Cloudflare - v1.3.0
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    Class RequestCorrelation

    The one header that carries a request id from one Worker to the next.

    Cloudflare gives every request that arrives from the internet a CF-Ray, and CloudflareRequestMetadata reads it as the request id — the id the dashboard's own logs are keyed by, so a line here and a line there can be joined without inventing anything.

    A subrequest gets no new one. When a Worker calls another over a Service Binding, or reaches an external API, the far end sees whatever headers the caller built and nothing the edge added. Without a header of its own the trail stops at each hop, and a failure three Workers deep cannot be walked back to the request that caused it.

    This is that header. The caller stamps its request id on the way out, the callee prefers an inbound value over minting a fresh one, and one id spans the whole fan-out.

    The value is attacker-controlled: anyone may send X-Request-Id. That is acceptable for joining log lines and unacceptable for anything else. It must never gate access, identify a caller, or stand in for a credential — the API key check in SecurityMiddleware is what decides who may call, and it reads none of this. The worst a forged value can do is put two unrelated requests under one id in a log query.

    const requestId = ctx.get('requestId')

    await env.NLP_WORKER.fetch('https://nlp/analyse', {
      method: 'POST',
      headers: { 'content-type': 'application/json', ...RequestCorrelation.of(requestId) },
      body
    })

    Bayu Dwiyan Satria

    1.2.0

    1.2.0

    Index
    constructor
    HEADER
    of
    HEADER: "x-request-id" = 'x-request-id'

    Name of the header carrying the request id between Workers.

    Lowercase because that is how the Workers runtime normalises header names, so a lookup and a comparison agree without either side calling toLowerCase first.

    • Builds the correlation header for an outbound call.

      Parameters

      • OptionalrequestId: string

        The id to propagate. Omit or pass a blank value to send nothing.

      Returns Record<string, string>

      The header as a spreadable object, empty when there is no id.

      Returns a plain object rather than a Headers, so it spreads into the headers a caller was already building instead of replacing them:

      headers: { 'content-type': 'application/json', ...RequestCorrelation.of(requestId) }

      An absent id yields an empty object. A hop with nothing to propagate should send no header at all rather than an empty one, which the far end would read as an id and correlate against.

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