A rewrite engine modifies the appearance of URLs in a web application. URL rewriting is used to make URLs more readable, search engine optimized, and to loosely couple the URL from the underlying implementation or framework. Rewrite is a new open source URL rewrite engine that provides a Java DSL for configuration and supports features like parameter extraction, validation, request actions, navigation handling, and response transformations through a pipeline. It aims to improve on existing solutions by providing a more extensible and typesafe configuration approach without framework dependencies. The rewrite-config-prettyfaces module can help migrate existing PrettyFaces applications to use Rewrite.

1. Christian Kaltepoth | ingenit GmbH & Co. KG
Beyond PrettyFaces
Einführung in Rewrite

2. URL-Rewriting

3. Wikipedia
A rewrite engine is software located in a
Web application framework running on a
Web server that modifies a web URL's
appearance.
This modification is called URL rewriting.
http://en.wikipedia.org/wiki/Rewrite_engine

4. Beispiel
http://www.onlineshop.de/b/ref=sa_m
enu_desk3?ie=UTF8&node=2193272340
http://www.onlineshop.de/elektronik

5. Sprechende RESTful URLs
http://www.javaserverfaces.org/news
http://jax.de/2013/sessions/
https://github.com/ocpsoft/rewrite/issues/87
http://stackoverflow.com/questions/tagged/jsf

6. Wozu das Ganze?

7. Vorteile
• Adressierbare Informationen
– Wo bin ich hier?
– "Vertrauen"
• Reload und Bookmarks
• Einfache HTML Links
– Lose Kopplung
• Technologieneutralität

8. SEO
• Keywords in URL
• Optimierung des Rankings
http://www.amazon.com/JavaServer-
Faces-2-0-Complete-
Reference/dp/0071625097

9. PrettyFaces
• JSF URL-Rewriting De-facto-Standard
• RESTful URLs
• Page Actions
• Einfache Rewrite Engine
• Dynamic Views
• Integration mit JSF Navigation

10. Warum Rewrite?

11. API Abhängigkeiten
Servlet-spezifisch
JSF-spezifisch
PrettyFaces

13. Einschränkungen
• Mapping nur via Request Path
• Eingeschränkte Konfiguration via XML
• Annotation API „verbesserungswürdig“
• Konvertierung nur eingeschränkt
möglich
• Nicht besonders erweiterbar

14. Der Neuanfang

15. Was ist Rewrite?

16. Key Features
• Servlet basiertes Rewriting auf Basis
einer Rule-Engine
• Framework Integration
– JSF, CDI, Spring, Shiro, etc.
• Konfiguration: Java DSL + Annotations
• Fokus auf Erweiterbarkeit
• Open Source (Apache 2.0)

17. Begriffe
• Configuration:
– Sortierte Liste
von Rules
• Rule:
– Conditions
– Operations
– Priority

18. Rewriting Types
Inbound
Outbound

19. Inbound
GET /faces/home.xhtml HTTP/1.1
Host: www.acme.com
Connection: keep-alive
[....]

20. Outbound
<a href="/faces/home.xhtml">
Getting started
</a>

21. Java DSL

22. Warum?
• Typensichere Konfiguration
• Code Assist durch IDE
• Erweiterbar
• Geführte Konfiguration
• „Plain Java“

23. Java DSL
public class RewriteConfig extends HttpConfigurationProvider {
@Override
public Configuration getConfiguration(ServletContext ctx) {
// Konfiguration
}
@Override
public int priority() {
return 10;
}
}

24. ConfigurationBuilder
return ConfigurationBuilder.begin()
// Variante 1
.addRule()
.when( /* condition */ )
.perform( /* operation */ )
// Variante 2
.addRule( /* rule */ )
;

25. Initial Redirect
http://www.acme.com/
http://www.acme.com/faces/home.xhtml
Redirect

26. Beispiel: Initial Redirect
.addRule()
.when(
Direction.isInbound().and(Path.matches("/"))
)
.perform(
Redirect.permanent("/faces/home.xhtml")
)

27. Der erste Rewrite
http://www.acme.com/faces/home.xhtml
http://www.acme.com/home

28. Der erste Rewrite
.addRule()
.when(Direction.isInbound().and(
Path.matches("/home")))
.perform(Forward.to("/faces/home.xhtml"))
.addRule()
.when(Direction.isOutbound().and(
Path.matches("/faces/home.xhtml")))
.perform(Substitute.with("/home"))

29. Einfacher: Joins
.addRule(
Join.path("/home")
.to("/faces/home.xhtml")
)

30. Parameter
/faces/products.xhtml?category=books
/products/books

31. JSF 2.0 View Parameter
<f:metadata>
<f:viewParam name="category"
value="#{productListPage.category}" />
</f:metadata>
@Named
@RequestScoped
public class ProductListPage {
private String category;
}

