A pure Node.js library for parsing and building EML files, i.e. the e-mail message format described in RFC 822 (another link). EML is returned by the POP3 protocol and handled by many e-mail agents like Mozilla Thunderbird or Microsoft Outlook. An EML file consists of headers and body similar to the HTTP structure.

File extension: .eml
Mime type: message/rfc822

What does EML look like?

Date: Wed, 29 Jan 2014 11:10:06 +0100
To: "Foo Bar" <foo.bar@example.com>
From: Online Shop <no-reply@example.com>
Subject: Winter promotions
Content-Type: text/plain; charset=utf-8

Lorem ipsum...

Getting Started

Setup

npm install -g eml-format

Read EML file

var fs = require('fs');
var emlformat = require('eml-format');

var eml = fs.readFileSync("sample.eml", "utf-8");
emlformat.read(eml, function(error, data) {
  if (error) return console.log(error);
  fs.writeFileSync("sample.json", JSON.stringify(data, " ", 2));
  console.log(data);
});

Output structure

{
  "subject": "Winter promotions",
  "from": "Online Shop <no-reply@example.com>",
  "to": "\"Foo Bar\" <foo.bar@example.com>",
  "headers": {
    "Date": "Wed, 29 Jan 2014 11:10:06 +0100",
    "To": "\"Foo Bar\" <foo.bar@example.com>",
    "From": "Online Shop <no-reply@example.com>",
    "Subject": "Winter promotions",
    "Content-Type": "multipart/related; type=\"text/html\";\r\nboundary=\"b1_4afb675bba4c412783638afbee8e8c71\"",
    "MIME-Version": "1.0"
  },
  "html": "<!DOCTYPE html>\r\n<html lang=\"en\">\r\n<head>\r\n<title>Lorem ipsum</title>\r\n=09<meta name=\"description\" ...",
  "text": "Lorem ipsum dolor sit amet, consectetur adipiscing elit....",
  "attachments": [
    {
      "name": "nodejs.png",
      "mimeType": "image/png",
      "data": {
        "type": "Buffer",
        "data": [ 137, 80, 78, 71, ... ]
      }
    }
  ]
}

Command Line

A command line tool to extract an .eml file into a folder. The output directory will be populated with .txt and .html message and attachment files.

Usage:
  eml-unpack [options] [message.eml] [directory]

Options:
  --help       Print this message
  --verbose    Enable detailed logging
  --version    Print version number
  --json       Create parsed.json and manifest.json
  --no-unpack  Used with --json to skip unpacking

Examples:
  eml-unpack message.eml .
  eml-unpack --verbose sample.eml folder
  eml-unpack --json --no-unpack ./sample.eml ./folder

Reference

read(eml, [options], callback)

Parses EML file content and returns user-friendly object

Argument	Type	Description
eml	string or object	EML file content or object from 'parse'
options	object	Optional parameter, `{ headersOnly: true }` (`false` by default)
callback	function(error, data)	Callback function to be invoked when read is complete

parse(eml, [options], callback)

Parses EML file content and returns object-oriented representation of the content

Argument	Type	Description
eml	string	EML file content
options	object	Optional parameter, `{ headersOnly: true }` (`false` by default)
callback	function(error, data)	Callback function to be invoked when parse is complete

build(eml, callback)

Builds an EML message

Argument	Type	Description
data	object	E-mail data, see example
callback	function(error, eml)	Callback function to be invoked when build is complete

unpack(eml, directory, callback)

Unpacks EML message and attachments to a directory

Argument	Type	Description
eml	string or object	EML file content or object from 'parse'
directory	string	Folder name or directory path where to unpack
callback	function(error, data)	Callback function to be invoked when read is complete

Examples

Read headers only

var fs = require('fs');
var emlformat = require('eml-format');

var eml = fs.readFileSync("sample.eml", "utf-8");
emlformat.read(eml, { headersOnly: true }, function(error, data) {
  if (error) return console.log(error);
  fs.writeFileSync("headers.json", JSON.stringify(data, " ", 2));
  console.log(data);
  console.log("Done!");
});

