This document discusses managing streams with Iteratee and Play framework. It provides an example of using Iteratee to handle an HTTP request body stream by consuming it chunk by chunk to calculate a hash, without loading the entire body into memory. Iteratee allows streaming data to be processed in a modular way without blocking threads. The document encourages using the coupon code "tokyoscala" for free hosting on Clever Cloud.

1. MANAGE
STREAMS WITH
ITERATEE AND
PLAY
FRAMEWORK
BY @WAXZCE
TOKYO SCALA USER GROUP

2. WHO AM I ?
CEO of Clever Cloud
PaaS provider
@waxzce on twitter
www.clever-cloud.com

3. WHY WE
NEED
ITERATEE ?
SO,

4. ITERATEE
HANDLING
STREAMS, LET’S
FIND EXAMPLE
IN FACTS

5. WHAT IS INSIDE AN
HTTP REQUEST ?
Verb
• The action
Resource
• The object of the action
Headers
• The context of the action
Body
• Optional
• The datas

6. IN MANY CASE THE REQUEST IS
MANIPULATE ALL FROM MEMORY

7. File upload for example
BUT SOMETIMES THE BODY PART IS
FAT

8. THERE IS 3 WAY TO RESOLVE THE
PROBLEM

9. PUT ALL IN MEMORY

10. CREATE TEMP FILE
Built in on play with

11. ACTING DIRECTLY ON
STREAM

12. HTTP
REQUEST IS
STREAM

13. SO WE WILL
JUST MANAGE
THE BODY
STREAM
JUST DO NOT REWRITE HTTP PARSER

14. CLASSIC JAVA STREAM
MANAGEMENT

15. CLASSIC JAVA STREAM
MANAGEMENT
• Low performances if not buffered
• Not modular
• Thread blocking
• Code is ugly

16. SCALA WAY
: ITERATEE

17. Like a recipe
Consume the data
ITERATEE : HOW TO MANAGE A STREAM

18. Produce the data
ENUMERATOR : DATA STREAM

19. Set of tools to do cool things with Iteratee and Enumerator
ENUMERATEE

20. SIMPLE ITERATEE
EXAMPLE

21. BODY
PARSERS
REQUEST HEADERS -> ITERATEE[ARRAY[BYTE],
EITHER[RESULT, ?]]

22. EXAMPLE
MANAGING
BODY

23. GET FILE AND
CALCULATE HASH FROM
CHUNK

24. NOW LIVE CODE !

25. GIFT FROM CLEVER
CLOUD
Use tokyoscala as coupon
code for free hosting 
On clever-cloud.com