     7 field :merchant, Types::MerchantType, null: false do
     8 argument :id, ID, required: true
     9 end
     10
     11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     14
     15 def merchant(params)
     16 Merchant.lookup(params[:id])
     17 end
     18 end
     19 end
     20
     3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     

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136. 3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     

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137. 1 module Types
     2 class QueryType < Types::BaseObject
     . . .
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     16 field field_name, gql_type, null: false do
     17 argument :id, ID, required: true
     18 end
     24 end
     25 end
     26 end
     27
     3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     

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138. 1 module Types
     2 class QueryType < Types::BaseObject
     . . .
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     16 field field_name, gql_type, null: false do
     17 argument :id, ID, required: true
     18 end
     24 end
     25 end
     26 end
     27
     3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     

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139. 1 module Types
     2 class QueryType < Types::BaseObject
     . . .
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     16 field field_name, gql_type, null: false do
     17 argument :id, ID, required: true
     18 end
     24 end
     25 end
     26 end
     27
     3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     

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140. 1 module Types
     2 class QueryType < Types::BaseObject
     . . .
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     16 field field_name, gql_type, null: false do
     17 argument :id, ID, required: true
     18 end
     24 end
     25 end
     26 end
     27
     3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     

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141. 3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     1 module Types
     2 class QueryType < Types::BaseObject
     3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     6
     7 field :merchant, Types::MerchantType, null: false do
     8 argument :id, ID, required: true
     9 end
     10
     11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     14
     15 def merchant(params)
     16 Merchant.lookup(params[:id])
     17 end
     18 end
     19 end
     20
     11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     

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142. 1 module Types
     2 class QueryType < Types::BaseObject
     3 field :payment, Types::PaymentType, null: false do
     4 argument :id, ID, required: true
     5 end
     6
     7 field :merchant, Types::MerchantType, null: false do
     8 argument :id, ID, required: true
     9 end
     10
     11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     14
     15 def merchant(params)
     16 Merchant.lookup(params[:id])
     17 end
     18 end
     19 end
     20
     11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     

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143. 11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     

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144. 11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     1 module Types
     2 class QueryType < Types::BaseObject
     12
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     . . .
     20 define_method(field_name) do |params|
     21 targetClass = Object.const_get(field_name.capitalize)
     22 targetClass.lookup(params[:id])
     23 end
     24 end
     25 end
     26 end
     27
     

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145. 11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     1 module Types
     2 class QueryType < Types::BaseObject
     12
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     . . .
     20 define_method(field_name) do |params|
     21 targetClass = Object.const_get(field_name.capitalize)
     22 targetClass.lookup(params[:id])
     23 end
     24 end
     25 end
     26 end
     27
     

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146. 11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     1 module Types
     2 class QueryType < Types::BaseObject
     12
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     . . .
     20 define_method(field_name) do |params|
     21 targetClass = Object.const_get(field_name.capitalize)
     22 targetClass.lookup(params[:id])
     23 end
     24 end
     25 end
     26 end
     27
     

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147. 11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     1 module Types
     2 class QueryType < Types::BaseObject
     12
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     . . .
     20 define_method(field_name) do |params|
     21 targetClass = Object.const_get(field_name.capitalize)
     22 targetClass.lookup(params[:id])
     23 end
     24 end
     25 end
     26 end
     27
     

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148. 11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     1 module Types
     2 class QueryType < Types::BaseObject
     12
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     . . .
     20 define_method(field_name) do |params|
     21 target_class = Object.const_get(field_name.capitalize)
     23 end
     24 end
     25 end
     26 end
     27
     

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149. 11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     1 module Types
     2 class QueryType < Types::BaseObject
     12
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     . . .
     20 define_method(field_name) do |params|
     21 target_class = Object.const_get(field_name.capitalize)
     22 target_class.lookup(params[:id])
     23 end
     24 end
     25 end
     26 end
     27
     

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150. 11 def payment(params)
     12 Payment.lookup(params[:id])
     13 end
     1 module Types
     2 class QueryType < Types::BaseObject
     12
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     . . .
     20 define_method(field_name) do |params|
     21 target_class = Object.const_get(field_name.capitalize)
     22 target_class.lookup(params[:id])
     23 end
     24 end
     25 end
     26 end
     27
     

