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How to use OpenAPI3 for API developer (RubyKaig...

ota42y
April 18, 2019

How to use OpenAPI3 for API developer (RubyKaigi 2019)

ota42y

April 18, 2019
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  1. Today’s Topic • Introduce OpenAPI 3 and explain why it

    is necessary • The OpenAPI 3 specification • How to use OpenAPI 3 • Request / response validation • A story about how to implement OpenAPI 3 feature • Other OpenAPI 3 tools
  2. about me • @ota42y (github/twitter) • Server side engineer at

    FiNC Technologies • I maintain request/response validation gem using OpenAPI 3
  3. 2F

  4. OpenAPI 3 • programming language-agnostic definition for REST API •

    OpenAPI 3 means OpenAPI specification version 3 • previously known as Swagger so Swagger 2 == OpenAPI 2 https://www.openapis.org/
  5. Definition of OpenAPI 3 • It’s machine-readable API definition rule

    • Definition of OpenAPI 3 is described in YAML or JSON formats • We can use it as interactive document generation, validation, mock-server, client library, etc…(I’ll talk about it later)
  6. Sometimes the machine-readable API schema is important • When we

    create many APIs • When we want to do schema-first development • etc…
  7. When we create many APIs • Backend API server for

    iOS/Android/Web(SPA) • We have many JSON APIs
 (We use microservices architecture so 1000 over endpoints ) • API schema is very important for interface documentation
  8. Schema first development • Schema first development • Define API

    schema • Client-side and server-side implement according it • Integration test • Without Schema first development, 
 we can’t start client-side implement until server side implement finished Reference: RubyKaigi 2017 API Development in 2017 https://www.youtube.com/watch?v=a28jJ62ZfZM Rails Developers Meetup 2019: 
 https://speakerdeck.com/aeroastro/rails-meets-protocol-buffers-for-schema-first-development
  9. Definition and implementation must be always same • If there

    are difference we can’t trust API schema • Even if we passed unit test, we gets bug on integration test • But it’s difficult to avoid making mistakes
  10. The machine-readable API schema is important • We can find

    mistakes API automatically using the schema • So always the schema and definition is matched • We can use schema to generate human-readable docs, client library, etc…
  11. OpenAPI is one of the definition method • JSON Hyper-Schema

    • It defines hypermedia specifications, and it can also be used to define REST API too • GraphQL • Query language and runtime • The response can be specified in the query sent from the client
  12. OpenAPI is one of the definition method • gRPC •

    RPC framework using protocol buffers and HTTP/2 • It generates code from interface definition and do almost all communication processing
  13. OpenAPI extends REST API • OpenAPI is just a YAML/JSON

    rule • Actual processing is just REST API • OpenAPI 3 takes full advantage of existing RESTful frameworks and insights • Since REST is a web best practice at the time, various mechanisms such as HTTP cache, monitoring system can also be used
  14. Example API get "/apps" do content_type :json # page should

    be Integer page = params["page"] [page, (page*10)].map(&:to_s).to_json end
  15. get "/apps" do content_type :json # page should be Integer

    page = params["page"] [page, (page*10)].map(&:to_s).to_json end • GET /apps returns application/json Example API
  16. get "/apps" do content_type :json # page should be Integer

    page = params["page"].to_i [page, (page*10)].map(&:to_s).to_json end • GET /apps returns application/json • This API requires `page` parameter and must be Integer Example API
  17. get "/apps" do content_type :json # page should be Integer

    page = params["page"].to_i [page, (page*10)].map(&:to_s).to_json end • GET /apps returns application/json • This API requires `page` parameter and must be Integer • Succeed response includes string array Example API
  18. Example API to OpenAPI 3 definition openapi: 3.0.0 info: title:

    Sample API version: 0.1.0 paths: "/apps": get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string
  19. Example API to OpenAPI 3 definition • GET /apps openapi:

