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stack/apps/appservice/src/server.ts
jason.woltje c461380a4a
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feat(mosaic-as): agent registration + scoped/revocable tokens (US-007) (#541)
2026-06-16 01:10:44 +00:00

226 lines
8.4 KiB
TypeScript

import { createHmac, randomBytes, timingSafeEqual } from 'node:crypto';
import {
AgentTokenStore,
AppserviceIntent,
TransactionHandler,
validateBridgeMessage,
validateBridgeTyping,
validateProvisionRoom,
validateRegisterAgent,
validateRevokeAgent,
} from '@mosaicstack/appservice';
import type { AppserviceConfig, MatrixEvent } from '@mosaicstack/appservice';
export interface DaemonConfig extends AppserviceConfig {
/** Bearer tokens accepted on /bridge/v1/* (one per agent-comms host daemon). */
bridgeTokens: string[];
}
export interface DaemonRequest {
method: string;
/** URL path without query string. */
path: string;
searchParams: URLSearchParams;
authorizationHeader?: string;
body: unknown;
}
export interface DaemonResponse {
status: number;
body: Record<string, unknown>;
}
// Compare equal-length HMAC digests so neither content nor LENGTH of the
// stored secret is observable through timing.
const HMAC_KEY = randomBytes(32);
const digest = (value: string): Buffer => createHmac('sha256', HMAC_KEY).update(value).digest();
const safeEqual = (a: string, b: string): boolean => timingSafeEqual(digest(a), digest(b));
const TXN_PATH = /^\/_matrix\/app\/v1\/transactions\/([^/]+)$/;
/**
* Resolved identity for an authenticated /bridge/v1/* caller. Host principals
* (the agent-comms host daemons) are unrestricted; agent principals are scoped
* to a single virtual user and may only act as themselves.
*/
export type BridgePrincipal = { kind: 'host' } | { kind: 'agent'; agentUserId: string } | null;
/**
* HTTP-framework-agnostic request router for the mosaic-as daemon: the
* Application Service transactions endpoint (Synapse-facing) plus the
* internal bridge API v1 (agent-comms daemon-facing). main.ts binds this to
* node:http; tests drive it directly.
*/
export class AppserviceDaemon {
readonly intent: AppserviceIntent;
private readonly transactions: TransactionHandler;
private readonly agents: AgentTokenStore;
constructor(
private readonly cfg: DaemonConfig,
fetchImpl?: typeof fetch,
private readonly log: (line: string) => void = (line) => console.log(line),
) {
this.intent = new AppserviceIntent(cfg, fetchImpl);
this.agents = new AgentTokenStore(this.intent);
this.transactions = new TransactionHandler({
hsToken: cfg.hsToken,
onEvent: (event) => this.onEvent(event),
onError: (error, txnId) => this.log(`txn ${txnId} handler error: ${String(error)}`),
});
}
/** v1: the daemon only observes; room logic lives in the agent-comms daemons. */
private onEvent(event: MatrixEvent): void {
if (event.type === 'm.room.message') {
this.log(
`event ${event.event_id ?? '?'} in ${event.room_id ?? '?'} from ${event.sender ?? '?'}`,
);
}
}
/** Resolve the calling principal, or null when unauthorized. Fail-closed:
* host tokens win (timing-safe compare); otherwise a magt_* bearer is looked
* up in the agent token store; anything else is rejected. */
private async bridgeAuthorized(
authorizationHeader: string | undefined,
): Promise<BridgePrincipal> {
if (!authorizationHeader?.startsWith('Bearer ')) return null;
const presented = authorizationHeader.slice('Bearer '.length);
if (this.cfg.bridgeTokens.some((token) => safeEqual(presented, token))) {
return { kind: 'host' };
}
const agentUserId = await this.agents.verifyToken(presented);
if (agentUserId) return { kind: 'agent', agentUserId };
return null;
}
async handle(req: DaemonRequest): Promise<DaemonResponse> {
if (req.method === 'GET' && req.path === '/health') {
