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
• 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)
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
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
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…
• 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
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
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
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
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
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
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…
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
as Rack middleware and performs validation if requested URL is in definition 3BDL "QQMJDBUJPO $MJFOU "QQMJDBUJPO Request validation Response validation committee
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
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”}
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
# 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
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
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)` )
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"}
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
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
• Rack layer processing • Find the schema from the request • Validation using schema +40/)ZQFS4DIFNB 7BMJEBUPS validate 4DIFNB QBSBNFUFS Depends on JSON Hyper-Schema
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
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
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
• 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)
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)
"/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
"/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
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
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
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
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
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
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
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
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
`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
`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
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
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')
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)
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)
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)
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 = {})
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
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
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
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
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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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
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
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![% curl -X GET "http://localhost:4567/apps?page=1" ["1","1111111111"] require "sinatra" require "committee"](https://files.speakerdeck.com/presentations/b845fc6d69694c619c9739f425c80e5a/slide_52.jpg){kind=link}
![% curl -X GET "http://localhost:4567/apps?page=1" ["1","10"] Coerce request parameter But](https://files.speakerdeck.com/presentations/b845fc6d69694c619c9739f425c80e5a/slide_53.jpg){kind=link}