    3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps": get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string
  20. Example API to OpenAPI 3 definition • GET /apps returns

    application/json openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps": get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string
  21. Example API to OpenAPI 3 definition • GET /apps returns

    application/json • `page` parameter required and it’s integer openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps": get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string
  22. Example API to OpenAPI 3 definition • GET /apps returns

    application/json • `page` parameter required and it’s integer • Succeed response includes string array openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps": get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string
  23. Example API to OpenAPI 3 definition • GET /apps returns

    application/json • `page` parameter required and it’s integer • Succeed response includes string array openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps": get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string
  24. OpenAPI 3 structure JOGP QBUIT TFSWFST DPNQPOFOUT TFDVSJUZ UBHT FYUFSOBM%PDT

    required Metadata for this definition API definitions Target server setting Schema objects Security settings Tags External document url
  25. OpenAPI 3 structure JOGP QBUIT TFSWFST DPNQPOFOUT TFDVSJUZ UBHT FYUFSOBM%PDT

    required Metadata for this definition API definitions Target server setting Schema objects Security settings Tags External document url
  26. openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps":

    get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string Paths Object • API definitions are written in this section • There is path string key and 
 Path Item Object • We can write definition in Path Item Object Path string Path Item Object
  27. openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps":

    get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string Path Item Object • Define request/response parameter 
 per HTTP method Path Item Object
  28. Path Item Object • Define request/response parameter 
 per HTTP

    method • We can define request parameter openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps": get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string
  29. Path Item Object • Define request/response parameter 
 per HTTP

    method • We can define request parameter and 
 response parameter schema openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps": get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string
  30. OpenAPI 3 structure JOGP QBUIT TFSWFST DPNQPOFOUT TFDVSJUZ UBHT FYUFSOBM%PDT

    required Metadata for this definition API definitions Target server setting Schema objects Security settings Tags External document url
  31. Security Scheme Object • We can define security schema for

    all API or specific API • We can use HTTP authentication type: http scheme: basic type: http scheme: bearer bearerFormat: JWT JWT basic
  32. Security Scheme Object • We can define security schema for

    all API or specific API • We can use HTTP authentication, API key (like header, query) type: http scheme: basic type: apiKey name: api_key in: header type: http scheme: bearer bearerFormat: JWT JWT API key basic
  33. Security Scheme Object • We can define security schema for

    all API or specific API • We can use HTTP authentication, API key (like header, query), 
 OAuth2, OpenID Connect type: http scheme: basic type: apiKey name: api_key in: header type: http scheme: bearer bearerFormat: JWT JWT API key basic type: oauth2 flows: implicit: authorizationUrl: https://example.co... scopes: write:pets: modify pets read:pets: read your pets OAuth2
  34. OpenAPI 3 structure JOGP QBUIT TFSWFST DPNQPOFOUT TFDVSJUZ UBHT FYUFSOBM%PDT

    required openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps": get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string
  35. OpenAPI is definition • It’s just a rule in YAML/JSON

    file, so it alone does nothing • It is effective by combining it with peripheral tools • request/response validation, interactive document generation, mock-server, client library, etc…
  36. We need validation • We make mistakes when implementing the

    API • OpenAPI is programming language-agnostic definition
  37. We need validation • We make mistakes when implementing the

    API • OpenAPI is programming language-agnostic definition • So we need a tool to check differences between implementation and definition
  38. We need validation • We make mistakes when implementing the

    API • OpenAPI is programming language-agnostic definition • So we need a tool to check differences between implementation and definition • This will ensure the credibility of the schema
  39. committee gem • Request/Response validation gem • This gem works

    as Rack middleware and performs validation if requested URL is in definition 3BDL
 "QQMJDBUJPO $MJFOU "QQMJDBUJPO Request validation Response validation committee
  40. Request validation using committee require "sinatra" require "committee" use Committee::Middleware::RequestValidation,

