v3.x: Does the Encoding Object's contentType allow whitespace around commas?

[handrews]

I expected it would (e.g. contentType: text/css, text/javascript, image/*) by analogy with the Accept header, while @ralfhandl read it more literally and expects only contentType: text/css,text/javascript,image/* would be allowed. I suppose it depends on your assumptions on the phrase "comma-separated list" which is all we say about it.

[handrews]

@ralfhandl is there any reason to restrict this? It's supposed to be analogous to Accept, which allows whitespace. Perhaps it is different in German but in English "comma-separated list" usually allows a space. You can see a clear example of this at the very end of §8.6 of RFC9110:

a recipient of a Content-Length header field value consisting of the same decimal value repeated as a comma-separated list (e.g, "Content-Length: 42, 42")

This usage is consistent throughout RFC9110, which I think is a pretty solid precedent. I think we should close this, or at most add a note emphasizing that whitespace is allowed. But really, I think 9110 is the governing precedent here.

[karenetheridge]

Personally I would not interpret "comma-separated list" as allowing whitespace if it was not explicitly stated. But indeed whitespace after commas is common in other places in RFC9110 so it would seem reasonable to allow it.

The best way to resolve this is to provide an ABNF for this field (using definitions established in RFC9110):

contentType = media-range *( "," OWS media-range )

[miqui]

Personally I would not interpret "comma-separated list" as allowing whitespace if it was not explicitly stated. But indeed whitespace after commas is common in other places in RFC9110 so it would seem reasonable to allow it.

Same here

[handrews]

I personally think that anything that is related to RFC9110 inherently uses its parsing rules because RFC9110 is a normative reference, but if someone feels compelled to write a PR for this, please go ahead. If no one is motivated to write a PR, let's close this.