spray: REST on Akka (Scala Days)

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  • spray: REST on Akka (Scala Days)

    1. 1. REST on Akka Scala DaysApril 17th, 2012
    2. 2. What is spray?
    3. 3. What is spray?Vision: Provide the best toolkit for REST/HTTPand low-level network-IO on top of Akka
    4. 4. What is spray?Vision: Provide the best toolkit for REST/HTTPand low-level network-IO on top of Akka• First released about 1 year ago
    5. 5. What is spray?Vision: Provide the best toolkit for REST/HTTPand low-level network-IO on top of Akka• First released about 1 year ago• Principles: lightweight, async, non-blocking, actor-based, modular, few deps, testable
    6. 6. What is spray?Vision: Provide the best toolkit for REST/HTTPand low-level network-IO on top of Akka• First released about 1 year ago• Principles: lightweight, async, non-blocking, actor-based, modular, few deps, testable• Philosophy: set of libraries, not framework
    7. 7. Current State
    8. 8. Current StateTransitioning from Akka 1.3 to Akka 2.0
    9. 9. Current StateTransitioning from Akka 1.3 to Akka 2.0• spray 0.9.0 for Akka 1.3 released in March
    10. 10. Current StateTransitioning from Akka 1.3 to Akka 2.0• spray 0.9.0 for Akka 1.3 released in March• spray 1.0-M1 for Akka 2.0 two weeks ago
    11. 11. Current StateTransitioning from Akka 1.3 to Akka 2.0• spray 0.9.0 for Akka 1.3 released in March• spray 1.0-M1 for Akka 2.0 two weeks ago• Next: second milestone of spray 1.0
    12. 12. Current StateTransitioning from Akka 1.3 to Akka 2.0• spray 0.9.0 for Akka 1.3 released in March• spray 1.0-M1 for Akka 2.0 two weeks ago• Next: second milestone of spray 1.0 Focus of this talk
    13. 13. Componentsspray-routing spray-clientspray-servlet spray-can spray-json spray-http spray-io
    14. 14. Componentsspray-routing spray-clientspray-servlet spray-can spray-json spray-http spray-io Low-level, “actorized” network IO
    15. 15. Components spray-routing spray-client spray-servlet spray-can spray-json spray-http spray-iorich immutable HTTP model (no Akka)
    16. 16. Componentsspray-routing spray-clientspray-servlet spray-can spray-json low-level HTTP server and client spray-http spray-io
    17. 17. Components spray-routing spray-client spray-servlet spray-can spray-json Servlet APIadapter layer spray-http spray-io
    18. 18. Components spray-routing spray-clientDSL for server-side API construction spray-servlet spray-can spray-json spray-http spray-io
    19. 19. Componentsspray-routing spray-client Complementary high- level HTTP clientspray-servlet spray-can spray-json spray-http spray-io
    20. 20. Componentsspray-routing spray-clientspray-servlet spray-can spray-json straight JSON in Scala (no Akka) spray-http spray-io
    21. 21. Components spray-routing spray-client Focus for therest of the talk spray-servlet spray-can spray-json spray-http spray-io
    22. 22. spray-routing
    23. 23. spray-routing• Runs on spray-servlet or spray-can
    24. 24. spray-routing• Runs on spray-servlet or spray-can• Tool for building a “self-contained” API layer
    25. 25. spray-routing• Runs on spray-servlet or spray-can• Tool for building a “self-contained” API layer• Central element: Routing DSL for defining web API behavior
    26. 26. spray-routing• Runs on spray-servlet or spray-can• Tool for building a “self-contained” API layer• Central element: Routing DSL for defining web API behavior• Focus: RESTful web API, not web GUI
    27. 27. Basic Architecture Application Business Logic
    28. 28. Basic ArchitectureREST API layer Application Routing Logic Business Logic
    29. 29. Basic Architecture REST API layer ApplicationHTTP Request Routing Logic Business Logic
    30. 30. Basic Architecture REST API layer ApplicationHTTP Request Action Routing Logic Business Logic
    31. 31. Basic Architecture REST API layer ApplicationHTTP Request Action domain Routing object ! Business Logic Logic
