web loading performance optimization with play 2.3 assets pipeline talk at Play Framework user group in Berlin: http://www.meetup.com/Play-Berlin-Brandenburg/events/203877602/

1. web performance
assets pipeline in Play 2.3

2. Speed is a feature
● Faster sites lead to better user
engagement
● Faster sites lead to better user retention
● Faster sites lead to higher conversions
Source:
http://chimera.labs.oreilly.com/books/1230000000545/ch01.html#SPEED_FEATURE

3. better performance
● less bytes
● less requests
● less latency

4. less bytes (1)
● gzip encoding
● doc:
https://www.playframework.com/document
ation/latest/GzipEncoding

5. less bytes (2)
● conditional requests
● Last-Modified and ETag headers provide
validation mechanisms

6. Last-Modified
● Server sets Last-Modified header
● Last-Modified: Tue, 15 Nov 1994 12:45:26 GMT
● Browser issues an If-Modified-Since
request header to validate the cached
document
● Server answers with 304 Not Modified
or 200 OK

7. Etag
● Server sets Etag header
● Etag: "15f0fff99ed5aae4edffdd6496d7131f"
● Browser issues an If-None-Match
request header to validate the cached
document
● Server answers with 304 Not Modified
or 200 OK

8. Conditional requests
● Last-modified: based on time
● Etag: based on content
● Since play 2.0.2

9. less requests
● Cache-Control switches on caching in
the browser
● avoid requests

10. Cache-Control
● Cache-Control:public
● Cache-Control:private
● Cache-Control:public, max-age=31536000
● Cache-Control:public
Expires: Mon, 25 Jun 2012 21:31:12 GMT

11. real world
● Caching strategies different from browser
to browser

12. perfect world
● in developement: always the last version
● in production:
– cache the assets as long as they are not
modified
– be sure that a browser does not use an
outdated cached asset

13. play 2.3
● pipelineStages := Seq(digest, gzip)
● in production mode
● content-based hash in the filename
● different content -> different fingerprint
● sets a very long cache

14. reduce latency
● Content delivery network (CDN)
● distributes content around globe
● location near from client
● request without cookie
● downside: one more DNS lookup

15. play 2.3
● webjars
● pipelineStages := Seq(rjs, digest, gzip)
● assets from http://cdn.jsdelivr.net/

16. under the cover
● assets pipeline managed with sbt-web
and plugins:
https://github.com/sbt/sbt-web
● not play specific
● versioned assets controller in play 2.3

17. Code
https://github.com/leanovate/moodly

18. web perf - more info
● High Performance Browser Networking
http://chimera.labs.oreilly.com/books/12
30000000545/index.html
● https://devcenter.heroku.com/articles/inc
reasing-application-performance-with-http
-cache-headers
● https://developers.google.com/web/fundam
entals/performance/optimizing-content-ef
ficiency/http-caching