CODEWITHSUNDEEP
chttp2
Feruz Iskandarov
Feruz Iskandarov

Reputation: 68

What is the index number in static table for :protocol pseudo-header in http2?

I was making project which identifies websocket connections. As websocket connection way is changed in HTTP2, there was added a new pseudo-header ":protocol" as it is said in RFC8441. But I can't find an index number for this new pseudo-header in HPACK's static table.

I have tried googling but no information about it.

Upvotes: 3

Views: 112

Answers (1)

Barry Pollard
Barry Pollard

Reputation: 46040

You can’t add entries to the status table. First line in your HPACK link (emphasis mine):

The static table (see Section 2.3.1) consists in a predefined and unchangeable list of header fields.

And also from the introduction section:

The HPACK format is intentionally simple and inflexible. Both characteristics reduce the risk of interoperability or security issues due to implementation error. No extensibility mechanisms are defined; changes to the format are only possible by defining a complete replacement.

The header is therefore added to the dynamic HPACK table but with no fixed index number.

Even if it was assigned an index number in the static table it would be wrong to assume that was always used - different clients use the static and dynamic table differently.

Upvotes: 4

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