    schema_path: 'schema.yaml' use Committee::Middleware::ResponseValidation, schema_path: 'schema.yaml' get "/apps" do content_type :json # page should be Integer page = params["page"].to_i [page, (page*10)].map(&:to_s).to_json end
  41. require "sinatra" require "committee" use Committee::Middleware::RequestValidation, schema_path: 'schema.yaml' use Committee::Middleware::ResponseValidation,

    schema_path: 'schema.yaml' get "/apps" do content_type :json # page should be Integer page = params["page"].to_i [page, (page*10)].map(&:to_s).to_json end Request validation using committee committee returns error without `page` parameter % curl -X GET "http://localhost:4567/apps" {"id":"bad_request","message":"required parameters page not exist in #/paths/~1apps/get”}
  42. Request validation using committee % curl -X GET "http://localhost:4567/apps" {"id":"bad_request","message":"required

    parameters page not exist in #/paths/~1apps/get”} % curl -X GET "http://localhost:4567/apps?page=1" ["1","10"] When `page` parameter exists, get correct response require "sinatra" require "committee" use Committee::Middleware::RequestValidation, schema_path: 'schema.yaml' use Committee::Middleware::ResponseValidation, schema_path: 'schema.yaml' get "/apps" do content_type :json # page should be Integer page = params["page"].to_i [page, (page*10)].map(&:to_s).to_json end
  43. % curl -X GET "http://localhost:4567/apps?page=1" ["1","1111111111"] require "sinatra" require "committee"

    # use Committee::Middleware::RequestValidation, schema_path: 'schema.yaml' # use Committee::Middleware::ResponseValidation, schema_path: 'schema.yaml' get "/apps" do content_type :json # page should be Integer page = params["page"] [page, (page*10)].map(&:to_s).to_json end Coerce request parameter Normally, request parameters don’t have type and are always string
  44. % curl -X GET "http://localhost:4567/apps?page=1" ["1","10"] Coerce request parameter But

    committee converts class using definition type (optional feature) require "sinatra" require "committee" use Committee::Middleware::RequestValidation, schema_path: 'schema.yaml' use Committee::Middleware::ResponseValidation, schema_path: 'schema.yaml' get "/apps" do content_type :json # page should be Integer page = params["page"] [page, (page*10)].map(&:to_s).to_json end
  45. Coerce request body and other convert % curl -X POST

    -H "Content-Type: application/json" -d '{"measured_at":"2016-04-01T16:00:00+09:00"}' “http://localhost:4567/apps" {"class":"DateTime"} post: requestBody: content: application/json: schema: type: object properties: measured_at: type: string format: date-time responses: '201': description: no content content: 'application/json': schema: type: object properties: class: type: string • committee coerce parameter in request body • When string in date-time format, 
 committee converts it to DateTime class
  46. Response validation using committee require "sinatra" require "committee" use Committee::Middleware::RequestValidation,

    schema_path: 'schema.yaml' use Committee::Middleware::ResponseValidation, schema_path: 'schema.yaml' get "/apps" do content_type :json # page should be Integer page = params["page"].to_i [page, (page*10)].to_json end This API returns string array but when returns integer array (we should call `map(&:to_s)` )
  47. require "sinatra" require "committee" use Committee::Middleware::RequestValidation, schema_path: 'schema.yaml' use Committee::Middleware::ResponseValidation,

    schema_path: 'schema.yaml' get "/apps" do content_type :json # page should be Integer page = params["page"].to_i [page, (page*10)].to_json end We get error response from committee And we can change to write log and return the response Response validation using committee % curl -X GET "http://localhost:4567/apps?page=1" {"id":"invalid_response","message":"1 class is Integer but it's not valid string in #/paths/~1apps/get/responses/200/content/application~1json/schema/items"}
  48. Test Assertions describe "GET /apps" do it "conforms to schema"

    do get '/apps?page=1' assert_schema_conform end end % bundle exec ruby committee_test.rb Run options: --seed 62877 # Running: E Finished in 0.023367s, 42.7954 runs/s, 0.0000 assertions/s. 1) Error: Committee::Middleware::Stub::GET /apps#test_0001_conforms to schema: Committee::InvalidResponse: don't exist status code definition in #/paths/~1apps/get/responses • committee provides response format checker for test • When there’re difference, test will fail
  49. committee secures the reliability • Committee supports request/response validation •

