@intx/mime

RFC 2822 message assembly and parsing. Builds multipart/signed messages with PGP detached signatures, parses inbound wire bytes back into structured parts, and owns the JMAP-shaped envelope the rest of the mail pipeline depends on.

Consumed by @intx/mail-memory (in-process transport), @intx/storage-isogit (mail audit log), and @intx/harness (sidecar mail-tool plumbing).

import {
  parseHeaderSection,
  parseMultipart,
  extractBoundary,
} from "@intx/mime";

const { headers, bodyOffset } = parseHeaderSection(rawMessageBytes);
const contentType = headers.get("content-type");
if (contentType === undefined) throw new Error("missing Content-Type");
const boundary = extractBoundary(contentType);
if (boundary === undefined) throw new Error("missing boundary parameter");
const parts = parseMultipart(rawMessageBytes.subarray(bodyOffset), boundary);

For outbound mail the builder layer is the entry point: createOutboundMessage produces a structured envelope, assembleSignedContent canonicalises the signed body, and assembleMessage joins the signed content with a detached signature from createDetachedSignatureFromProvider into wire bytes.