32. Join mit Parametern
.addRule(
Join.path("/products/{category}")
.to("/faces/products.xhtml")
)

33. Demo

34. Annotations?

35. Einfacher Join
@Named
@RequestScoped
@Join(path = "/home",
to = "/faces/home.xhtml")
public class HomePage {
/* your code */
}

36. Parameter
/faces/products.xhtml?category=books
/products/books

37. Mit View-Parametern
@Named
@RequestScoped
@Join(path = "/products/{category}",
to = "/faces/products.xhtml")
public class ProductListPage {
// <f:viewParam name=“category“ ...>
private String category;
/* ... */
}

38. Ohne View-Parameter
@Named
@RequestScoped
@Join(path = "/products/{category}",
to = "/faces/products.xhtml")
public class ProductListPage {
@Parameter
private String category;
/* ... */
}

39. Validierung
@Named
@RequestScoped
@Join(path = "/products/{category}",
to = "/faces/products.xhtml")
public class ProductListPage {
@Parameter
@Matches("[a-zA-Z-]+")
private String category;
/* ... */
}

40. JSF Validators
@Named
@RequestScoped
@Join(path = "/products/{category}",
to = "/faces/products.xhtml")
public class ProductListPage {
@Parameter
@Validate(with = CategoryValidator.class)
private String category;
/* ... */
}

41. Request Actions

42. Request Actions
@Named
@RequestScoped
@Join(path = "/home",
to = "/faces/home.xhtml")
public class HomePage {
@RequestAction
public void init() {
/* your code */
}
}

43. Ignore Postbacks
@Named
@ViewScoped
@Join(path = "/home",
to = "/faces/home.xhtml")
public class HomePage {
@RequestAction
@IgnorePostback
public void init() {
/* your code */
}
}

44. Deferral
@Named
@ViewScoped
@Join(path = "/home",
to = "/faces/home.xhtml")
public class HomePage {
@RequestAction
@Deferred(before = Phase.RENDER_RESPONSE)
public void prepareRender() {
/* your code */
}
}

45. Navigation

46. Navigation
<h:link outcome="/products.xhtml">
<f:param name="category" value="books"/>
Bücher
</h:link>
<a href="/products/books">
Bücher
</a>

47. Navigation
public class SomePage {
public String actionMethod() {
/* do something */
return "/products.xhtml?category=books" +
"&faces-redirect=true";
}
}

48. Navigation
public class SomePage {
public Navigate actionMethod() {
/* do something */
return Navigate.to(ProductListPage.class)
.with("category", "books");
}
}

49. Was kann Rewrite noch?

50. Content Delivery Networks
(CDN)

51. JSF Resources
<h:outputScript name="jquery.js" />
<script type="text/javascript"
src="/faces/javax.faces.resource/jquery.js" />
<script type="text/javascript"
src="http://dh8sm43.cloudfront.net/jquery.js" />
Erzeugt
Gewünscht

52. CDN URL Relocation
.addRule(
CDN.relocate("/faces/javax.faces.resource/jquery.js")
.to("http://dh8sm43.cloudfront.net/jquery.js")
)

53. Resource
Transformation

54. HTTP Response
Rewrite
Transformation
Pipeline

55. Usecases
• Minification
– JavaScript, CSS
• Compression
– GZIP, Deflate
• Rendering
– SASS, SCSS, Markdown, Textile, ...
• Custom Processing

56. JavaScript Minify
.addRule()
.when(
Direction.isInbound().and(Path.matches(
"/faces/javax.faces.resource/{*}.js"))
)
.perform(
Transform.with(Minify.js())
)

57. Rendering

58. Beispiel: Sass
$blue: #3bbfce;
$margin: 16px;
.content-navigation {
border-color: $blue;
color:
darken($blue, 9%);
}
.border {
padding: $margin / 2;
margin: $margin / 2;
border-color: $blue;
}
.content-navigation {
border-color: #3bbfce;
color: #2b9eab;
}
.border {
padding: 8px;
margin: 8px;
border-color: #3bbfce;
}

59. Beispiel: Sass
.addRule()
.when(
Direction.isInbound().and(
Path.matches("/styles/{*}.sass"))
)
.perform(
Response.setContentType("text/css").and(
Transform.with(Sass.compiler()))
);

60. Wie migriere ich meine
PrettyFaces Anwendung?

61. Rewrite PrettyFaces Module
<dependency>
<groupId>org.ocpsoft.rewrite</groupId>
<artifactId>rewrite-config-prettyfaces</artifactId>
<version>2.0.0.Final</version>
</dependency>
• Drop-In Replacement für PrettyFaces
• „Sanfte“ Migration

62. Thank you!
http://ocpsoft.org/rewrite/
Christian Kaltepoth
christian@kaltepoth.de
@chkal