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Basta Fall 2019 OpenAPI

Basta Fall 2019 OpenAPI

This session shows how to document your ASP.NET Core Web API using Swashbuckle Swagger, enrich the resulting document, use that to automatically generate client code for API usage and postman collections for testing.

Sample code can be found at: https://github.com/thinktecture/basta-fall-2019-openapi

Sebastian Gingter

September 26, 2019

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  1. 1

  2. 10 Advanced ASP.NET Core Web APIs OpenAPI Initiative Linux Foundation

    TL;DR; OpenAPI = Specification Swagger = Tooling
  3. 13 • dotnet new webapi • • /api/weatherForecast • •

    • /weatherForecast, /health, /article • /weatherForecast (paged), /health, /article (paged) • /health, /article (paged) Advanced ASP.NET Core Web APIs
  4. 14 • Document methods / endpoints • Document model /

    schema information • Enrich this as much as possible • Exclude certain endpoints from documentation • Enable AuthN & AuthZ with Swagger UI • Combine with API Versioning • Customize documentation UI • Generate client code to consume our API • Test our API Advanced ASP.NET Core Web APIs
  5. 17 • Why we need Web API documentation • What

    is OpenAPI and Swagger • Swashbuckle.Swagger can automatically generate that for us • Swagger UI enables developers to explore our API interactively • The document can be used to generate client code • The document can be used to generate test boilerplates • We don’t have to do that manually and safe a lot of tedious work & time Advanced ASP.NET Core Web APIs
  6. 19 • OpenAPI • Formerly Swagger Specification & Tools by

    Smartbear Software • Open Source as well as commercial / closed source components • Smartbear Software & other companies (Google, IBM & Microsoft) started the Open API Initiative in Nov. 2015 under the umbrella of the Linux Foundation • Smartbear contributed its Swagger specification to the initiative • The initiative released the official OpenAPI specification 3.0 in Oct. 2017 • Smartbear Software continues to maintain their Swagger toolings (Swagger Editor, Swagger CodeGen, Swagger UI, etc.) • TL;DR; • OpenAPI = Specification • Swagger = Tooling Advanced ASP.NET Core Web APIs
  7. 20 • Documentation • Endpoints and data structures / schemas

    • Example data, example calls • Understandable • Explorable • Searchable • Ideally as much automated as possible • Ideally as multi-purpose as possible Advanced ASP.NET Core Web APIs
  8. 21 • .NET (luckily) offers a lot of metadata at

    runtime • Tooling is capable of automatically extracting a lot of documentation-relevant data directly from our IL code • Swashbuckle.Swagger for .NET (Core) projects • From Richard Morris (Getty Images, not Smartbear) • Automatically generates an OpenAPI document (swagger.json) using a custom Swagger Generator • Automatically displays a web page with our Web API documentation using Swagger UI from Smartbear Advanced ASP.NET Core Web APIs
  9. 22 • To be able to use a Web API,

    you need some sort of client • Web API clients usually consist of a ton of boilerplate code • They only differ in parameters, body format, http method and response format • All of that is known and documented • All information in available in our OpenAPI 3.0 document (swagger.json) • We can use that to automatically generate clients Advanced ASP.NET Core Web APIs
  10. 23 • When we write endpoints, we want to make

    sure they really work as expected • Postman helps in manual & automated testing • Setting up all the requests manually is tedious • Postman can import our swagger.json to pre-fill most of our requests • Postman tests use • Chai Assertion Library • tv4 (Tiny Validator for v4 JSON Schema) (marked as deprecated) • Ajv (Another JSON Schema Validator) (still needs manual import) Advanced ASP.NET Core Web APIs
  11. 24 • https://github.com/thinktecture/basta-fall-2019-openapi • https://speakerdeck.com/phoenixhawk/basta-fall-2019-openapi • https://www.openapis.org/ • https://swagger.io/ •

    https://github.com/domaindrivendev/Swashbuckle.AspNetCore • https://github.com/microsoft/aspnet-api-versioning • https://github.com/swagger-api/swagger-codegen • https://www.getpostman.com/ • https://www.npmjs.com/package/newman Advanced ASP.NET Core Web APIs