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151. demo
     

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152. Let’s Add a New Target: Card
     

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153. Payment
     - id
     - amount
     - merchant_id
     Merchant
     - id
     - store_name
     Is associated through merchant_id
     Today’s Data Model
     

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154. Payment
     - id
     - amount
     - merchant_id
     Merchant
     - id
     - store_name
     Today’s Data Model
     Card
     - id
     - name_on_card
     - bin
     - payment_id
     

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155. 4 class Card < TargetBase
     5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     8
     9 stub_target_data(
     10 resource: 'card',
     11 id: 7890,
     12 response_body: {
     13 id: 7890,
     14 bin: 1111,
     15 names_on_card:'Shawnee Gao',
     16 postal_code: 94114,
     17 payment_id: 1234
     18 }
     19 )
     20
     21 def self._fetch_target_data(id)
     22 target_data = CardClient.get_by_id(id)
     23 OpenStruct.new(target_data)
     24 end
     . . .
     40
     41 def payment_id
     42 target_data.payment_id
     43 end
     44
     45 annotate_field "Types::PaymentType", null: false, definition:
     46 def payment
     47 @payment ||= Payment.lookup(payment_id)
     48 end
     49 end
     

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156. 5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     8
     9 stub_target_data(
     10 resource: 'card',
     11 id: 7890,
     12 response_body: {
     13 id: 7890,
     14 bin: 1111,
     15 names_on_card:'Shawnee Gao',
     16 postal_code: 94114,
     17 payment_id: 1234
     18 }
     19 )
     20
     21 def self._fetch_target_data(id)
     22 target_data = CardClient.get_by_id(id)
     23 OpenStruct.new(target_data)
     24 end
     . . .
     40
     41 def payment_id
     42 target_data.payment_id
     43 end
     44
     45 annotate_field "Types::PaymentType", null: false, definition:
     46 def payment
     47 @payment ||= Payment.lookup(payment_id)
     48 end
     

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157. 5 mattr_accessor :gql_field_annotations do
     6 {}
     7 end
     8
     9 stub_target_data(
     10 resource: 'card',
     11 id: 7890,
     12 response_body: {
     13 id: 7890,
     14 bin: 1111,
     15 names_on_card:'Shawnee Gao',
     16 postal_code: 94114,
     17 payment_id: 1234
     18 }
     19 )
     20
     21 def self._fetch_target_data(id)
     22 target_data = CardClient.get_by_id(id)
     23 OpenStruct.new(target_data)
     24 end
     . . .
     40
     41 def payment_id
     42 target_data.payment_id
     43 end
     44
     45 annotate_field "Types::PaymentType", null: false, definition:
     46 def payment
     47 @payment ||= Payment.lookup(payment_id)
     48 end
     49 end
     

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158. demo
     

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159. Requirements
     Change
     

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160. Payment
     - id
     - amount
     - merchant_id
     Merchant
     - id
     - store_name
     Today’s Data Model
     Card
     - id
     - name_on_card
     - bin
     - payment_id
     

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161. Payment
     - id
     - amount
     - merchant_id
     - card_id
     Merchant
     - id
     - store_name
     Today’s Data Model
     Is associated through merchant_id
     Card
     - id
     - name_on_card
     - bin
     associated through payment_id
     

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162. Types::QueryType
     Root Types
     Root Type Resolvers
     field :payment …
     field :merchant …
     def payment …
     def merchant …
     

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163. 1 module Types
     2 class QueryType < Types::BaseObject
     4 gql_type_generator = GqlTypeGenerator.new(Target.all_target_classes)
     . . .
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     16 field field_name, gql_type, null: false do
     17 argument :id, ID, required: true
     18 end
     24 end
     25 end
     26 end
     27
     

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164. 1 module Types
     2 class QueryType < Types::BaseObject
     4 gql_type_generator = GqlTypeGenerator.new(Target.all_target_classes)
     . . .
     12 valid_root_types_target_classes = [Payment, Merchant]
     13 gql_type_generator
     14 .target_to_gql_class_mapping.each do |target, gql_type|
     15 field_name = target.to_s.downcase.to_sym
     16 field field_name, gql_type, null: false do
     17 argument :id, ID, required: true
     18 end
     24 end
     25 end
     26 end
     27
     

