Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Speaker Deck
PRO
Sign in
Sign up
for free
Two Scoops of Scala
Kārlis Lauva
April 09, 2014
Programming
0
83
Two Scoops of Scala
April tech talk at FullContact
Kārlis Lauva
April 09, 2014
Tweet
Share
More Decks by Kārlis Lauva
See All by Kārlis Lauva
karlis
0
45
karlis
1
59
karlis
0
43
karlis
0
65
karlis
4
160
Other Decks in Programming
See All in Programming
timeseriesfr
0
150
naototty
1
190
y__mattu
0
240
pco2699
0
110
ktgrstsh
1
240
xrdnk
0
180
hamakou108
4
540
manfredsteyer
PRO
1
140
kodetr
0
160
daipresents
0
360
kensukenakazawa
0
110
kentatada
0
130
Featured
See All Featured
holman
462
280k
geeforr
333
29k
kneath
220
15k
chriscoyier
498
130k
colly
188
14k
shpigford
166
19k
hatefulcrawdad
257
17k
maltzj
502
36k
jensimmons
208
10k
mongodb
23
3.9k
geoffreycrofte
27
1.1k
lara
172
9.8k
Transcript
Two scoops of Scala & Unfiltered April 2014 FullContact techTalk
@skazhy
Scala? • object oriented and functional programming language • Type
safe • Runs on JVM
Unfiltered? • A toolkit for HTTP in Scala • Really,
really modular • Works with Netty and Jetty • Built for meetup.com realtime API • Makes good use of Scala's idioms
Toolchain • SBT - Scala Build Tool • Best conventions
from Maven world • Iterative development in SBT shell
My setup • IntelliJ + SBT console(s) inside tmux •
IntelliJ 13 has SBT support baked in
Deployment • Works great with Jenkins & Asgard • Minimal
configuration tweaks needed (wait for the next slide)
• A tool for fetching templates for Scala projects •
g8 skazhy/unfiltered-netty-rx • All SBT plugins for deployment and IntelliJ are included Bootstrapping with giter8
Using opinionated RESTful frameworks for microservices?
None
Example time!
object MyPlan extends cycle.Plan with cycle.ThreadPool with ServerErrorResponse { def
intent = { case GET(Path("/")) => ResponseString("Hello!") case OPTIONS(_) => Created ~> Location("/foo") case _ => NotFound } } unfiltered.netty.Http(1337).handler(MyPlan).run()
An Intent is a partial function that pattern matches HTTP
requests
A Plan is a binding between intent and the underlying
interface
Pattern matching • Decomposing data structures to extract certain fields
or validate them • Really powerful in Scala • “routing” mechanism in Unfiltered
None
Match on request methods • Use builtins: GET(_) POST(_) PATCH(_)
• Or define your own: object SPACEJUMP extends Method("SPACEJUMP")
What happens under the hood? class Method(method: String) { def
unapply[T](req: HttpRequest[T]) = if (req.method.equalsIgnoreCase(method)) Some(req) else None } object POST extends Method("POST")
Match on request headers BasicAuth(username, password) UserAgent("Cobook")
...on URN Path("/foobar") Path(Seg("contactLists" :: "v2" :: listId :: Nil))
// Will extract /contactLists/v2/1234
...or query parameters object AccountIdParam extends Params.Extract("numericId", Params.first ~> Params.nonempty
~> Params.long) PATCH(Params(AccountIdParam(accountId))) // Will extract 1234 from PATCH /foo?numericId=1234
None
function composition!
Responses are composable case _ => Unauthorized ~> ResponseString("No pasaran")
~> ResponseHeader("WWW-Authenticate", "Basic realm=foo")
• HTTP requests are stateless • HTTP responses are side
effects
Async made easy case req @ GET(Path("/async")) => val futureOp
= asyncOperation futureOp.onSuccess { case result => req.respond(Ok ~> ResponseString(result)) } futureOp.onFailure { case _ => req.respond(InternalServerError) }
Unfiltered plays well with RxJava too
case req @ GET(Path("/reactive")) => observableOp.subscribe( result => req.respond(ResponseString(result)) _
=> req.respond(InternalServerError) )
What about testing?
• Separate library for testing with Specs2 • Mocking with
Mockito • Comes bundled with the giter8 template unfiltered-specs2
object OperationPostSpec extends Specification { "PATCH /foo" should { lazy
val r = Http(url((host \ "foo").PATCH)) lazy val response = r() "return HTTP 200" in { response.getResponseStatus mustEqual 200 } } }
Consider using Unfiltered when you... • need an async &
lightweight HTTP service • Have separate business logic • Want to leverage the λ-force
Questions?