return { status: 200, body: { ok: true } };
}
const txnMatch = req.method === 'PUT' ? TXN_PATH.exec(req.path) : null;
if (txnMatch?.[1] !== undefined) {
return this.transactions.handle(txnMatch[1], req.body, {
authorizationHeader: req.authorizationHeader,
accessTokenParam: req.searchParams.get('access_token') ?? undefined,
});
}
if (req.path.startsWith('/bridge/v1/')) {
const principal = await this.bridgeAuthorized(req.authorizationHeader);
if (!principal) {
return { status: 403, body: { errcode: 'M_FORBIDDEN', error: 'bad bridge token' } };
}
try {
if (req.method === 'POST' && req.path === '/bridge/v1/agents') {
if (principal.kind !== 'host') {
return {
status: 403,
body: { errcode: 'M_FORBIDDEN', error: 'agents cannot register agents' },
};
}
validateRegisterAgent(req.body);
const { agentUserId, token } = await this.agents.register({
alias: req.body.alias,
host: req.body.host,
displayName: req.body.display_name,
});
this.log(`registered agent ${agentUserId}`);
return { status: 200, body: { agent_user_id: agentUserId, bridge_token: token } };
}
if (req.method === 'POST' && req.path === '/bridge/v1/agents/revoke') {
if (principal.kind !== 'host') {
return {
status: 403,
body: { errcode: 'M_FORBIDDEN', error: 'agents cannot revoke agents' },
};
}
validateRevokeAgent(req.body);
const revoked = await this.agents.revoke(req.body.agent_user_id);
this.log(`revoked ${revoked} token(s) for ${req.body.agent_user_id}`);
return { status: 200, body: { revoked } };
}
if (req.method === 'GET' && req.path === '/bridge/v1/agents') {
if (principal.kind !== 'host') {
return {
status: 403,
body: { errcode: 'M_FORBIDDEN', error: 'agents cannot list agents' },
};
}
const agents = await this.agents.list();
return { status: 200, body: { agents } };
}
if (req.method === 'POST' && req.path === '/bridge/v1/messages') {
validateBridgeMessage(req.body);
if (
principal.kind === 'agent' &&
this.intent.agentUserId(req.body.agent) !== principal.agentUserId
) {
return {
status: 403,
body: { errcode: 'M_FORBIDDEN', error: 'token not scoped to this agent' },
};
}
const eventId = await this.intent.sendAsAgent({
roomId: req.body.room_id,
agent: req.body.agent,
body: req.body.body,
threadRoot: req.body.thread_root,
msgtype: req.body.msgtype,
extraContent: req.body.extra_content,
});
return { status: 200, body: { event_id: eventId ?? null } };
}
if (req.method === 'POST' && req.path === '/bridge/v1/typing') {
validateBridgeTyping(req.body);
if (
principal.kind === 'agent' &&
this.intent.agentUserId(req.body.agent) !== principal.agentUserId
) {
return {
status: 403,
body: { errcode: 'M_FORBIDDEN', error: 'token not scoped to this agent' },
};
}
await this.intent.setTyping(req.body.room_id, req.body.agent, req.body.typing);
return { status: 200, body: {} };
}
if (req.method === 'POST' && req.path === '/bridge/v1/provision/rooms') {
validateProvisionRoom(req.body);
const result = await this.intent.createRoom({
name: req.body.name,
alias: req.body.alias,
topic: req.body.topic,
invite: req.body.invite,
spaceId: req.body.space_id,
});
this.log(
`provisioned room ${result.roomId} (${req.body.name}) space_linked=${result.spaceLinked}`,
);
return {
status: 200,
body: {
room_id: result.roomId,
space_linked: result.spaceLinked,
...(result.spaceError ? { space_error: result.spaceError } : {}),
},
};
}
} catch (error) {
const message = error instanceof Error ? error.message : String(error);
this.log(`bridge error ${req.method} ${req.path}: ${message}`);
return { status: 400, body: { error: message } };
}
// Explicit: never fall out of the authenticated bridge block, so future
// sub-paths cannot accidentally route around the auth guard above.
return { status: 405, body: { error: 'unsupported bridge method/path' } };
}
return { status: 404, body: { error: 'not found' } };
}
}