EmailFetcher.js

const Config = require("./config.json");

const Imaps = require('imap-simple');
const MailParser = require('mailparser');
const TurndownService = require('turndown');
const { parse } = require("path");
const createDOMPurify = require('dompurify');
const { JSDOM } = require('jsdom');
const _ = require('lodash');

function _u(u) { return u + "?rand=" + Math.random() + "-" + Date.now(); }

async function parseMessage(message) {
    const out = {};

    let all = _.find(message.parts, { "which": "" })

    const id = message.attributes.uid;
    const idHeader = "Imap-Id: " + id + "\r\n";

    const parsedBody = await MailParser.simpleParser(idHeader + all.body, {
        skipImageLinks: true,
        skipHtmlToText: false,
        skipTextToHtml: false,
        skipTextLinks: false
    });
    out.subject = parsedBody.subject;
    out.from = parsedBody.from.text;


    let body = parsedBody.html;
    if (!body) body = parsedBody.text;

    const window = new JSDOM('').window;
    const DOMPurify = createDOMPurify(window);
    body = DOMPurify.sanitize(body, {
        ALLOWED_TAGS: ['b', 'i', 'h1', 'h2', 'h3', 'a', 'img'],
        ALLOWED_ATTR: ['href', 'src']
    });

    body = new TurndownService().turndown(body);
    out.body_parts = body.match(/.{1,2000}/g)

    out.files = [];
    for (let i in parsedBody.attachments) {
        console.log("Found attachment", parsedBody.attachments[i].filename);
        files.push(
            {
                attachment: parsedBody.attachments[i].content,
                name: parsedBody.attachments[i].filename
            }
        );
    }

    return out;
}


// IMAP email fetch
async function emailFetch(discordClient) {
    let connection;
    const config = {
        imap: {
            user: Config.imapUser,
            password: Config.imapPassword,
            host: Config.imapHost,
            port: Config.imapPort,
            tls: true,
            authTimeout: 3000
        },
    };
    connection = await Imaps.connect(config);
    await connection.openBox("INBOX");

    const searchCriteria = ['UNSEEN'];
    const fetchOptions = {
        bodies: ['HEADER.FIELDS (SUBJECT FROM)', 'TEXT', ''],
        markSeen: true
    };
    connection.search(searchCriteria, fetchOptions).then(async (messages) => {

        console.log("Found", messages.length, "messages");
        for (let i in messages) {
            const message = await parseMessage(messages[i]);
            if (message.body_parts.length == 0) {
                console.error("message without body");
                continue;
            }
            if (message.subject.startsWith("MONITOR ") || message.subject.startsWith("ALERT SSH ")) {
                let monitorMessage;
                if (message.body_parts[0].startsWith("WARN:")) monitorMessage = ":x: **" + message.body_parts[0].trim() + "** " + Config.mentionOnImportant;
                else if (message.body_parts[0].startsWith("ALERT SSH ")) monitorMessage = ":warning:  " + message.body_parts[0].trim();
                else monitorMessage = ":white_check_mark: " + message.body_parts[0].trim();
                discordClient.channels.cache.get(Config.statusChannel).send(monitorMessage);
            } else {
                discordClient.channels.cache.get(Config.emailChannel).send(`**### EMAIL FROM ${message.from} ###**`);
                discordClient.channels.cache.get(Config.emailChannel).send(`
**Subject**: ${message.subject}
**Body**:
------------------------`);
                for (let i in message.body_parts) discordClient.channels.cache.get(Config.emailChannel).send(message.body_parts[i]);
                discordClient.channels.cache.get(Config.emailChannel).send("------------------------");
                discordClient.channels.cache.get(Config.emailChannel).send("**" + message.files.length + " Attachments**", message.files);
                discordClient.channels.cache.get(Config.emailChannel).send(`**### END ###**`);
                for (let i in message.files.files) message.files.files[i].attachment.release();
            }
        }
    }).catch(e => {
        console.error(e);
    }).finally(() => {
        connection.end();
    });
}


async function init(disbot){
    let mailFetchInterval = null;
    mailFetchInterval = setInterval(() => emailFetch(disbot), Config.mailCheckInterval * 1000);
    emailFetch(disbot);
    disbot.on('close', () => {
        clearInterval(mailFetchInterval);
    });   
}

module.exports={init:init};