Cloudflare Developers•7mo ago

Getting the body from a email-worker.

Hello there! I am in the process of transitioning to Cloudflare. Upon discovering that Cloudflare Workers support the ability to send emails to channels like Slack, I'm eager to implement this feature. I aim to send the body of the email to an external API. Is there a method to achieve this, and is there any pertinent information within the 'message' variable that I might have overlooked? Thanks in advance!

14 Replies

Jaren•7mo ago

You should be able to use the standard fetch api to send it to an api

Sven•7mo ago

I meant the body of the recieved email :)

Jaren•7mo ago

ah, misread. you would need to read the stream in the raw property of the message

Sven•7mo ago

Yea, only problem is I dont know how stream's work... I have read the docs but couldn't figure it out ;(

export default {
  async email(message, env, ctx) {
    switch (message.to) {
      case "EMAIL_CASE":
        await fetch("API_ENDPOINT", {
          method: 'POST',
          headers: {
            'Content-Type': 'application/json',
          },
          body: JSON.stringify({
            "icon": "📨",
            "title": message.headers.get('subject'),
            "body": readable.getReader({ mode: 'byob' }),
            "source": message.from,
          }),
        });
        break;
      default:
        message.reject("Unknown address");
    }
  }
}

export default {
  async email(message, env, ctx) {
    switch (message.to) {
      case "EMAIL_CASE":
        await fetch("API_ENDPOINT", {
          method: 'POST',
          headers: {
            'Content-Type': 'application/json',
          },
          body: JSON.stringify({
            "icon": "📨",
            "title": message.headers.get('subject'),
            "body": readable.getReader({ mode: 'byob' }),
            "source": message.from,
          }),
        });
        break;
      default:
        message.reject("Unknown address");
    }
  }
}

Chaika•7mo ago

can't stringify a stream would have to base64 it or escape it what I've done in the past is just passed along the metadata as headers

Jaren•7mo ago

What's stopping you from using it in a TextDecoder?

Chaika•7mo ago

It's an email, if his goal is to send it to slack or something he's really going to want to decode it first or it'd be a lot of useless junk

Jaren•7mo ago

couldn't you do this?

const textDecoder = new TextDecoder();
let result = "";
for await (let chunk of message.raw) {
    result += textDecoder.decode(chunk, { stream: true });
}

const textDecoder = new TextDecoder();
let result = "";
for await (let chunk of message.raw) {
    result += textDecoder.decode(chunk, { stream: true });
}

Chaika•7mo ago

sorry I only read the original post after, but yea if the intent is to send it to a webhook, use an email parser first to get the contents: here's an example to Discord: https://github.com/Tyler-OBrien/cloudflare-worker-emails-to-discord/blob/master/index.js a raw email looks something like this:

MIME-Version: 1.0
References: <CABxEEohuqZBoVpsyY4pOFMYixhU2bzfxgs9tRLbUoV2NJMqCJw@mail.gmail.com> 
<CAL5Lp9Xyo0mEQ6-c1yAQ+SuKXrT4Xu5y-7BnvnGS4RMjZOBJ=g@mail.gmail.com>
In-Reply-To: <CAL5Lp9Xyo0mEQ6-c1yAQ+SuKXrT4Xu5y-7BnvnGS4RMjZOBJ=g@mail.gmail.com>
From: Chris <c@sigparser.com>
Date: Wed, 9 Jan 2019 08:36:15 -0800
Message-ID: <CABxEEoizOPyCLkq4+FBGNaw7KC2TJDfTZF5dp8xD9aFjDQoL+Q@mail.gmail.com>
Subject: Re: food for thought
To: Paul <p@sigparser.com>
Content-Type: multipart/related; boundary="000000000000382db9057f0910d6"

--000000000000382db9057f0910d6
Content-Type: multipart/alternative; boundary="000000000000382db0057f0910d5"

--000000000000382db0057f0910d5
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Ok.  Just a thought.  Got it.

--000000000000382db0057f0910d5
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div><div dir=3D"auto">Ok.=C2=A0 Just a thought.=C2=A0 Got it. =C2=A0</div>=
</div><div><br><div class=3D"gmail_quote"><div dir=3D"ltr">On Wed, Jan 9, 2=

MIME-Version: 1.0
References: <CABxEEohuqZBoVpsyY4pOFMYixhU2bzfxgs9tRLbUoV2NJMqCJw@mail.gmail.com> 
<CAL5Lp9Xyo0mEQ6-c1yAQ+SuKXrT4Xu5y-7BnvnGS4RMjZOBJ=g@mail.gmail.com>
In-Reply-To: <CAL5Lp9Xyo0mEQ6-c1yAQ+SuKXrT4Xu5y-7BnvnGS4RMjZOBJ=g@mail.gmail.com>
From: Chris <c@sigparser.com>
Date: Wed, 9 Jan 2019 08:36:15 -0800
Message-ID: <CABxEEoizOPyCLkq4+FBGNaw7KC2TJDfTZF5dp8xD9aFjDQoL+Q@mail.gmail.com>
Subject: Re: food for thought
To: Paul <p@sigparser.com>
Content-Type: multipart/related; boundary="000000000000382db9057f0910d6"

--000000000000382db9057f0910d6
Content-Type: multipart/alternative; boundary="000000000000382db0057f0910d5"

--000000000000382db0057f0910d5
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Ok.  Just a thought.  Got it.

--000000000000382db0057f0910d5
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div><div dir=3D"auto">Ok.=C2=A0 Just a thought.=C2=A0 Got it. =C2=A0</div>=
</div><div><br><div class=3D"gmail_quote"><div dir=3D"ltr">On Wed, Jan 9, 2=

and that's a simple case. You'd want to run it through an email parser first to get the text/plain body, or the cleaned up text/html body if there is no text/plain

Sven•7mo ago

Thanks! (both of you)

Chaika•7mo ago

no problem! Yea you should be able to modify that repo to your needs, or you could just steal the parsing logic. It uses postal-mime and html-to-text, and the core of getting a useful contents to display is just:

   let rawEmail = new Response(message.raw);
    let arrayBuffer = await rawEmail.arrayBuffer();
    const parser = new PostalMime.default();
    const email = await parser.parse(arrayBuffer);
    let emailText = email.text;
    if (!emailText) {
      // If there is no text, try to get the text from the html
      emailText = convert(email.html);
    }

   let rawEmail = new Response(message.raw);
    let arrayBuffer = await rawEmail.arrayBuffer();
    const parser = new PostalMime.default();
    const email = await parser.parse(arrayBuffer);
    let emailText = email.text;
    if (!emailText) {
      // If there is no text, try to get the text from the html
      emailText = convert(email.html);
    }

Sven•7mo ago

That code will help me indeed with getting it to work faster :) Ty!

Andris Reinman•7mo ago

The postal-mime module API has changed, and it now includes built-in support for Cloudflare Email Workers. You can read about using it to parse emails from here: https://docs.emailengine.app/how-to-parse-emails-with-cloudflare-email-workers/

import PostalMime from 'postal-mime';
export default {
  async email(message, env, ctx) {
    const parser = new PostalMime();
    const email = await parser.parse(message.raw);
    // ... do something with the parsed email
  }
};

import PostalMime from 'postal-mime';
export default {
  async email(message, env, ctx) {
    const parser = new PostalMime();
    const email = await parser.parse(message.raw);
    // ... do something with the parsed email
  }
};

Chaika•7mo ago

ah that's really cool, you added that in today! Helps remove some of that boilerplate

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