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165. 1 module Types
     2 class QueryType < Types::BaseObject
     4 gql_type_generator = GqlTypeGenerator.new(Target.all_target_classes)
     . . .
     12 valid_root_type_targets = [Payment, Merchant]
     13 valid_root_type_targets.each do |target|
     14 gql_type_class =
     gql_type_generator.target_to_gql_class_mapping[target]
     15 field_name = target.to_s.downcase.to_sym
     16 field field_name, gql_type, null: false do
     17 argument :id, ID, required: true
     18 end
     24 end
     25 end
     26 end
     27
     

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166. demo
     

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167. Tests
     

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168. 1 require 'spec_helper'
     2
     3 describe "GqlTypeGenerator#initialize" do
     4 it 'creates a Target Class to GqlType Class mapping' do
     5 all_target_classes = Target.all_target_classes
     6 all_target_classes.each do |target_class|
     7 expect{ "Types::#{target_class.to_s}Type".constantize }.to raise_error(NameError)
     8 end
     9
     10 util = GqlTypeGenerator.new(all_target_classes)
     11
     12 all_target_classes.each do |target_class|
     13 gql_type_class_name = "Types::#{target_class.to_s}Type".constantize
     14 expect(gql_type_class_name).to be_instance_of Class
     15 util.target_to_gql_class_mapping[target_class] = gql_type_class_name
     16 end
     17 end
     18 end
     

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169. 1 require 'spec_helper'
     2
     3 describe "GqlTypeGenerator#initialize" do
     4 it 'creates a Target Class to GqlType Class mapping' do
     5 all_target_classes = Target.all_target_classes
     6 all_target_classes.each do |target_class|
     expect{ "Types::#{target_class.to_s}Type".constantize }.to raise_error(NameError)
     8 end
     9
     10 util = GqlTypeGenerator.new(all_target_classes)
     11
     12 all_target_classes.each do |target_class|
     13 gql_type_class_name = "Types::#{target_class.to_s}Type".constantize
     14 expect(gql_type_class_name).to be_instance_of Class
     15 util.target_to_gql_class_mapping[target_class] = gql_type_class_name
     16 end
     17 end
     18 end
     

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170. 1 require 'spec_helper'
     2
     3 describe "GqlTypeGenerator#initialize" do
     4 it 'creates a Target Class to GqlType Class mapping' do
     5 all_target_classes = Target.all_target_classes
     6 all_target_classes.each do |target_class|
     7 expect{ "Types::#{target_class.to_s}Type".constantize }.to raise_error(NameError)
     8 end
     9
     10 util = GqlTypeGenerator.new(all_target_classes)
     11
     12 all_target_classes.each do |target_class|
     13 gql_type_class_name = "Types::#{target_class.to_s}Type".constantize
     14 expect(gql_type_class_name).to be_instance_of Class
     15 util.target_to_gql_class_mapping[target_class] = gql_type_class_name
     16 end
     17 end
     18 end
     

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171. 1 require 'spec_helper'
     2
     3 describe "GqlTypeGenerator#initialize" do
     4 it 'creates a Target Class to GqlType Class mapping' do
     5 all_target_classes = Target.all_target_classes
     6 all_target_classes.each do |target_class|
     7 expect{ "Types::#{target_class.to_s}Type".constantize }.to raise_error(NameError)
     8 end
     9
     10 gql_type_generator = GqlTypeGenerator.new(all_target_classes)
     11
     12 all_target_classes.each do |target_class|
     13 gql_type_class_name = "Types::#{target_class.to_s}Type".constantize
     14 expect(gql_type_class_name).to be_instance_of Class
     15 util.target_to_gql_class_mapping[target_class] = gql_type_class_name
     16 end
     17 end
     18 end
     