    We can check if it’s a valid request and response by unit test or integration test • So we can trust that the interface is correctly implemented along with the schema
  50. Inside committee • The committee initially supported only JSON Hyper-Schema

    and OpenAPI 2 validation • So I added new validation feature using OpenAPI 3 to committee
  51. Tight coupling with JSON Hyper- Schema • committee converted OpenAPI

    2 to JSON Hyper-Schema so committee validated one schema only • Validator was strongly coupled to JSON Hyper-Schema
  52. • OpenAPI 3 structure is different from JSON Hyper-Schema and

    • OpenAPI 3 have many new features (like security) • I decided to refactoring and implement a new validator for OpenAPI 3 Implement new validator
  53. Refactoring in committee • The committee does three steps •

    Rack layer processing • Find the schema from the request SBDLNJEEMFXBSF +40/)ZQFS4DIFNB 4DIFNB URL + HTTP method
  54. SBDLNJEEMFXBSF Refactoring in committee • The committee does three steps

    • Rack layer processing • Find the schema from the request • Validation using schema +40/)ZQFS4DIFNB 7BMJEBUPS validate 4DIFNB QBSBNFUFS
  55. SBDLNJEEMFXBSF Refactoring in committee • The committee does three steps

    • Rack layer processing • Find the schema from the request • Validation using schema +40/)ZQFS4DIFNB 7BMJEBUPS validate 4DIFNB QBSBNFUFS Depends on 
 JSON Hyper-Schema
  56. Refactoring schema finder SBDLNJEEMFXBSF +40/)ZQFS4DIFNB 4DIFNB URL + HTTP method

    • Rack middleware pass URL and HTTP method to definition and get schema so don’t need to know detail of definition
  57. Abstracted schema definition • So I create abstracted schema class

    and made rack middleware depend on it URL + HTTP method %FpOJUJPO SBDLNJEEMFXBSF
  58. Abstracted schema definition +40/)ZQFS4DIFNB URL + HTTP method %FpOJUJPO SBDLNJEEMFXBSF

    • So I create abstracted schema class and made rack middleware depend on it • The middleware don’t care it’s JSON Hyper-Schema or OpenAPI 3
  59. 0QFO"1* Abstracted schema definition URL + HTTP method %FpOJUJPO SBDLNJEEMFXBSF

    • So I create abstracted schema class and made rack middleware depend on it • The middleware don’t care it’s JSON Hyper-Schema or OpenAPI 3
  60. Refactoring validator • Rack middleware validate using schema object from

    definition and request/response data from rack • But middleware don’t need to know more about schema SBDLNJEEMFXBSF 7BMJEBUPS validate 4DIFNB QBSBNFUFS +40/)ZQFS4DIFNB %FpOJUJPO
  61. SBDLNJEEMFXBSF Abstracted validator • I create abstracted validator which include

    schema definition • The middleware gets it from definition URL + HTTP method %FpOJUJPO "CTUSBDUWBMJEBUPS 4DIFNB +40/)ZQFS4DIFNB +40/)ZQFS4DIFNB
  62. Abstracted validator • The middleware passes parameter to the validator

    for validation %FpOJUJPO "CTUSBDU7BMJEBUPS 4DIFNB +40/)ZQFS4DIFNB +40/)ZQFS4DIFNB QBSBNFUFS validate SBDLNJEEMFXBSF
  63. Abstracted validator • The middleware passes parameter to the validator

    for validation • So rack middleware don’t need to know the definition is OpenAPI 3 or JSON Hyper-Schema %FpOJUJPO "CTUSBDU7BMJEBUPS 4DIFNB 0QFO"1* 0QFO"1* QBSBNFUFS validate SBDLNJEEMFXBSF
  64. Abstracted validator • The middleware passes parameter to the validator

    for validation • So rack middleware don’t need to know the definition is OpenAPI 3 or JSON Hyper-Schema %FpOJUJPO "CTUSBDU7BMJEBUPS 4DIFNB 0QFO"1* 0QFO"1* QBSBNFUFS validate SBDLNJEEMFXBSF
  65. openapi_parser gem • OpenAPI 3 parser is separated gem
 https://github.com/ota42y/openapi_parser

