The document discusses scaling web applications built with Scala. It covers several Scala web frameworks like Unfiltered, Spray, Lift and Roundup that allow building scalable and high performance web services using Scala. These frameworks leverage Scala language features and the Actor model to build non-blocking and asynchronous applications that can scale to large numbers of concurrent users.

1. Scalable language;
Scalable web
Timothy Perrett
ScalaDays 2012

2. Hello.

3. Hello.

5. Outline.

7. Scal•a•ble
Able to be used or produced in a range of
capabilities: it is scalable across a range of
systems.

9. Memory
Lane.

11. package example.java.sucks;
import java.io.*;
import javax.servlet.http.*;
import javax.servlet.*;
public class HelloServlet extends HttpServlet {
public void doGet (HttpServletRequest req,
HttpServletResponse res)
throws ServletException, IOException
{
PrintWriter out = res.getWriter();
out.println("Hello, world!");
out.close();
}
}

17. Vibrant Scala
Ecosystem.

19. Scaling Down.
Less is more.

21. Unfiltered.

23. type Intent[-A,-B] =
PartialFunction[
HttpRequest[A],
ResponseFunction[B]]

25. object Example extends Plan {
def intent = {
case GET(Path("ping")) =>
ResponseString("pong")
}
}

26. HttpRequest[A]
object Example extends Plan {
def intent = {
case GET(Path("ping")) =>
ResponseString("pong")
}
}

27. HttpRequest[A]
object Example extends Plan {
def intent = {
case GET(Path("ping")) =>
ResponseString("pong")
}
}
ResponseFunction[B]

28. Roundup

29. Roundup
๏ Leverage simple language
constructs.

30. Roundup
๏ Leverage simple language
constructs.
๏ Easy to learn.

31. Roundup
๏ Leverage simple language
constructs.
๏ Easy to learn.
๏ Easy to extend.

32. Roundup
๏ Leverage simple language
constructs.
๏ Easy to learn.
๏ Easy to extend.
๏ Micro-framework: less is more.

33. Roundup
๏ Leverage simple language
constructs.
๏ Easy to learn.
๏ Easy to extend.
๏ Micro-framework: less is more.
๏ Used by Meetup, RTM, Novus

35. Scaling Performance.
Building the next Facebook (obviously)

37. Spray.
(and blueeyes)

39. type Route =
RequestContext => Unit

41. path("foobar" / JavaUUID){ uuid =>
get {
_.completeWith {
// load Foo instance by uuid
}
}
}

42. path("foobar" / JavaUUID){ uuid =>
get {
_.completeWith {
// load Foo instance by uuid
}
}
}

43. path("foobar" / JavaUUID){ uuid =>
get {
_.completeWith {
// load Foo instance by uuid
}
}
}
implicit def foo[Foo : Marshaller]

45. case class Foo(whatever: String)
path("foobar" / JavaUUID){ uuid =>
put {
content(as[Foo]){ foo =>
...
}
}
}

47. Actors. Everywhere.

49. Detached
worker
HTTP Request HTTP Detached
worker
Service
Detached
worker

51. def receive = {
case HttpRequest(GET, "/", _, _, _) =>
...
}

52. Roundup

53. Roundup
๏ Totally actor-based

54. Roundup
๏ Totally actor-based
๏ Crazy-fast, non-blocking HTTP
Server

55. Roundup
๏ Totally actor-based
๏ Crazy-fast, non-blocking HTTP
Server
๏ Route definitions are just CPS

56. Roundup
๏ Totally actor-based
๏ Crazy-fast, non-blocking HTTP
Server
๏ Route definitions are just CPS
๏ Typeclass-based (un)marshalling

57. Roundup
๏ Totally actor-based
๏ Crazy-fast, non-blocking HTTP
Server
๏ Route definitions are just CPS
๏ Typeclass-based (un)marshalling
๏ Used by: VMWare, Zeebox, eBay

59. Scaling Features.
Real-time, secure applications.

61. Lift.

63. def foo =
"type=text" #> text(name, name = _) &
"type=submit" #> submit(println _)
<form lift="foo">
<p><input type="text" /></p>
<p><input type="submit" /></p>
</form>

64. NodeSeq => NodeSeq
def foo =
"type=text" #> text(name, name = _) &
"type=submit" #> submit(println _)
<form lift="foo">
<p><input type="text" /></p>
<p><input type="submit" /></p>
</form>

66. <form action="/" method="post">
<p><input type="text" name="F04FS5G5454" /></p>
<p><input type="submit" name="F0S324435" /></p>
</form>

68. NodeSeq.
(a.k.a XSS-safe templates)

70. Unparsed("<strong>ABC</
strong>")

71. Roundup

72. Roundup
๏ Secure by default

73. Roundup
๏ Secure by default
๏ Prevents common CSRF vulnerabilities

74. Roundup
๏ Secure by default
๏ Prevents common CSRF vulnerabilities
๏ XSS impossible without developer input

75. Roundup
๏ Secure by default
๏ Prevents common CSRF vulnerabilities
๏ XSS impossible without developer input
๏ Advocates server-controlled state

76. Roundup
๏ Secure by default
๏ Prevents common CSRF vulnerabilities
๏ XSS impossible without developer input
๏ Advocates server-controlled state
๏ Used by: 4sq, Stackmob, OpenStudy

78. What’s the
bottom line?

80. No.
Such.
Thing.

82. EOF
@timperrett
github.com/timperrett
timperrett.com