use of Link header

[aaronpk]

8: "The request MUST include at least one Link Header"

I am surprised by using Web Linking headers in a request. I cannot find a clear rule in RFC 5988 and have not checked other specifications yet that might do this. Is this allowed? I would guess that you at least need the "anchor" parameter, which sets the context to the resource URL. Has someone checked this, e.g., with Mark Nottingham?

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From #127 by @mkovatsc

[aaronpk]

I hadn't really considered whether it's "allowed" or not. PubSubHubbub has used this feature for years, so it's at least relatively widely implemented.

[aaronpk]

We discussed this on the call today. After looking into the two specs that WebSub references (RFC 7231 and RFC 5988), neither of those disallows the use of Link headers in a request. Additionally, the author (Mark Nottingham) has previously indicated that the Link header is intended to be allowed in HTTP requests, not just responses. As such, the group resolved to close this issue with no change, since the spec is very clear about the intent and there should be no confusion about what an implementation should do.

The request MUST include at least one Link Header [RFC5988] with rel=hub...

@mkovatsc please let us know if this addresses the issue for you.