MboxReader

Reads email messages from a MBOX file. Output is an async generator where messages are yielded one by one.

MboxReader supports very large (multi gigabyte) mbox files as messages are processed asynchronously.

NB! mboxcl2 formatted mbox files are not supported as MboxReader assumes From-munging.

Usage

Free, AGPL-licensed version

First install the module from npm:

$ npm install mbox-reader

next import the mboxReader generator function into your script:

const { mboxReader } = require('mbox-reader');

MIT version

MIT-licensed version is available for Postal Systems subscribers.

First install the module from Postal Systems private registry:

$ npm install @postalsys/mbox-reader

next import the mboxReader generator function into your script:

const { mboxReader } = require('@postalsys/mbox-reader');

If you have already built your application using the free version of mbox-reader and do not want to modify require statements in your code, you can install the MIT-licensed version as an alias for "mbox-reader".

$ npm install mbox-reader@npm:@postalsys/mbox-reader

This way you can keep using the old module name

const { mboxReader } = require('mbox-reader');

Listing messages

mboxReader(readableStream, [options]) -> async generator

Where

• options is an optional options object
  • gz {Boolean} indicates if the input is a gz file (eg. gmail-takeout.mbox.gz). Default is false.

Generator yields objects with the following properties:

• returnPath Sender email address
• time Sending time as a Date object or false if date was not parseable
• content is a Buffer with the RFC822 formatted message
• flags an Array of IMAP compatible flags derived from Status or X-Status headers
• labels an Array of Gmail labels (ie. mailbox names) from X-Gmail-Labels headers
• headers a Map of headers where key is a lowercase header key and value is an array of header lines for this key (without the key prefix)

Example

Example reads mbox file from standard input and writes messages to console.

const { mboxReader } = require('mbox-reader');
 
for await (let message of mboxReader(process.stdin)) {
    console.log(message.returnPath);
    console.log(message.time);
    process.stdout.write(message.content);
}

License

© 2020 Andris Reinman

Licensed under GNU Affero General Public License v3.0 or later.

MIT-licensed version of mbox-reader is available for Postal Systems subscribers.