Read the complete EML file

The parse function parses raw EML content into a JavaScript object for further processing.

var fs = require('fs');
var emlformat = require('eml-format');

var eml = fs.readFileSync("sample.eml", "utf-8");
emlformat.parse(eml, function(error, data) {
  if (error) return console.log(error);
  fs.writeFileSync("sample.json", JSON.stringify(data, " ", 2));
  console.log(data);
  console.log("Done!");
});

Or use read instead of parse. The read function decodes the base64, quote-printable, =?UTF-8?...?= encoded content and extracts plain text, html content and attachments. So this method is a little slower but more user friendly.

emlformat.read(eml, function(error, data) {
  if (error) return console.log(error);
  fs.writeFileSync("user-friendly.json", JSON.stringify(data, " ", 2));
  console.log(data);
  console.log("Done!");
});

Unpack files from an EML file

Extracts plain text, html content and attachments to a directory

var fs = require('fs');
var emlformat = require('eml-format');

var dir = "unpacked"; //Output directory
var eml = fs.readFileSync("sample.eml", "utf-8");
emlformat.unpack(eml, dir, function(error, data) {
  if (error) return console.log(error);
  console.log(data); //List of files
  console.log("Done!");
});

Create an EML file

var fs = require('fs');
var emlformat = require('eml-format');

var data = {
  from: "no-reply@bar.com",
  to: {
    name: "Foo Bar",
    email: "foo@bar.com"
  },
  subject: "Winter promotions",
  text: "Lorem ipsum...",
  html: '<html><head></head><body>Lorem ipsum...<br /><img src="nodejs.png" alt="" /></body></html>',
  attachments: [
    {
      name: "sample.txt",
      contentType: "text/plain; charset=utf-8",
      data: "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi eget elit turpis. Aliquam lorem nunc, dignissim in risus at, tempus aliquet justo..."
    },
    {
      name: "nodejs.png",
      contentType: "image/png",
      data: fs.readFileSync("nodejs.png"),
      inline: true
    }
  ]
};

var eml = fs.readFileSync("sample.eml", "utf-8");
emlformat.build(data, function(error, eml) {
  if (error) return console.log(error);
  fs.writeFileSync("build.eml", eml);
  console.log("Done!");
});

Multiple e-mail addresses

var data = {
  from: "no-reply@bar.com",
  to: [ 
		{ name: "Foo", email: "foo@example.com" },
		{ name: "Bar", email: "bar@example.com" }
	],
	cc: [
		{ name: "Foo Bar", email: "foo@bar.com" },
		{ email: "info@bar.com" }
	],
  subject: "Winter promotions",
  ...
};

Register a new mime type file extension

var emlformat = require('eml-format');
emlformat.fileExtensions["application/zip"] = ".zip";
emlformat.fileExtensions["application/octet-stream"] = ".bin";

Extract e-mail address and name

Plain text name

var emlformat = require('eml-format');
var data = emlformat.getEmailAddress('"Foo Bar" <foo@bar.com>');
//data.name == "Foo Bar";
//data.email == "foo@bar.com";

UTF-8 encoded name

var emlformat = require('eml-format');
var data = emlformat.getEmailAddress('=?UTF-8?Q?You=E2=80=99re=20Foo=20Bar?= <foo@bar.com>');
//data.name == "You’re Foo Bar";
//data.email == "foo@bar.com";

Decode "quoted-printable"

var emlformat = require('eml-format');
var message = emlformat.unquotePrintable("Join line 1=\r\n=20with line 2=0D=0A");

Decode "=?UTF-8?...?=" string

var emlformat = require('eml-format');
var message = emlformat.unquoteUTF8("=?UTF-8?B?V2hhdOKAmXMgeW91ciBvbmxpbmUgc2hvcHBpbmcgc3R5bGU/?=");

Decode other character set

var emlformat = require('eml-format');
var message = emlformat.unquoteString("=?ISO-8859-2?Q?Po=B9ta?=");

FAQs

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Is eml-format well maintained?

Last updated on 12 Oct 2019

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Install

eml-format

EML file format