RapidREST: Mail Library

A library for building a complete mail server on RapidREST — reachable entirely over HTTP/S — aiming for compatibility with MAPI over HTTP (Outlook desktop), Exchange ActiveSync (mobile clients), and a standard RapidREST REST API for webmail/other downstream clients. Integrates Contacts, Calendar (with external sharing and scheduling), Notes/Tasks, full-text search over mail/attachments, and pluggable SPAM/anti-virus scanning.

Internet mail transport (inbound/outbound SMTP) is intentionally out of scope for this library — it hands off to a dedicated MTA (Postfix recommended) via a narrow internal HTTP ingestion boundary. No client (Outlook/EAS/ webmail) ever speaks SMTP/IMAP/POP to this library directly.

Status

This library is under active development. Phase 1 (the core data model, the standard RapidREST CRUD API, mail ingestion/scanning/search), Phase 2 (Exchange ActiveSync), and Autodiscover are complete. MAPI over HTTP (Phase 3) has not been implemented yet.

Exchange ActiveSync support (@rapidrest/mail/eas) covers the pragmatic command subset a real mobile client (iOS Mail, Outlook mobile, Android/Samsung Mail) needs for day-to-day use: Provision, FolderSync, Sync (Email/Contacts/Calendar/Tasks), SendMail/SmartForward/SmartReply, ItemOperations, Ping, Search (GAL), MeetingResponse, and Settings. It authenticates with the same JWT the rest of this library's routes already use — no separate EAS-specific login flow — which means a real native device (rather than a test client that already has a token) needs an OAuth 2.0 Authorization Server role in front of it to obtain one; that piece is tracked as a follow-up in @rapidrest/auth, not this library.

Autodiscover support (@rapidrest/mail/autodiscover) lets a real client find this deployment's EAS server URL from just an email address — classic POX (POST /autodiscover/autodiscover.xml) and the modern JSON variant Microsoft calls "Autodiscover v2" (GET /autodiscover/autodiscover.json/v1.0/<email>?Protocol=ActiveSync). Both endpoints are intentionally unauthenticated, matching Autodiscover v2's own spec design: they reveal nothing but a deployment-wide EAS URL (not a secret) once the requested address is confirmed to belong to a real mailbox here — real mailbox access is still fully gated by the JWT-protected EAS/REST layer, unchanged from above. For a real device to find these endpoints at all, the deployment's DNS needs a CNAME record for autodiscover.<your-domain> (and, optionally, a _autodiscover._tcp SRV record) pointing at wherever this server is mounted — an ops/deployment task, not something this library configures.

Usage

Pick a persistence backend by importing the matching subpath — @rapidrest/mail/mongo or @rapidrest/mail/sql — alongside the protocol-agnostic root import:

import { MailboxRouteMongo, FolderRouteMongo, MessageRouteMongo } from "@rapidrest/mail/mongo";

Register a BlobStore, SearchProvider, SpamScanProvider, AvScanProvider, and MailTransport implementation with your application's dependency injection container before starting the server — see src/blob/BlobStore.ts, src/search/SearchProvider.ts, src/scan/SpamScanProvider.ts/AvScanProvider.ts, and src/transport/MailTransport.ts for the interfaces and their default implementations.

To also serve Exchange ActiveSync, mount EasRouteMongo/EasRouteSQL at the protocol's well-known path with a one-line subclass:

import { EasRouteMongo } from "@rapidrest/mail/mongo";
import { RouteDecorators } from "@rapidrest/service-core";
const { Route } = RouteDecorators;

@Route("/Microsoft-Server-ActiveSync")
export class MyEasRoute extends EasRouteMongo {}

To also serve Autodiscover, mount AutodiscoverRouteMongo/AutodiscoverRouteSQL with a one-line subclass supplying the EAS URL from above:

import { AutodiscoverRouteMongo } from "@rapidrest/mail/mongo";
import { RouteDecorators } from "@rapidrest/service-core";
const { Route } = RouteDecorators;

@Route("/autodiscover")
export class MyAutodiscoverRoute extends AutodiscoverRouteMongo {
    protected readonly easUrl = "https://mail.example.com/Microsoft-Server-ActiveSync";
}