Create ResourceUrlEncodingFilter for the reactive module [SPR-15012]

[spring-projects-issues]

Rossen Stoyanchev opened SPR-15012 and commented

Now that #19098 is resolved we can create a ResourceUrlEncoding filter that will encode static resource URLs.

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Affects: 5.0 M3

Issue Links:

• Reactive response URL-rewriting mechanism [SPR-14529] #19098 Reactive response URL-rewriting mechanism

[spring-projects-issues]

Rossen Stoyanchev commented

This solution for this has an impact on the fix for #19098 since the encoding of static resource URLs cannot be done with a synchronous signature (i.e. returning String). At present hte ResourceResolver and ResourceTransformer contracts are asynchronous (i.e. return Mono<String>).

[spring-projects-issues]

Rossen Stoyanchev commented

Resolving as Won't Fix.

The transformation of a static resource URL is more involved and requires consuming the resource content (e.g. in order to compute an MD5 hash) which may be remote or otherwise still requires the use of AsynchronousFileChannel to read without blocking.

For the time being we will not introduce a ResourceUrlEncoding that plugs into the encodeUrl mechanism of ServerHttpResponse and thus does not affect other use cases for URL encoding such as those related to Spring Security for example which do not need an asynchronous, non-blocking contract.

Instead for encoding links to static resources (e.g. with versions) tje ResourceUrlProvider should be used directly.