    32. 32. Basic Architecture REST API layer ApplicationHTTP Request Action domain Routing object ! Business Logic Logic Reply
    33. 33. Basic Architecture REST API layer ApplicationHTTP Request Action domain Routing object ! Business Logic Logic Reply
    34. 34. Basic Architecture REST API layer ApplicationHTTP Request Action domain Routing object ! Business Logic LogicHTTP Response Reply
    35. 35. API Layer Responsibilities
    36. 36. API Layer Responsibilities• Request routing based on method, path, query parameters, entity
    37. 37. API Layer Responsibilities• Request routing based on method, path, query parameters, entity• (Un)marshalling to / from domain objects
    38. 38. API Layer Responsibilities• Request routing based on method, path, query parameters, entity• (Un)marshalling to / from domain objects• Encoding / decoding (compression)
    39. 39. API Layer Responsibilities• Request routing based on method, path, query parameters, entity• (Un)marshalling to / from domain objects• Encoding / decoding (compression)• Authentication / authorization
    40. 40. API Layer Responsibilities• Request routing based on method, path, query parameters, entity• (Un)marshalling to / from domain objects• Encoding / decoding (compression)• Authentication / authorization• Caching and serving static content
    41. 41. API Layer Responsibilities• Request routing based on method, path, query parameters, entity• (Un)marshalling to / from domain objects• Encoding / decoding (compression)• Authentication / authorization• Caching and serving static content• RESTful error handling
    42. 42. API Building in spray
    43. 43. API Building in spray• HTTP messages are actor messages
    44. 44. API Building in spray• HTTP messages are actor messages class PingServiceActor extends Actor { def receive = { case HttpRequest(GET, "/ping", _, _, _) => sender ! HttpResponse(200, "PONG") } }
    45. 45. API Building in spray• HTTP messages are actor messages class PingServiceActor extends Actor { def receive = { case HttpRequest(GET, "/ping", _, _, _) => sender ! HttpResponse(200, "PONG") } }• Could build services only via pattern-matching
    46. 46. API Building in spray• HTTP messages are actor messages class PingServiceActor extends Actor { def receive = { case HttpRequest(GET, "/ping", _, _, _) => sender ! HttpResponse(200, "PONG") } }• Could build services only via pattern-matching• But: pattern-matching becomes awkward for more complex service definitions
    47. 47. API Building in spray: DSLSimple example:class MyServiceActor extends Actor with Routing { def receive = receiveFromRoute { path("order" / HexIntNumber) { id => get { completeWith { "Received GET request for order " + id } } ~ put { completeWith { "Received PUT request for order " + id } } } }}
    48. 48. sprays Routing DSL
    49. 49. sprays Routing DSL• Built from recombinant elements called “directives”
    50. 50. sprays Routing DSL• Built from recombinant elements called “directives”• Concise, readable, maintainable
    51. 51. sprays Routing DSL• Built from recombinant elements called “directives”• Concise, readable, maintainable• Highly composable
    52. 52. sprays Routing DSL• Built from recombinant elements called “directives”• Concise, readable, maintainable• Highly composable• Type-safe
    53. 53. sprays Routing DSL• Built from recombinant elements called “directives”• Concise, readable, maintainable• Highly composable• Type-safe• Easily extensible with custom constructs
    54. 54. sprays Routing DSL• Built from recombinant elements called “directives”• Concise, readable, maintainable• Highly composable• Type-safe• Easily extensible with custom constructs• Directly interfaces with Akka API
    55. 55. Routing BasicsRoutes in spray: type Route = RequestContext => Unit
    56. 56. Routing BasicsRoutes in spray: type Route = RequestContext => Unit Explicit continuation- passing style