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172. 1 require 'spec_helper'
     2
     3 describe "GqlTypeGenerator#initialize" do
     4 it 'creates a Target Class to GqlType Class mapping' do
     5 all_target_classes = Target.all_target_classes
     6 all_target_classes.each do |target_class|
     7 expect{ "Types::#{target_class.to_s}Type".constantize }.to raise_error(NameError)
     8 end
     9
     gql_type_generator = GqlTypeGenerator.new(all_target_classes)
     11
     12 all_target_classes.each do |target_class|
     13 gql_type_class_name = "Types::#{target_class.to_s}Type".constantize
     14 expect(gql_type_class_name).to be_instance_of Class
     15 util.target_to_gql_class_mapping[target_class] = gql_type_class_name
     16 end
     17 end
     18 end
     

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173. 1 require 'spec_helper'
     2
     3 describe "GqlTypeGenerator#initialize" do
     4 it 'creates a Target Class to GqlType Class mapping' do
     5 all_target_classes = Target.all_target_classes
     6 all_target_classes.each do |target_class|
     7 expect{ "Types::#{target_class.to_s}Type".constantize }.to raise_error(NameError)
     8 end
     9
     10 gql_type_generator = GqlTypeGenerator.new(all_target_classes)
     11
     12 all_target_classes.each do |target_class|
     13 gql_type_class_name = "Types::#{target_class.to_s}Type".constantize
     14 expect(gql_type_class_name).to be_instance_of Class
     15 util.target_to_gql_class_mapping[target_class] = gql_type_class_name
     16 end
     17 end
     18 end
     

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174. 1 require 'spec_helper'
     2
     3 describe "GqlTypeGenerator#initialize" do
     4 it 'creates a Target Class to GqlType Class mapping' do
     5 all_target_classes = Target.all_target_classes
     6 all_target_classes.each do |target_class|
     7 expect{ "Types::#{target_class.to_s}Type".constantize }.to raise_error(NameError)
     8 end
     9
     10 gql_type_generator = GqlTypeGenerator.new(all_target_classes)
     11
     12 all_target_classes.each do |target_class|
     13 gql_type_class_name = "Types::#{target_class.to_s}Type".constantize
     14 expect(gql_type_class_name).to be_instance_of Class
     15 gql_type_generator.target_to_gql_class_mapping[target_class] = gql_type_class_name
     16 end
     17 end
     18 end
     

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175. 1 require 'spec_helper'
     2
     3 describe "GqlTypeGenerator#initialize" do
     4 it 'creates a Target Class to GqlType Class mapping' do
     5 all_target_classes = Target.all_target_classes
     6 all_target_classes.each do |target_class|
     7 expect{ "Types::#{target_class.to_s}Type".constantize }.to raise_error(NameError)
     8 end
     9
     10 gql_type_generator = GqlTypeGenerator.new(all_target_classes)
     11
     12 all_target_classes.each do |target_class|
     13 gql_type_class_name = "Types::#{target_class.to_s}Type".constantize
     expect(gql_type_class_name).to be_instance_of Class
     gql_type_generator.target_to_gql_class_mapping[target_class] = gql_type_class_name
     16 end
     17 end
     18 end
     

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176. 1 require 'spec_helper'
     2
     . . .
     19
     20 describe "GqlTypeGenerator#add_annotated_target_fields_to_gql_type_class" do
     21 it 'creates a GqlType Class from Target constant' do
     22 Types::PaymentType = Class.new(Types::BaseObject)
     26 Types::MerchantType = Class.new(Types::BaseObject)
     27 annotated_target_fields_hash = Payment.gql_field_annotations.sort
     29
     30 GqlTypeGenerator
     31 .add_annotated_target_fields_to_gql_type_class(
     32 Payment, Types::PaymentType
     33 )
     34
     35 gql_type_fields_hash =
     36 Types::PaymentType.instance_variable_get(:@own_fields)
     37 .sort.to_h.symbolize_keys
     40
     41 annotated_target_fields_hash.each do |field_name, field_definition|
     42 expect(gql_type_fields_hash[field_name]
     43 .instance_variable_get(:@return_type_expr))
     44 .to eq(field_definition[:type].constantize)
     45
     46 expect(gql_type_fields_hash[field_name]
     47 .instance_variable_get(:@return_type_null))
     48 .to eq(field_definition[:null])
     49 end
     50
     51 end
     52 end
     