    • So we can implement another gem for OpenAPI 3 validation
 (e.g. more Ruby on ̋̋̋̋̋ friendly validator) • OpenAPI 3 parser is separated gem
 https://github.com/ota42y/openapi_parser • So we can implement another gem for OpenAPI 3 validation
 (e.g. more Ruby on ̋̋̋̋̋ friendly validator)
  66. Inside openapi_parser gem • OpenAPI 3 parser has 3 feature

    • Mapping definition data to Ruby object • Finding schema from path and HTTP method • Validating parameter using schema
  67. Mapping OpenAPI definition to object • OpenAPI 3 definition have

    many object openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps": get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string
  68. Mapping OpenAPI definition to object • OpenAPI 3 definition have

    many object • Definition is YAML/JSON file so 
 ruby loads it as Hash objects • openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps": get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string
  69. Mapping OpenAPI definition to object • openapi_parser map definition data

    to Ruby object using DSL • I implemented few methods to these classes module OpenAPIParser::Schemas class Parameter < Base openapi_attr_values :name, :in, :description, :req openapi_attr_value :allow_empty_value, schema_key: openapi_attr_value :allow_reserved, schema_key: :a def validate_params(params, options)
  70. Inside openapi_parser gem • OpenAPI 3 parser has 3 feature

    • Mapping definition data to Ruby object • Finding schema from path and HTTP method • Validating parameter using schema
  71. openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps":

    get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string • Schema is defined separately for each HTTP method in Path Item Object Find schema from URL Path Item Object Path string
  72. openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps":

    get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string • Schema is defined separately for each HTTP method in Path Item Object Find schema from URL Path Item Object
  73. openapi: 3.0.0 info: title: Sample API version: 0.1.0 paths: "/apps":

    get: parameters: - name: page in: query required: true schema: type: integer responses: '200': description: example content: 'application/json': schema: type: array items: type: string • Schema is defined separately for each HTTP method in Path Item Object • So we should find Path Item Object from requested URL Find schema from URL Path Item Object Path string
  74. OpenAPI 3 support path parameter paths: "/pets/mine": … Requested path

    Definition path /pets/mine -> "/pets/mine" 

  75. OpenAPI 3 support path parameter paths: "/pets/mine": … "/pets/{petId}": …

    Requested path Definition path /pets/mine -> "/pets/mine" /pets/1 -> "/pets/{petId}" /pets/2 -> "/pets/{petId}" 

  76. OpenAPI 3 support path parameter paths: "/pets/mine": … "/pets/{petId}": …

    "/pets/0": … Requested path Definition path /pets/mine -> "/pets/mine" /pets/1 -> "/pets/{petId}" /pets/2 -> "/pets/{petId}" /pets/0 -> "/pets/0" 
 /pets/1/food -> "/pets/{petId}/food" /pets/0/food -> "/pets/0/food/" • If there are both with and without parameters, the one without parameters takes precedence
  77. OpenAPI 3 support path parameter paths: "/pets/mine": … "/pets/{petId}": …

    "/pets/0": … Requested path Definition path /pets/mine -> "/pets/mine" /pets/1 -> "/pets/{petId}" /pets/2 -> "/pets/{petId}" /pets/0 -> "/pets/0" 
 /pets/1/food -> "/pets/{petId}/food" /pets/0/food -> "/pets/0/food/" • If there are both with and without parameters, the one without parameters takes precedence • So we should find Path Item Object according this rule
  78. Support many API • If we are using JSON Hyper-Schema

    in committee, do the same thing but it was a full search • But we have many API ( One server had up to 500 APIs) • So we want to more efficient data structure
  79. • Patricia tree is space-optimized trie tree • All nodes

    have string value and child node have parent’s prefix Patricia tree Patricia trie.svg: Claudio Rocchini CC-BY 2.5
  80. • Divide defined path by `/` and create node Patricia

    tree for path string users /users/meals/me me meals
  81. • Divide defined path by `/` and create node •

