msg-parser-wasm

简体中文

A Rust-based parser for Microsoft Outlook .msg files, compiled to WebAssembly (WASM) for high-performance use in the browser.

Features

• Parse .msg files directly in the browser.
• Extract email metadata: Subject, Sender, Recipients (To/CC), Sent Time.
• Extract email body: Both Plain Text and HTML versions.
• Extract attachments: Filenames, Content-Types, Content-IDs (for inline images), and raw data.
• Support for multiple encodings (UTF-16, UTF-8, GBK).

Prerequisites

To build this project, you need:

• Rust
• wasm-pack

Build

You can build for different environments using the --out-dir flag:

Web (Direct Browser Usage)

For usage directly in a browser via <script type="module">.

wasm-pack build --target web --out-dir pkg/web

Bundler (Vite, Webpack, Rollup)

For usage with modern build tools. This is usually the default for npm packages.

wasm-pack build --target bundler --out-dir pkg/bundler

Usage

1. Web Target (No Bundler)

When using the web target, you must manually initialize the WASM module.

import init, { parse_msg_file } from './pkg/web/msg_parser_wasm.js';

async function run() {
    // Initialize the WASM module
    await init();

    const fileInput = document.getElementById('file-input');
    fileInput.addEventListener('change', async (e) => {
        const file = e.target.files[0];
        const uint8Array = new Uint8Array(await file.arrayBuffer());

        try {
            const emailData = parse_msg_file(uint8Array);
            console.log("Subject:", emailData.subject);
        } catch (err) {
            console.error("Parsing error:", err);
        }
    });
}
run();

2. Bundler Target (Vite/Webpack)

When using a bundler, the initialization is often handled automatically or through a simpler import.

import { parse_msg_file } from 'msg-parser-wasm'; // Or './pkg/bundler/msg_parser_wasm.js'

// Most bundlers allow direct usage if configured correctly
const emailData = parse_msg_file(uint8Array);

Data Structure

The parse_msg_file function returns a JavaScript object with the following structure:

interface MsgEmail {
    subject: string | null;
    sender_name: string | null;
    sender_email: string | null;
    recipients: string[];
    cc_recipients: string[];
    sent_time: string | null;
    body_text: string | null;
    body_html: string | null;
    attachments: Attachment[];
}

interface Attachment {
    filename: string;
    content_type: string | null;
    content_id: string | null;
    data: Uint8Array;
}

Optimization

The release build is optimized for size using:

• Link Time Optimization (LTO)
• opt-level = 'z' (optimize for size)

License

MIT