The document discusses the Spray framework for building REST/HTTP microservices in Scala. It provides an overview of Spray's features like routing directives and marshalling. It then gives examples of how to use Spray to build basic routing and marshalling, and provides two sample microservices for user registration and links that demonstrate integrating authentication, validation, and different HTTP methods.

1. Microservices in Spray
Łukasz Sowa @luksow
Jacek Głodek @jacekglodek

2. Spray
● Client- & server-side REST/HTTP libs
● Multiple layers – low-level to DSL
● Really fast (check out benchmarks!)
● „Acquired” by Typesafe
● Spray => akka-http
– Reactive streams
– New building block for Play
● Well-suited for REST microservices

3. Spray
● HttpRequest => HttpResponse
● Different levels of abstraction, focus: DSL
● Key concepts
– Routing directives
– Marshalling

4. Spray - routing
● Directives
– Transform, extract, filter, side-effecting
– Composable
– Concatanable

5. Spray - routing
● Useful directives
– path, pathPrefix
– get, post, put, delete, patch
– parameters
– formFields
– entity
– logRequestResponse
– complete (!)

6. Coding!
● Try out at least following combinations:
1) pathPrefix + path (with extracting)
2) get + parameters
3) post + formFields

7. Spray - marshalling
● Return anything that is marshalable
● String (OK(value))
● HttpEntity
● Option[T] (OK(T) vs. NotFound(T))
● Either[A, B] (OK(A) vs. OK(B))
● Future[T] (OK(T) – success vs. InternalServerError)
● Loads of predefined stuff, ex. JSON
● You can write your own!

8. Coding!
1) Try Option & Future marshallers
2) Use JSON marshaller to return JSON
3) Combine 1) & 2)
4) Use entity directive
5) Add validation
6) Time to create real microservices, yay!

9. Registration microservice
● POST /auth/account
● JSON { login: l, password: p, passwordConfirmation: pC }
● OK + { login: l, authToken: aT }
● BadRequest
● POST /auth/session
● Form login: l, password: p
● OK + { login: l, authToken: aT }
● Forbidden
● GET /auth/account (H: AuthToken: aT)
● OK + { login: l, authToken: aT, … }
● Forbidden

10. Links microservice
● Authenticate all the things! (Forbidden)
● POST /links/
● JSON { url: u, description: d }
● Save: ^ + date + author
● GET /links/:id
● JSON { url: u, description: d, date: dt, author: a }
● GET /links?limit=N&offset=M
● JSON { links: [url] }