    Build tree Patricia tree for path string users /users/meals/me me meals
  82. • Divide defined path by `/` and create node •

    Build tree Patricia tree for path string users meals me
  83. • Divide defined path by `/` and create node •

    Build tree • Add new path’s nodes Patricia tree for path string users /users/meals/{id} {id} meals users meals me
  84. • Divide defined path by `/` and create node •

    Build tree • Add new path’s nodes • If there is same node, skip it and use shared node Patricia tree for path string users meals me users {id} meals
  85. • Divide defined path by `/` and create node •

    Build tree • Add new path’s nodes • If there is same node, skip it and use shared node Patricia tree for path string users meals me users {id} meals
  86. • Divide defined path by `/` and create node •

    Build tree • Add new path’s nodes • If there is same node, skip it and use shared node Patricia tree for path string users users meals me {id} meals
  87. • Divide defined path by `/` and create node •

    Build tree • Add new path’s nodes • If there is same node, skip it and use shared node Patricia tree for path string users users meals me {id} meals
  88. • Divide defined path by `/` and create node •

    Build tree • Add new path’s nodes • If there is same node, skip it and use shared node Patricia tree for path string users {id} meals users meals me
  89. • Divide defined path by `/` and create node •

    Build tree • Add new path’s nodes • If there is same node, skip it and use shared node • Add all paths Patricia tree for path string users {id} meals users meals me
  90. lunch • Divide requested URL by `/` too • Find

    node from root {id} users meals me steps lunch /users/meals/42/lunch public root Find defined path from patricia tree
  91. lunch • Divide requested URL by `/` too • Find

    node from root Find defined path from patricia tree {id} users meals me steps lunch /users/meals/42/lunch public root
  92. lunch • Divide requested URL by `/` too • Find

    node from root Find defined path from patricia tree {id} users meals me steps lunch /users/meals/42/lunch public root
  93. lunch • Divide requested URL by `/` too • Find

    node from root Find defined path from patricia tree {id} users meals me steps lunch /users/meals/42/lunch public root
  94. lunch • Divide requested URL by `/` too • Find

    node from root • If there isn’t matched node, 
 use parameter node (OpenAPI 3 definition) Find defined path from patricia tree {id} users meals me steps lunch /users/meals/42/lunch public root
  95. lunch • Divide requested URL by `/` too • Find

    node from root • If there isn’t matched node, 
 use parameter node (OpenAPI 3 definition) Find defined path from patricia tree {id} users meals me steps lunch /users/meals/42/lunch public root
  96. lunch • Divide requested URL by `/` too • Find

    node from root • If there isn’t matched node, 
 use parameter node (OpenAPI 3 definition) Find defined path from patricia tree {id} users meals me steps lunch /users/meals/42/lunch public root
  97. lunch • Divide requested URL by `/` too • Find

    node from root • If there isn’t matched node, 
 use parameter node (OpenAPI 3 definition) Find defined path from patricia tree {id} users meals me steps lunch /users/meals/42/lunch public root
  98. lunch • Divide requested URL by `/` too • Find

    node from root • If there isn’t matched node, 
 use parameter node (OpenAPI 3 definition) Find defined path from patricia tree {id} users meals me steps lunch /users/meals/{id}/lunch public root
  99. lunch • Divide requested URL by `/` too • Find

    node from root • If there isn’t matched node, 
 use parameter node (OpenAPI 3 definition) • Get Path Item Object from matched Find defined path from patricia tree {id} users meals me steps lunch /users/meals/{id}/lunch public root
  100. • When we find a schema, we can validate the

