org.springframework.web.servlet.resource

Class AppCacheManifestTransfomer

java.lang.Object

org.springframework.web.servlet.resource.AppCacheManifestTransfomer

All Implemented Interfaces:

ResourceTransformer

public class AppCacheManifestTransfomer
extends Object
implements ResourceTransformer

A ResourceTransformer implementation that helps handling resources within HTML5 AppCache manifests for HTML5 offline applications.

This transformer:

• modifies links to match the public URL paths that should be exposed to clients, using configured ResourceResolver strategies
• appends a comment in the manifest, containing a Hash (e.g. "# Hash: 9de0f09ed7caf84e885f1f0f11c7e326"), thus changing the content of the manifest in order to trigger an appcache reload in the browser.

All files that have the ".manifest" file extension, or the extension given in the constructor, will be transformed by this class. This hash is computed using the content of the appcache manifest and the content of the linked resources; so changing a resource linked in the manifest or the manifest itself should invalidate browser cache.

Since:

4.1

Author:

Brian Clozel

See Also:

HTML5 offline applications spec

Constructor Summary

Constructors

Constructor and Description
AppCacheManifestTransfomer() Create an AppCacheResourceTransformer that transforms files with extension ".manifest"
AppCacheManifestTransfomer(String fileExtension) Create an AppCacheResourceTransformer that transforms files with the extension given as a parameter.

Method Summary

Modifier and Type	Method and Description
Resource	transform(HttpServletRequest request, Resource resource, ResourceTransformerChain transformerChain) Transform the given resource.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AppCacheManifestTransfomer

public AppCacheManifestTransfomer()

Create an AppCacheResourceTransformer that transforms files with extension ".manifest"

AppCacheManifestTransfomer

public AppCacheManifestTransfomer(String fileExtension)

Create an AppCacheResourceTransformer that transforms files with the extension given as a parameter.

Method Detail

transform

public Resource transform(HttpServletRequest request,
                          Resource resource,
                          ResourceTransformerChain transformerChain)
                   throws IOException

Description copied from interface: ResourceTransformer

Transform the given resource.

Specified by:

transform in interface ResourceTransformer

Parameters:

request - the current request

resource - the resource to transform

transformerChain - the chain of remaining transformers to delegate to

Returns:

the transformed resource, never null

Throws:

IOException - if the transformation fails