For years, we had to write boring, duplicated code for our http endpoints: one for the frontend-side and one for the backend-side. Microservices added even more duplicated code. Once these got out of sync, we had to fix them manually. All of this frustrating "monkey coding" keeps us away from more important tasks. Swagger or OpenAPI is a set of tools to eliminate this problem. Supporting different languages and frameworks, Swagger’s code generator creates server stubs and clients of your API. It also provides a frontend where we can call the endpoints directly with predefined request data. Say farewell to Postman and other. A nice editor to define the API wraps it up. I will demonstrate the usefulness of Swagger and OpenAPI using an application based on Express and Angular. You will quickly see how these tools can free you to focus on code that matters.

1. Jumpstart into
Swagger & OpenAPI
(JS Edition)
GrazJS
14.8.2018
Rainer Hahnekamp
@rainerhahnekamp
GrazJS, 14.8.2018, Rainer Hahnekamp

2. Agenda
● Introduction to Swagger
● Coding Session "City-Info"
https://github.com/rainerhahnekamp/city-info-js
○ Backend in Express
○ Client in Node.JS
○ Frontend in Angular
GrazJS, 14.8.2018, Rainer Hahnekamp

3. Swagger / OpenAPI
Solution for developing, documenting and maintaining Web APIs
● Elements
○ URL Paths
○ Response Types
○ Request Types
● Code duplication
● On-Going synchronisation efforts
● Resulting bugs
GrazJS, 14.8.2018, Rainer Hahnekamp

4. The Ecosystem
Specification
v2 = Swagger Spec.
v3 = OpenAPI
Documentation
Editor
Tools
GrazJS, 14.8.2018, Rainer Hahnekamp

5. Server Stubs
and many more
Client
and many more
SpringFox Swashbuckle
others
Tools
API First
(Code Generators)Code First
GrazJS, 14.8.2018, Rainer Hahnekamp

6. Summary
● OpenAPI as Specification
● Swagger brand for various tools around OpenAPI from SmartBear
● Portfolio
○ Documentation
○ Editor
○ Code Generators
○ Other Tools
● OpenAPI tools not exclusively from SmartBear. SpringFox or Swashbuckle
as examples, various plugins for IDE, external documentation libraries, etc.
● Code-First vs. Documentation-First approach
● OpenAPI Initiative
● OpenAPITools as Fork for code generators
GrazJS, 14.8.2018, Rainer Hahnekamp