parses the email and forwards it to the appropriate recipient

inbound-parse.ts

import type {
  ExportedHandler,
} from "@cloudflare/workers-types";
import PostalMime, { type Email } from "postal-mime";

/**
 * This is the main entry point for the inbound email parsing service.
 * It is triggered when an email is received at the inbound email address.
 * It parses the email and forwards it to the appropriate recipient.
 */
const inboundParse: ExportedHandler = {
  async email(message) {
    const rawEmail = await streamToArrayBuffer(message.raw, message.rawSize);
    const parser = new PostalMime();
    const parsedEmail = await parser.parse(rawEmail);

    const headers = Object.fromEntries(message.headers.entries());
    const subject = message.headers.get("subject") || parsedEmail.subject;

    // Forward the email to another email address
    // await message.forward("email-address");

    // OR send it to another API / store in a database
    // fetch(...)

    return;
  },
};

async function streamToArrayBuffer(
  stream: ReadableStream<ArrayLike<number>>,
  streamSize: number,
) {
  const result = new Uint8Array(streamSize);
  let bytesRead = 0;
  const reader = stream.getReader();

  let isReading = true;

  while (isReading) {
    const { done, value } = await reader.read();
    if (done) {
      isReading = false;
      break;
    }
    result.set(value, bytesRead);
    bytesRead += value.length;
  }
  return result;
}

export default inboundParse;