Responses

Set headers before sending

Set headers first, then send the body. text and html accept null-terminated text and set a UTF-8 content type. json accepts already serialized JSON. send accepts an explicit byte length and is suitable for binary output. empty emits a status with no body.

import http
let health_response = fn (request:Http:Request*, response:Http:Response*) -> void {
    response.header("Cache-Control", "no-store")
    response.json(200, "{\"healthy\":true}")
}

Lifetimes and repeated sends

Keep response data alive

header borrows both strings until sending. Use string literals or keep allocated values alive until the send completes. send borrows body bytes for the duration of that call. A second send is ignored; headers added after sending are ignored too. Return immediately after handling an error to avoid ambiguous control flow.

import http
let require_token = fn (request:Http:Request*, response:Http:Response*) -> void {
    let token = request.header("X-Api-Token")
    if !token || token[0] == 0 {
        response.text(401, "token required")
        return
    }
    response.empty(204)
}

This checks presence only, not token validity. Application authentication must validate credentials. The writer generates Content-Length and closes the connection after the response. Do not add competing framing headers or insert unvalidated line breaks into header values.