Files
sync-server-v2/source/services/router.ts

124 lines
4.5 KiB
TypeScript

import { z } from 'zod';
import { toExtendedJson } from '@xo-cash/utils';
import type { RequestHeaders, RouteDefinition, RouteModule } from '../routes/types.ts';
import { ApplicationError, UnauthorizedError } from '../errors/index.ts';
import { ApplicationRouteStream } from './route-stream.ts';
import type { BaseStream } from './stream/base-stream.ts';
import type { AuthSecp256k1 } from '../auth/auth.ts';
/** Canonical request produced by every transport adapter. */
export type ApplicationRequest = {
/** Exact application route name. */
path: string;
/** Transport-decoded application payload. */
body?: unknown;
/** Transport-normalized request headers, keyed by lowercase name. */
headers?: RequestHeaders;
/** Optional correlation ID supplied by a multiplexed transport. */
requestId?: string;
};
export type ApplicationRouterDependencies = {
/** Authentication service. */
auth: AuthSecp256k1;
};
const accountSchema = z
.object({
'x-public-key': z.string(),
'x-signature': z.string(),
'x-timestamp': z.coerce.number(),
})
.transform((data) => ({
publicKey: data['x-public-key'],
signature: data['x-signature'],
timestamp: data['x-timestamp'],
}));
/** Exact-match application routing shared by every wire transport. */
export class ApplicationRouter {
/** @param routes - Validated route table keyed by exact path. */
private constructor(
private readonly deps: ApplicationRouterDependencies,
private readonly routes: ReadonlyMap<string, RouteDefinition>,
) {}
/**
* Load and validate the complete route table before accepting traffic.
*
* @param routeModules - Route modules whose handlers will be registered.
* @returns A ready-to-dispatch router instance.
*/
static async create(deps: ApplicationRouterDependencies, routeModules: RouteModule[]): Promise<ApplicationRouter> {
const routes = new Map<string, RouteDefinition>();
// Collect routes from every module and reject duplicates at startup.
for (const routeModule of routeModules) {
for (const route of await routeModule.getRoutes()) {
ApplicationRouter.assertValidPath(route.url);
if (routes.has(route.url)) {
throw new Error(`Duplicate application route: ${route.url}`);
}
routes.set(route.url, route);
}
}
return new ApplicationRouter(deps, routes);
}
/**
* Execute one route using a request-scoped facade over the connection.
*
* @param request - Transport-normalized application request.
* @param connection - Shared connection stream for this transport session.
*/
async dispatch(request: ApplicationRequest, connection: BaseStream): Promise<void> {
// Authenticate the headers on the request.
const { publicKey, signature, timestamp } = accountSchema.parse(request.headers);
// Make sure the request signature is valid and hasnt been used before
await this.deps.auth.verifyUniqueRequest(signature);
// Ensure that the headers are present.
if (!publicKey || !signature || !timestamp) {
throw new UnauthorizedError('Missing authentication headers');
}
// Compile the signature payload as `Path:Timestamp:Body`
const signaturePayload = `${timestamp}:${request.path}:${toExtendedJson(request.body)}`;
// Verify the signature of the request.
const verified = await this.deps.auth.verifySignature(publicKey, signature, signaturePayload);
if (!verified) {
throw new UnauthorizedError('Invalid signature');
}
// Get the route from the routes map.
const route = this.routes.get(request.path);
if (!route) {
throw new ApplicationError(404, `No route found for ${request.path}`);
}
const stream = new ApplicationRouteStream(connection, request.body, request.path, request.requestId, request.headers);
await route.handler(stream);
}
/**
* Enforce the deliberately small exact-path routing grammar at startup.
*
* @param path - Candidate route path to validate.
*/
private static assertValidPath(path: string): void {
if (!path.startsWith('/') || path.length === 1 || path.includes(':') || path.includes('?') || path.includes('#')) {
throw new Error(`Invalid application route "${path}": routes must be exact paths beginning with /`);
}
}
}