Building a Swift Web API and Application Together

Transcript

1. Building a Swift Web API and Application Together Kyle Fuller

2. Agenda —API Design —Building API in Swift —Deploying API in

   Swift in production

3. API Design

4. What makes a good API?

5. What makes a good API? —Decoupled from implementation details —Able

   to evolve without breaking existing clients

6. Example: Pagination

7. GET /posts

8. GET /posts{?page}

9. GET /posts?page=2

10. None
11. None

12. ! How can we solve?

13. GET /posts{?before}

14. GET /posts?before=44

15. How do we introduce changes to our API?

16. Versioning APIs

17. /v1/posts{?page} /v2/posts{?before}

18. /posts{?page} /posts{?before}

19. API is coupled to implementation details

20. API is coupled to implementation details

21. What happens when you version an API?

22. What happens when you version an API?

23. How can we design the API without exposing implementation details?

24. REST Representational State Transfer

25. Anticipating change is one of the central themes of REST

26. Evolvability

27. Tight Coupling

28. "You can’t have evolvability if clients have their controls baked

    into their design at deployment"

29. "Controls have to be learned on the fly. That’s what

    hypermedia enables"

30. Hypermedia

31. Web Linking RFC 5988

32. GET /posts Link: </posts?before=30>; rel="next", </posts?before=120>; rel="last"

33. GET /posts?before=120 Link: </posts?before=90>; rel="prev", </posts>; rel="first"

34. WebLinking.swift https://github.com/kylef/WebLinking.swift

35. WebLinking: Checking for next link if let link = response.findLink(relation:

    "next") { print("We have a next link with the URI: \(link.uri).") }

36. WebLinking: Introspecting Available Links for link in response.links { print("Relation:

    \(link.relationType)") print("URI: \(link.uri)") }

37. application/hal+json

38. Blog Post { "title": "My First Blog Post", "body": "Lorem

    Ipsum" }

39. Blog Post (Next Link) { "title": "My First Blog Post",

    "body": "Lorem Ipsum", "_links": [ { "href": "/posts/2", "relation": "next" } ] }

40. Blog Post (Self) { "title": "My First Blog Post", "body":

    "Lorem Ipsum", "_links": [ { "href": "/posts/1", "relation": "self" }, { "href": "/posts/2", "relation": "next" } ] }

41. Blog Post (Comments) { "title": "My First Blog Post", "body":

    "Lorem Ipsum", "_links": [ { "href": "/posts/1", "relation": "self" }, { "href": "/posts/2", "relation": "next" }, { "href": "/posts/1/comments", "relation": "comments" }, ] }

42. Blog Post (Embedded Comments) { "_embed": { "comments": [ {

    "author": "Kyle", "body": "That's a really interesting post!" "_links": [ { "href": "/posts/1/comments/1", "relation": "self" } ] } ] } }

43. application/ vnd.siren+json

44. Delete Post { "properties": { "title": "My First Blog Post",

    "body": "Lorem Ipsum", }, "actions": [ { "name": "delete", "method": "DELETE", "href": "/posts/1" } ] }

45. Delete Post { "properties": { "title": "My First Blog Post",

    "body": "Lorem Ipsum", }, "actions": [ { "name": "delete", "method": "DELETE", "href": "/posts/1" } ] }

46. Create Comment { "properties": { "title": "My First Blog Post",

    "body": "Lorem Ipsum", }, "actions": [ { "name": "comment", "method": "POST", "href": "/posts/1/comments", "fields": [ { "name": "author", "type": "string" }, { "name": "message", "type": "string" } ] } ] }

47. Create Comment (Logged in) { "properties": { "title": "My First

    Blog Post", "body": "Lorem Ipsum", }, "actions": [ { "name": "comment", "method": "POST", "href": "/posts/1/comments", "fields": [ { "name": "message", "type": "string" } ] } ] }

48. Hypermedia —Remove implementation details from interface —Keep business logic on

    back-end, not front-end

49. Building an API in Swift

50. Web Frameworks

51. Web Frameworks —Frank —IBM Kitura —Vapor

52. Frank vs Kitura vs Vapor

53. Frank get("users", *) { (request, username: String) in return "Hello

    \(username)" }

54. Server APIs Working Group

55. Server APIs Working Group

56. Useful Tools —Templating Languages —Stencil —Data Persistence —Redis (Redbird) —PostgreSQL

57. Testing

58. XCTest class PersonTests: XCTestCase { let person = Person(name: "Kyle")

    func testPersonName() { XCTAssertEqual(person.name, "Kyle") } func testPersonDescription() { XCTAssertEqual(person.description, "Kyle") } }

59. extension PersonTests: XCTestCaseProvider { var allTests : [(String, () throws

    -> Void)] { return [ ("testPersonName", testPersonName), ("testPersonDescription", testPersonDescription), ] } } XCTMain([ PersonTests(), ])

60. Dredd https://github.com/apiaryio/dredd

61. API Blueprint # GET /hello + Response 200 (application/json) {

    "name": "Kyle" }

62. Dredd Testing $ dredd \ apidescription.apib \ https://localhost:8080 ✔ GET

    /hello ✔ API Matches API Description

63. Deployment

64. https://github.com/kylef/heroku-buildpack-swift

65. $ cat Package.swift import PackageDescription let package = Package( name:

    "Hello", dependencies: [ .Package(url: "https://github.com/nestproject/Frank.git", majorVersion: 0, minor: 3), ] )

66. $ cat Sources/main.swift import Frank get { _ in return

    "Hello World" } get(*) { (_, username: String) in return "Hello \(username)" }

67. $ cat Sources/main.swift import Frank get { _ in return

    "Hello World" } get(*) { (_, username: String) in return "Hello \(username)" }

68. $ cat .swift-version 3.0.2

69. $ cat .swift-version 3.0.2

70. $ swift build $ .build/debug/Hello [INFO] Listening at http://0.0.0.0:8000 (48827)

    [INFO] Booting worker process with pid: 48828

71. $ cat Procfile web: Hello

72. $ heroku create --buildpack https://github.com/kylef/heroku-buildpack-swift.git $ git push heroku master

    remote: -----> Swift app detected remote: -----> Installing 3.0.2 remote: -----> Installing clang-3.7.0 remote: -----> Building Package remote: -----> Copying binaries to 'bin'
73. None
74. None
75. None

76. Manual Deployment

77. Monitoring

78. Logging

79. print("ERROR: Connection to database failed \(error)")

80. Papertrail

81. None
82. None

83. Conclusion —API Design —Swift Web Services —Tools & Frameworks —Testing

    —Deployment —Monitoring

84. Conclusion —API Design —Swift Web Services —Tools & Frameworks —Testing

    —Deployment —Monitoring

85. kylefuller https://fuller.li/talks