# `Opsmaru.Incus.Gateway.Headers`
[🔗](https://github.com/upmaru/opsmaru-incus/blob/v0.1.0/lib/opsmaru/incus/gateway/headers.ex#L1)

Request/response header handling for the native relay.

Hop-by-hop fields (RFC 9110 section 7.6.1, plus any named by `connection`)
are removed in both directions. Caller credentials and proxy identity fields
(`authorization`, `proxy-authorization`, `cookie`, `forwarded`,
`x-forwarded-*`, `x-real-ip`) are never forwarded to the backend; the backend
only sees the gateway's own connection identity. `host` is set by the
backend connection. Every other end-to-end field, including duplicates and
`x-incus-*` fields, is forwarded unchanged.

# `request`

Filter caller headers for the backend and choose the request body framing.

Returns `{:ok, headers, body}` where body is `:none`, `{:length, n}` or
`:chunked`, or `{:error, failure}` before any backend contact.

# `response`

Validate and filter backend response headers (or trailers) for the caller.
Returns `{:ok, headers}` or `:error` for a field that could inject or
smuggle a response.

# `trailers`

Trailer fields that must never appear after a body.

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*Consult [api-reference.md](api-reference.md) for complete listing*