    parameter • OpenAPI 3 schema is subset of the JSON Schema Specification Wright Draft 00 Parameter validation
  101. schema: type: object nullable: false properties: nickname: type: string string,

    boolean, integer • There are few types of schema in JSON Schema Parameter validation schema: type: string format: email schema: type: array items: type: object required: - id properties: id: type: integer object array
  102. • JSON Schema has `string`, `boolean`, `integer` type • These

    can be mapped same Ruby class so it’s easy to check Standard validation schema: type: string format: email
  103. • JSON Schema has `object` type Object validation schema: type:

    object nullable: false properties: nickname: type: string
  104. • JSON Schema has `object` type • This type has

    `properties` which has property name and schema Object validation schema: type: object nullable: false properties: nickname: type: string
  105. • JSON Schema has `object` type • This type has

    `properties` which has property name and schema • This type can be mapped to Hash in ruby 
 and property name is represented as hash key Object validation schema: type: object nullable: false properties: nickname: type: string
  106. • JSON Schema has `object` type • This type has

    `properties` which has property name and schema • This type can be mapped to Hash in ruby 
 and property name is represented as hash key Object validation schema: type: object nullable: false properties: nickname: type: string schema.properties.each do |name, child_schema| child_schema.validate(parameter[name]) end
  107. • The `array` type in JSON Schema which can be

    mapped Array Array validation schema: type: array items: type: object required: ...
  108. • The `array` type in JSON Schema which can be

    mapped Array • The `array` type has items schema definition Array validation schema: type: array items: type: object required: ...
  109. • The `array` type in JSON Schema which can be

    mapped Array • The `array` type has items schema definition • Check all item in array is according to schema Array validation schema: type: array items: type: object required: ... array_parameter.all? do |item| items_schema.validate(item) end
  110. openapi_parser include these methods • These feature is implemented in

    openapi_parser
 and it’s separated from committee
  111. openapi_parser include these methods • These feature is implemented in

    openapi_parser
 and it’s separated from committee # load OpenAPI 3 definition root = OpenAPIParser.parse(YAML.load_file('open_api_3/schema.yml'))
  112. openapi_parser include these methods • These feature is implemented in

    openapi_parser
 and it’s separated from committee # load OpenAPI 3 definition root = OpenAPIParser.parse(YAML.load_file('open_api_3/schema.yml')) # get schema from HTTP method (POST) and path (/validate) op = root.request_operation(:post, '/validate')
  113. openapi_parser include these methods • These feature is implemented in

    openapi_parser
 and it’s separated from committee # load OpenAPI 3 definition root = OpenAPIParser.parse(YAML.load_file('open_api_3/schema.yml')) # get schema from HTTP method (POST) and path (/validate) op = root.request_operation(:post, '/validate') # validate request body ret = op.validate_request_body('application/json', params)
  114. openapi_parser include these methods • These feature is implemented in

    openapi_parser
 and it’s separated from committee • So if you want to create OpenAPI 3 tool, this gem help for you # load OpenAPI 3 definition root = OpenAPIParser.parse(YAML.load_file('open_api_3/schema.yml')) # get schema from HTTP method (POST) and path (/validate) op = root.request_operation(:post, '/validate') # validate request body ret = op.validate_request_body('application/json', params)
  115. OpenAPI Generator • Generate API client and Server stub from

    OpenAPI definition • Many language and framework supported (OpenAPI Generator is a folk of Swagger Codegen)
  116. Generate Ruby gem • This generator generates API client library

    as gem • You can try this command (using docker) % docker run --rm -w /local -v ${PWD}:/local openapitools/openapi-generator-cli \ generate \ -i schema.yaml \ -g ruby \ -o output_dir
  117. Generated gem • One method is created for one HTTP

    method definition api_instance = OpenapiClient::DefaultApi.new page = 56 result = api_instance.apps_get(page)
  118. Generated gem • One method is created for one HTTP

    method definition api_instance = OpenapiClient::DefaultApi.new page = 56 result = api_instance.apps_get(page) GET /apps
  119. Generated gem • One method is created for one HTTP

