Pass filename hint to the ResourceDecoder

[filiphr]

Currently the ResourceDecoder uses the ByteArrayResource(byte[]) constructor. However, usually when working with Resource the Content-Disposition header can be used to send the filename of the resource. I think that in this case it would be helpful if that can be passed as the description.

[sdeleuze]

Thanks for your proposal.

ResourceDecoder lives in spring-core and has no knowledge of HTTP headers. Leveraging Content-Disposition header would require implementing and using a dedicated ResourceHttpMessageReader instead of the generic DecoderHttpMessageReader. Implementing your proposal would require additional infrastructure, so I would like to have more detail about your use case to evaluate if your need is common enough.

Also, if we decide to do something here, are we talking only about description or also about filename Resource property (currently not accessible from ByteArrayResource)?

[rstoyanchev]

FWIW there is similar logic in the converter equivalent:

spring-framework/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java

Lines 89 to 98 in 4fdfa42

	else if (Resource.class == clazz || ByteArrayResource.class.isAssignableFrom(clazz)) {
	byte[] body = StreamUtils.copyToByteArray(inputMessage.getBody());
	return new ByteArrayResource(body) {
	@Override
	@Nullable
	public String getFilename() {
	return inputMessage.getHeaders().getContentDisposition().getFilename();
	}
	};
	}

I suppose we could pass a filename hint without having the ResourceDecoder deal with an HTTP header.

[sdeleuze]

Feature parity between converters and codecs would be nice, so I add this improvement request in our 5.2 bucket.

@filiphr If you need that with 5.1, you can probably wrap the decoder and decorate the resource as a temporary workaround.

[filiphr]

You were faster than me to resolve everything 😄.

I suppose we could pass a filename hint without having the ResourceDecoder deal with an HTTP header.

I was indeed thinking about passing the filename in the hints, not making the ResourceDecoder aware about the HTTP headers, sorry about not being more specific, I thought the name of the issue would imply that.

Also, if we decide to do something here, are we talking only about description or also about filename Resource property (currently not accessible from ByteArrayResource)?

I was thinking about description as I saw that the filename is not exposed in the ByteArrayResource. However, pointing into the ResourceHttpMessageConverter indeed shows that one can set the filename properly.

I actually need the filename as that is more descriptive and something that I am looking for in the Resource.

Feature parity between converters and codecs would be nice, so I add this improvement request in our 5.2 bucket.

Thanks for adding it to the 5.2 bucket.

Just my 2 cents, you might want to support passing the filename to a ByteArrayResource in order not to need to provide something like in the ResourceHttpMessageConverter.

@filiphr If you need that with 5.1, you can probably wrap the decoder and decorate the resource as a temporary workaround.

I'll look into on our side to see what would be the best approach. Thanks for the hint