    57. 57. Routing BasicsRoutes in spray: type Route = RequestContext => Unit Explicit continuation- passing styleCentral object: case class RequestContext( request: HttpRequest, ...) {   def complete(...) { ... }   def reject(...) { ... }   ... }
    58. 58. Routing BasicsThe simplest route: ctx => ctx.complete("Say hello to spray")
    59. 59. Routing BasicsThe simplest route: ctx => ctx.complete("Say hello to spray")or: _.complete("Say hello to spray")
    60. 60. Routing BasicsThe simplest route: ctx => ctx.complete("Say hello to spray")or: _.complete("Say hello to spray")or using a “directive”: completeWith("Say hello to spray")
    61. 61. Routing BasicsThe simplest route: ctx => ctx.complete("Say hello to spray")or: _.complete("Say hello to spray")or using a “directive”: completeWith("Say hello to spray") def completeWith[T :Marshaller](value: => T): Route = _.complete(value)
    62. 62. DirectivesRoute structure built with directives:val route: Route = path("order" / HexIntNumber) { id => get { completeWith { "Received GET request for order " + id } }~ put { completeWith { "Received PUT request for order " + id } } }
    63. 63. Directives Route structure built with directives: val route: Route = path("order" / HexIntNumber) { id => get { completeWith { "Received GET request for order " + id }directive }~ name put { completeWith { "Received PUT request for order " + id } } }
    64. 64. DirectivesRoute structure built with directives:val route: Route = path("order" / HexIntNumber) { id => get { completeWith { "Received GET request for order " + id } }~ args put { completeWith { "Received PUT request for order " + id } } }
    65. 65. DirectivesRoute structure built with directives:val route: Route = path("order" / HexIntNumber) { id => get { extractions completeWith { "Received GET request for order " + id } }~ put { completeWith { "Received PUT request for order " + id } } }
    66. 66. DirectivesRoute structure built with directives:val route: Route = path("order" / HexIntNumber) { id => get { completeWith { "Received GET request for order " + id } }~ put { completeWith { "Received PUT request for order " + id } } inner route }
    67. 67. DirectivesRoute structure built with directives:val route: Route = path("order" / HexIntNumber) { id => get { completeWith { "Received GET request for order " + id }~ } route concatenation: put { recover from rejections completeWith { "Received PUT request for order " + id } } }
    68. 68. DirectivesRoute structure built with directives:val route: Route = path("order" / HexIntNumber) { id => get { completeWith { "Received GET request for order " + id } }~ put { completeWith { "Received PUT request for order " + id } } }
    69. 69. DirectivesRoute structure built with directives:val route: Route = path("order" / HexIntNumber) { id => get { completeWith { "Received GET request for order " + id } }~ put { completeWith { "Received PUT request for order " + id } } Route structure } forms a tree!
    70. 70. Directivesspray 0.9.0 comes with 69 predefined directives:alwaysPass, authenticate, authorize, autoChunk, cache, cacheResults, clientIP,completeWith, content, cookie, decodeRequest, delete, deleteCookie, detach,dynamic, encodeResponse, filter, filter1, filter2, filter3, filter4, filter5, filter6,filter7, filter8, filter9, formField, formFields, get, getFromDirectory, getFromFile,getFromFileName, getFromResource, getFromResourceDirectory, handleWith,hardFail, head, headerValue, headerValuePF, host, jsonpWithParameter, method,optionalCookie, options, parameter, parameters, path, pathPrefix, post,produce, provide, put, redirect, reject, respondWithContentType,respondWithHeader, respondWithHeaders, respondWithMediaType,respondWithStatus, setCookie, trace, transformChunkedResponse,transformRejections, transformRequest, transformRequestContext,transformResponse, transformRoute, transformUnchunkedResponse, validate