    method • If you want to divide by namespace, use tags in OpenAPI 3
 (OpenAPI 3 allow add tag per HTTP method) api_instance = OpenapiClient::DefaultApi.new page = 56 result = api_instance.apps_get(page) users_api = OpenapiClient::UsersApi.new limit = 10 users_api.blogs_get(limit)
  120. Document Included • OpenAPI 3 supports markdown description for many

    objects • OpenAPI Generator convert request / response parameter as method argument and return value and outputs these as YARD style comments with description # get app names by array # @param page specific page setting # @param [Hash] opts the optional parameters # @return [Array<String>] def apps_get(page, opts = {})
  121. Generete type definition…? • I think we can generate type

    definition (.rbi) class DefaultApi def apps_get: (page: Integer) -> Array<String> end
  122. Generete type definition…? • I think we can generate type

    definition (.rbi) • And we can generate server side code like Hanami with .rbi class DefaultApi def apps_get: (page: Integer) -> Array<String> end module Web module Controllers module Home class Index include Web::Action def call(params) end end
  123. Interactive Document • Swagger UI provide 
 interactive document 


    (but no Ruby… ) • It provides human-readable
 documents and the ability to
 try out a request
  124. Convert OpenAPI 2 to OpenAPI 3 • There is OpenAPI

    2 to OpenAPI 3 converter • https://mermade.org.uk/openapi-converter
  125. JSON Hyper-Schema to OpenAPI 3 • I created JSON Hyper-Schema

    to OpenAPI 3 • https://github.com/ota42y/json_hyperscheme_to_openapi3
  126. JSON Hyper-Schema to OpenAPI 3 • I created JSON Hyper-Schema

    to OpenAPI 3 • https://github.com/ota42y/json_hyperscheme_to_openapi3 • But we need additional data to convert
  127. JSON Hyper-Schema to OpenAPI 3 • I created JSON Hyper-Schema

    to OpenAPI 3 • https://github.com/ota42y/json_hyperscheme_to_openapi3 • But we need additional data to convert • We need path parameter as additional data "/pets/{id}": get: parameters: - name: id in: path schema: type: integer
  128. Other tools • Mock server • Definition converter (e.g. OpenAPI

    3 to protocol buffers) • Please see OpenAPI.Tools site
 (https://openapi.tools/)
  129. Summary • We can use OpenAPI 3 to define API

    schema • OpenAPI 3 has various tools • Request/Respones validation • Client library generation • Interactive document • If you want to create new OpenAPI tool, it’s not so difficult
  130. Summary • We can use OpenAPI 3 to define API

    schema • OpenAPI 3 has various tools • Request/Respones validation • Client library generation • Interactive document • If you want to create new OpenAPI tool, it’s not so difficult
  131. Summary • We can use OpenAPI 3 to define API

    schema • OpenAPI 3 has various tools • Request/Respones validation • Client library generation • Interactive document • If you want to create new OpenAPI tool, it’s not so difficult
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  133. Do you use committee in production? • Yes • We

    use request validator and coerce all value in production • But we don’t use response validator in production, we use staging only • Because if we implement request/response by correct in staging, we don’t need check in production • committee has parameter coercer so we use request validation in production
  134. Committee is slow? • It is a benchmark result •

    Small benchmark have 1 query parameter • Big benchmark have 2600 objects • Check enable/disable committee and request 1000 times • I don’t check response validation benchmark because we don’t use it in production • Benchmark script is here
 https://gist.github.com/ota42y/3ed68a2cb0dc7c98122bdfd1a696ab72
  135. Small result • 1000 times request • So committee need

    0.2 milliseconds in every request VTFS TZTUFN UPUBM SFBM /PU6TF     6TF    
  136. Big result • Validate 2600 objects by 6 milliseconds
 (

    In many cases, it is about 100 at most, so I think that there is no problem) VTFS TZTUFN UPUBM SFBM /PU6TF     6TF