omnivore/packages/inbound-email-handler/src/index.ts

/* eslint-disable @typescript-eslint/no-unsafe-assignment */
/* eslint-disable @typescript-eslint/no-explicit-any */
/* eslint-disable @typescript-eslint/no-unsafe-argument */
/* eslint-disable @typescript-eslint/no-unused-vars */

import * as Sentry from '@sentry/serverless'
import parseHeaders from 'parse-headers'
import * as multipart from 'parse-multipart-data'
import {
  handleConfirmation,
  isConfirmationEmail,
  NewsletterHandler,
} from './newsletter'
import { PubSub } from '@google-cloud/pubsub'
import { handlePdfAttachment } from './pdf'
import { SubstackHandler } from './substack-handler'
import { AxiosHandler } from './axios-handler'
import { BloombergHandler } from './bloomberg-handler'
import { GolangHandler } from './golang-handler'

const NON_NEWSLETTER_EMAIL_TOPIC = 'nonNewsletterEmailReceived'
const pubsub = new PubSub()

const NEWSLETTER_HANDLERS = [
  new SubstackHandler(),
  new AxiosHandler(),
  new BloombergHandler(),
  new GolangHandler(),
]

export const getNewsletterHandler = (
  rawUrl: string,
  from: string
): NewsletterHandler | undefined => {
  return NEWSLETTER_HANDLERS.find((h) => {
    return h.isNewsletter(rawUrl, from)
  })
}

export const inboundEmailHandler = Sentry.GCPFunction.wrapHttpFunction(
  async (req, res) => {
    const parts = multipart.parse(req.body, 'xYzZY')
    const parsed: Record<string, string> = {}

    let pdfAttachment: Buffer | undefined
    let pdfAttachmentName: string | undefined

    for (const part of parts) {
      const { name, data, type, filename } = part
      if (name && data) {
        parsed[name] = data.toString()
      } else if (type === 'application/pdf' && data) {
        pdfAttachment = data
        pdfAttachmentName = filename
      } else {
        console.log('no data or name for ', part)
      }
    }

    const headers = parseHeaders(parsed.headers)
    console.log('parsed: ', parsed)
    console.log('headers: ', headers)

    try {
      const from = parsed.from.toString()
      const subject = parsed.subject
      const html = parsed.html
      const text = parsed.text

      const forwardedAddress = headers['x-forwarded-to']
      const recipientAddress = forwardedAddress
        ? forwardedAddress.toString()
        : parsed.to
      const rawUrl = headers['list-post'] ? headers['list-post'].toString() : ''

      // check if it is a forwarding confirmation email or newsletter
      const newsletterHandler = getNewsletterHandler(rawUrl, from)
      try {
        if (newsletterHandler) {
          console.log('handleNewsletter', from, recipientAddress)
          await newsletterHandler.handleNewsletter(
            recipientAddress,
            html,
            rawUrl,
            subject,
            from
          )
        } else {
          console.log('non-newsletter email from:', from, recipientAddress)

          if (isConfirmationEmail(from)) {
            console.log('handleConfirmation', from)
            await handleConfirmation(recipientAddress, subject)
          } else if (pdfAttachment) {
            console.log('handle PDF attachment', from, recipientAddress)
            await handlePdfAttachment(
              recipientAddress,
              pdfAttachmentName,
              pdfAttachment,
              subject
            )
          }

          // queue non-newsletter emails
          await pubsub.topic(NON_NEWSLETTER_EMAIL_TOPIC).publishMessage({
            json: {
              from: from,
              to: recipientAddress,
              subject: subject,
              html: html,
              text: text,
            },
          })
        }
      } catch (error) {
        console.log(
          'error handling emails, will forward.',
          from,
          recipientAddress,
          subject
        )
        // queue error emails
        await pubsub.topic(NON_NEWSLETTER_EMAIL_TOPIC).publishMessage({
          json: {
            from: from,
            to: recipientAddress,
            subject: subject,
            html: html,
            text: text,
          },
        })
      }

      res.send('ok')
    } catch (e) {
      console.log(e)
      res.send(e)
    }
  }
)