    71. 71. Real World Examplelazy val route = { encodeResponse(Gzip) { path("") { get { redirect("/doc") } }~ pathPrefix("api") { jsonpWithParameter("callback") { path("top-articles") { get { parameter(max.as[Int]) { max => validate(max >= 0, "query parameter max must be >= 0") { completeWith { (topArticlesService ? max).mapTo[Seq[Article]] } } } } }~ tokenAuthenticate { user => path("ranking") { get { countAndTime(user, "ranking") { parameters(fixed ? 0, mobile ? 0, sms ? 0, mms ? 0,
    72. 72. } } }~ } } Real World Example tokenAuthenticate { user => path("ranking") { get { countAndTime(user, "ranking") { parameters(fixed ? 0, mobile ? 0, sms ? 0, mms ? 0, data ? 0).as(RankingDescriptor) { descr => (rankingService ? Ranking(descr)).mapTo[RankingResult] } } } }~ path("accounts") { post { authorize(user.isAdmin) { content(as[AccountDetails]) { details => (accountService ? NewAccount(details)).mapTo[OpResult] } } } }~ path("account" / IntNumber) { accountId => get { ... } ~ put { ... } ~ delete { ... } } }}~pathPrefix("v1") {
    73. 73. } }~ Real World Example path("account" / IntNumber) { accountId => get { ... } ~ put { ... } ~ delete { ... } } } }~ pathPrefix("v1") { proxyToDjango } }~ pathPrefix("doc") { respondWithHeader(`Cache-Control`(`max-age`(3600))) { transformResponse(_.withContentTransformed(markdown2Html)) { getFromResourceDirectory("doc/root", pathRewriter = appendFileExt) } } }~ }~ cacheIfEnabled { encodeResponse(Gzip) { getFromResourceDirectory("public") } }}
    74. 74. Best Practices
    75. 75. Best Practices• Keep route structure clean and readable, pull out all logic into custom directives
    76. 76. Best Practices• Keep route structure clean and readable, pull out all logic into custom directives• Don’t let API layer leak into application
    77. 77. Best Practices• Keep route structure clean and readable, pull out all logic into custom directives• Don’t let API layer leak into application• Use (Un)marshalling infrastructure
    78. 78. Best Practices• Keep route structure clean and readable, pull out all logic into custom directives• Don’t let API layer leak into application• Use (Un)marshalling infrastructure• Use sbt-revolver + JRebel for fast dev turn- around
    79. 79. There is more ...
    80. 80. There is more ...• SprayJsonSupport, LiftJsonSupport, TwirlSupport, ScalateSupport
    81. 81. There is more ...• SprayJsonSupport, LiftJsonSupport, TwirlSupport, ScalateSupport• Asynchronous response push streaming
    82. 82. There is more ...• SprayJsonSupport, LiftJsonSupport, TwirlSupport, ScalateSupport• Asynchronous response push streaming• Testing spray routes
    83. 83. There is more ...• SprayJsonSupport, LiftJsonSupport, TwirlSupport, ScalateSupport• Asynchronous response push streaming• Testing spray routes• RESTful errors
    84. 84. There is more ...• SprayJsonSupport, LiftJsonSupport, TwirlSupport, ScalateSupport• Asynchronous response push streaming• Testing spray routes• RESTful errors• spray-client
    85. 85. There is more ...• SprayJsonSupport, LiftJsonSupport, TwirlSupport, ScalateSupport• Asynchronous response push streaming• Testing spray routes• RESTful errors• spray-client• spray-io
    86. 86. What’s next?
    87. 87. What’s next?• release 1.0 featuring improved and simplified API for Akka 2.0
    88. 88. What’s next?• release 1.0 featuring improved and simplified API for Akka 2.0• Better and deeper documentation (follow Akkas model of treating docs as code)
    89. 89. What’s next?• release 1.0 featuring improved and simplified API for Akka 2.0• Better and deeper documentation (follow Akkas model of treating docs as code)• Coming features: deeper REST support, monitoring, request throttling, ...
    90. 90. What’s next?• release 1.0 featuring improved and simplified API for Akka 2.0• Better and deeper documentation (follow Akkas model of treating docs as code)• Coming features: deeper REST support, monitoring, request throttling, ...• Possibly: websockets, SPDY
    91. 91. A few current sprayers ...