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177. 1 require 'spec_helper'
     2
     . . .
     19
     20 describe "GqlTypeGenerator#add_annotated_target_fields_to_gql_type_class" do
     21 it 'creates a GqlType Class from Target constant' do
     22 Types::PaymentType = Class.new(Types::BaseObject)
     26 Types::MerchantType = Class.new(Types::BaseObject)
     27 annotated_target_fields_hash = Payment.gql_field_annotations.sort
     29
     30 GqlTypeGenerator
     31 .add_annotated_target_fields_to_gql_type_class(
     32 Payment, Types::PaymentType
     33 )
     34
     35 gql_type_fields_hash =
     36 Types::PaymentType.instance_variable_get(:@own_fields)
     37 .sort.to_h.symbolize_keys
     40
     41 annotated_target_fields_hash.each do |field_name, field_definition|
     42 expect(gql_type_fields_hash[field_name]
     43 .instance_variable_get(:@return_type_expr))
     44 .to eq(field_definition[:type].constantize)
     45
     46 expect(gql_type_fields_hash[field_name]
     47 .instance_variable_get(:@return_type_null))
     48 .to eq(field_definition[:null])
     49 end
     50
     51 end
     52 end
     

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178. 1 require 'spec_helper'
     2
     . . .
     19
     20 describe "GqlTypeGenerator#add_annotated_target_fields_to_gql_type_class" do
     21 it 'creates a GqlType Class from Target constant' do
     22 Types::PaymentType = Class.new(Types::BaseObject)
     26 Types::MerchantType = Class.new(Types::BaseObject)
     27 annotated_target_fields_hash = Payment.gql_field_annotations.sort
     29
     30 GqlTypeGenerator
     31 .add_annotated_target_fields_to_gql_type_class(
     32 Payment, Types::PaymentType
     33 )
     34
     35 gql_type_fields_hash =
     36 Types::PaymentType.instance_variable_get(:@own_fields)
     37 .sort.to_h.symbolize_keys
     40
     41 annotated_target_fields_hash.each do |field_name, field_definition|
     42 expect(gql_type_fields_hash[field_name]
     43 .instance_variable_get(:@return_type_expr))
     44 .to eq(field_definition[:type].constantize)
     45
     46 expect(gql_type_fields_hash[field_name]
     47 .instance_variable_get(:@return_type_null))
     48 .to eq(field_definition[:null])
     49 end
     50
     51 end
     52 end
     

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179. 1 require 'spec_helper'
     2
     . . .
     19
     20 describe "GqlTypeGenerator#add_annotated_target_fields_to_gql_type_class" do
     21 it 'creates a GqlType Class from Target constant' do
     22 Types::PaymentType = Class.new(Types::BaseObject)
     26 Types::MerchantType = Class.new(Types::BaseObject)
     27 annotated_target_fields_hash = Payment.gql_field_annotations.sort
     29
     30 GqlTypeGenerator
     31 .add_annotated_target_fields_to_gql_type_class(
     32 Payment, Types::PaymentType
     33 )
     34
     35 gql_type_fields_hash =
     36 Types::PaymentType.instance_variable_get(:@own_fields)
     37 .sort.to_h.symbolize_keys
     40
     41 annotated_target_fields_hash.each do |field_name, field_definition|
     42 expect(gql_type_fields_hash[field_name]
     43 .instance_variable_get(:@return_type_expr))
     44 .to eq(field_definition[:type].constantize)
     45
     46 expect(gql_type_fields_hash[field_name]
     47 .instance_variable_get(:@return_type_null))
     48 .to eq(field_definition[:null])
     49 end
     50
     51 end
     52 end
     

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180. Wrap Up:
     Revisiting Our Checklist
     1.Flexible
     
     2.Reduce Boilerplate
     
     3.Improved Developer Experience
     

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181. shawneegao@gmail.com
     github@shawneegao
     @gao_shawnee
     

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182. Business Operations Platform Team at Square!!!
     

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183. haegwan@squareup.com
     Interested in developing with Square?
     

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184. The End!!!!!
     

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