#mailchecker

Event-based POP3 mail client with message parser and local storage

mailchecker connects to a mailbox, fetches new messages, parses a chunk of messages and fires an event when new message is found. The module checks mailboxes once in an indicated period of time.

• The module adapts POP3 client to work with mailboxes.
• Processed message ids are stored in an knex-compatible database so emails don't get parsed twice.
• Message parsing is done by the Nodemailer mailparser module.

Usage

In order to start receiving messages from a mailbox you need to call the start method of the mailchecker module along with the mailbox credentials.

Each mailbox you pass will get checked with an indicated frequency, default is 10000ms. The number of new messages returned in each iteration is limited to 5 by default.

Events

The module emits two events: data and error. The data event is fired each time a new message is successfully parsed. The event returns a collection of new messages, parsed and ready for use.

Message object

Mails get parsed with the mailparser module. Parsed message object has the following properties

• headers – a Map object with lowercase header keys
• subject is the subject line (also available from the header mail.headers.get(‘subject’))
• from is an address object for the From: header
• to is an address object for the To: header
• cc is an address object for the Cc: header
• bcc is an address object for the Bcc: header (usually not present)
• date is a Date object for the Date: header
• messageId is the Message-ID value string
• inReplyTo is the In-Reply-To value string
• reply-to is an address object for the Cc: header
• references is an array of referenced Message-ID values
• html is the HTML body of the message. If the message included embedded images as cid: urls then these are all replaced with base64 formatted data: URIs
• text is the plaintext body of the message
• textAsHtml is the plaintext body of the message formatted as HTML
• attachments is an array of attachments.

Options

Options contain configurations for knex module as well as message chunk size and mailbox check period.

An example of options passed to the module:

        messageChunkSize: 5,
        checkPeriod: 5000,
        storage: {
            type: 'knex',
            tableName: 'processedmessage',
            db: {
                client: 'mysql',
                connection: {
                    database: 'mailchecker',
                    user: 'mailchecker',
                    password: 'mailchecker'
                },
                pool: {
                    min: 1,
                    max: 2
                },
                migrations: {
                    tableName: 'knex_migrations'
                },
                debug: false,
            }
        }
    }

Mailboxes

The start method accepts an array of objects containing mailbox credentials.

{
    "user": "yyy@yyy.yy",
    "password": "yyyyy",
    "host": "mail.xxxx.yy",
    "port": 110,
    "tls": true
}

Frequency of checking email

You may pass the frequency of checking mailbox in ms in the checkPeriod parameter.

Config

TBA

Basic usage

const mailchecker = require('./');
mailchecker.start([
        {
            user: 'yyy@yyy.yy',
            password: 'yyyyy',
            host: 'mail.xxxx.yy',
            port: 110,
            tls: true,
        }],
    {checkPeriod: 5000});
    
    
    mailchecker.on('data', (data) => {
        // process an array of messages
    });