    92. 92. Getting started• Main site & documentation: https://github.com/spray/spray/wiki• Mailing list: http://groups.google.com/group/spray-user• Twitter: @spraycc
    93. 93. Thank you!
    94. 94. More
    95. 95. Route ExampleA simple spray route:val route: Route = path("order" / HexIntNumber) { id => get { completeWith { "Received GET request for order " + id } }~ put { completeWith { "Received PUT request for order " + id } } }
    96. 96. DirectivesDRYing up with the `|` operator:val route = path("order" / HexIntNumber) { id => (get | put) { ctx => ctx.complete("Received " + ctx.request.method + " request for order " + id) } }
    97. 97. DirectivesPulling out a custom directive:val getOrPut = get | putval route = path("order" / HexIntNumber) { id => getOrPut { ctx => ctx.complete("Received " + ctx.request.method + " request for order " + id) } }
    98. 98. DirectivesThe `&` operator as alternative to nesting:val getOrPut = get | putval route = (path("order" / HexIntNumber) & getOrPut) { id => ctx => ctx.complete("Received " + ctx.request.method + " request for order " + id) }
    99. 99. DirectivesPulling out once more:val orderGetOrPut = path("order" / HexIntNumber) & (get | put)val route = orderGetOrPut { id => ctx => ctx.complete("Received " + ctx.request.method + " request for order " + id) }
    100. 100. DirectivesOperators are type-safe:val orderPath = path("order" / IntNumber)
    101. 101. Directives Compiles?Operators are type-safe:val orderPath = path("order" / IntNumber)
    102. 102. Directives Compiles?Operators are type-safe:val orderPath = path("order" / IntNumber)val dir = orderPath | get
    103. 103. Directives Compiles?Operators are type-safe:val orderPath = path("order" / IntNumber)val dir = orderPath | get
    104. 104. Directives Compiles?Operators are type-safe:val orderPath = path("order" / IntNumber)val dir = orderPath | getval dir = orderPath | path("[^/]+".r / DoubleNumber)
    105. 105. Directives Compiles?Operators are type-safe:val orderPath = path("order" / IntNumber)val dir = orderPath | getval dir = orderPath | path("[^/]+".r / DoubleNumber)
    106. 106. Directives Compiles?Operators are type-safe:val orderPath = path("order" / IntNumber)val dir = orderPath | getval dir = orderPath | path("[^/]+".r / DoubleNumber)val dir = orderPath | parameter(order.as[Int])
    107. 107. Directives Compiles?Operators are type-safe:val orderPath = path("order" / IntNumber)val dir = orderPath | getval dir = orderPath | path("[^/]+".r / DoubleNumber)val dir = orderPath | parameter(order.as[Int])
    108. 108. Directives Compiles?Operators are type-safe:val orderPath = path("order" / IntNumber)val dir = orderPath | getval dir = orderPath | path("[^/]+".r / DoubleNumber)val dir = orderPath | parameter(order.as[Int])val order = orderPath & parameters(oem, expired ?)
    109. 109. Directives Compiles?Operators are type-safe:val orderPath = path("order" / IntNumber)val dir = orderPath | getval dir = orderPath | path("[^/]+".r / DoubleNumber)val dir = orderPath | parameter(order.as[Int])val order = orderPath & parameters(oem, expired ?)
    110. 110. Directives Compiles?Operators are type-safe:val orderPath = path("order" / IntNumber)val dir = orderPath | getval dir = orderPath | path("[^/]+".r / DoubleNumber)val dir = orderPath | parameter(order.as[Int])val order = orderPath & parameters(oem, expired ?)val route = order { (orderId, oem, expired) => ... // inner route}
    111. 111. Proxying with sprayCombining with spray-client to build a proxy:val conduit = new HttpConduit("target.example.com", 8080)lazy val proxyToTarget: Route = { ctx => ctx.complete { conduit.sendReceive { ctx.request.withHeadersTransformed { _.filter(_.name != "Host") } }.map { _.withHeadersTransformed { _.filter(_.name != "Date") } } }

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