![[A] constructive approach to the problem of program
correctness [is] a usual technique to make a program and
then to test it. But, program testing can be a very effective
way to show the presence of bugs, it is hopelessly
inadequate for showing their absence. The only effective
way to raise the confidence level of a program significantly
is to give a convincing proof of its correctness.
-- Edsger, Wybe Di jkstra, ACM Turing Lecture, The Humble Programmer, 1972](https://image.slidesharecdn.com/gyi26dbotxoqxzokdgce-signature-83b95af04a975adbe529fb401a0a1180fedb7a85ec0646c574ac8537cc016738-poli-160418110304/85/API-First-with-play-and-swagger-56-320.jpg)
API First with play and swagger
- 1. API First with Play and Swagger
- 2. Some points mentioned in the “The Art of Decomposing Monoliths” talk: *Akka vs Microservices *proper contract testing *forward/backward compatibility *proper JSON marshalling *DRY
- 6. @ZALANDO
- 7. @ZALANDO
- 8. @ZALANDO
- 10. •Autonomy •Small in size •Full responsibility •One or more components
- 22. •Autonomy •Full responsibility •One system boundary
- 23. API First Document and peer review API before writing a single line of code Ideally, generate either your server interfaces or your test data (or both) from the spec
- 25. Specification Server Implementation Review Client Implementation MisinterpretationMisrepresentation
- 26. DRY Dave Thomas Most people take DRY to mean you shouldn't duplicate code. That's not its intention. The idea behind DRY is far grander than that. DRY says that every piece of system knowledge should have one authoritative, unambiguous representation.
- 27. Specification is software It should be a single source of truth about the system
- 28. Specification
- 29. Specification
- 30. Specification
- 35. REST • Client-Server • Stateless • Cacheable • Layered System • Uniform Interface • Identification of resources • Manipulation of resources through these representations • Self-descriptive messages • Hypermedia as the engine of application state
- 36. REST • Self-descriptive messages • Hypermedia as the engine of application state
- 37. REST APIs must be hypertext-driven • “A REST API should spend almost all of its descriptive effort in defining the media type(s) used for representing resources and driving application state, or in defining extended relation names and/or hypertext-enabled mark-up for existing standard media types.” Roy T. Fielding
- 39. ClientServer Resource representation Resource representation Hypermedia controls Resource representation
- 42. Architecture
- 43. aka Ports and Adapters Chris Fidao https://www.youtube.com/watch?v=6SBjKOwVq0o
- 50. Getting real…
- 51. • Easy to use • Human readable • Widest adoption • Open Source • Scala and Java • Dynamic recompilation / Hot reload • Asynchronous IO • Easy to use
- 52. • URI path definitions (supports parameterisation and templating) • URI parameter definitions • Response definitions • Scheme definitions • MIME type definitions • Primitive datatypes • Complex datatypes • Structural constraints • Value constraints • Security constraints • Tags • Vendor extensions
- 55. Specification URLs Verbs Parameters Security Definitions Validations Model Test Data Validations Play Routes Marshallers Tests Controllers Security
- 56. [A] constructive approach to the problem of program correctness [is] a usual technique to make a program and then to test it. But, program testing can be a very effective way to show the presence of bugs, it is hopelessly inadequate for showing their absence. The only effective way to raise the confidence level of a program significantly is to give a convincing proof of its correctness. -- Edsger, Wybe Di jkstra, ACM Turing Lecture, The Humble Programmer, 1972
- 58. Types are specifications of possible values complying to that Type Types describe the rules that values must comply to A possibility to generate ranges of data values for given Types John Hughes, Haskell’s Quick Check
- 59. Boolean: True or False Equality: Equal or Not Equal Ordering: Greater, Equal or Less Provable
- 60. Numbers Strings Pretty much anything not composed from Provables Falsifiable
- 63. DEMO
- 65. Questions?