From 66d7b69377ac4ec82fbc1f84cee3a1a00e4dae66 Mon Sep 17 00:00:00 2001
From: Johann150 <johann.galle@protonmail.com>
Date: Sun, 23 Oct 2022 13:34:37 +0200
Subject: [PATCH] server: refactor API handler and returning errors

This refactors the API handler to not use default exports, be async
instead of constructing a promise and modify how errors are returned.
---
 .../backend/src/server/api/api-handler.ts     | 61 +++++++++----------
 packages/backend/src/server/api/index.ts      |  2 +-
 2 files changed, 30 insertions(+), 33 deletions(-)

diff --git a/packages/backend/src/server/api/api-handler.ts b/packages/backend/src/server/api/api-handler.ts
index 956096367..f389ab8da 100644
--- a/packages/backend/src/server/api/api-handler.ts
+++ b/packages/backend/src/server/api/api-handler.ts
@@ -5,59 +5,56 @@ import authenticate, { AuthenticationError } from './authenticate.js';
 import call from './call.js';
 import { ApiError } from './error.js';
 
-export default (endpoint: IEndpoint, ctx: Koa.Context) => new Promise<void>((res) => {
+export async function handler(endpoint: IEndpoint, ctx: Koa.Context): Promise<void> {
 	const body = ctx.is('multipart/form-data')
 		? (ctx.request as any).body
 		: ctx.method === 'GET'
 			? ctx.query
 			: ctx.request.body;
 
-	const reply = (x?: any, y?: ApiError) => {
-		if (x == null) {
-			ctx.status = 204;
-		} else if (typeof x === 'number' && y) {
-			ctx.status = x;
-			ctx.body = {
-				error: {
-					message: y!.message,
-					code: y!.code,
-					id: y!.id,
-					kind: y!.kind,
-					...(y!.info ? { info: y!.info } : {}),
-				},
-			};
-		} else {
-			// 文字列を返す場合は、JSON.stringify通さないとJSONと認識されない
-			ctx.body = typeof x === 'string' ? JSON.stringify(x) : x;
+	const error = (e: ApiError): void => {
+		ctx.status = e.httpStatusCode ?? 500;
+		if (e.httpStatusCode === 401) {
+			ctx.response.set('WWW-Authenticate', 'Bearer');
 		}
-		res();
-	};
+		ctx.body = {
+			error: {
+				message: e!.message,
+				code: e!.code,
+				...(e!.info ? { info: e!.info } : {}),
+				endpoint: endpoint.name,
+			},
+		};
+	}
 
 	// Authentication
 	// for GET requests, do not even pass on the body parameter as it is considered unsafe
-	authenticate(ctx.headers.authorization, ctx.method === 'GET' ? null : body['i']).then(([user, app]) => {
+	await authenticate(ctx.headers.authorization, ctx.method === 'GET' ? null : body['i']).then(async ([user, app]) => {
 		// API invoking
-		call(endpoint.name, user, app, body, ctx).then((res: any) => {
+		await call(endpoint.name, user, app, body, ctx).then((res: any) => {
 			if (ctx.method === 'GET' && endpoint.meta.cacheSec && !body['i'] && !user) {
 				ctx.set('Cache-Control', `public, max-age=${endpoint.meta.cacheSec}`);
 			}
-			reply(res);
+			if (res == null) {
+				ctx.status = 204;
+			} else {
+				ctx.status = 200;
+				// If a string is returned, it must be passed through JSON.stringify to be recognized as JSON.
+				ctx.body = typeof res === 'string' ? JSON.stringify(res) : res;
+			}
 		}).catch((e: ApiError) => {
-			reply(e.httpStatusCode ? e.httpStatusCode : e.kind === 'client' ? 400 : 500, e);
+			error(e);
 		});
 	}).catch(e => {
 		if (e instanceof AuthenticationError) {
-			ctx.response.status = 403;
-			ctx.response.set('WWW-Authenticate', 'Bearer');
-			ctx.response.body = {
+			error({
 				message: 'Authentication failed: ' + e.message,
 				code: 'AUTHENTICATION_FAILED',
 				id: 'b0a7f5f8-dc2f-4171-b91f-de88ad238e14',
-				kind: 'client',
-			};
-			res();
+				httpStatusCode: 401,
+			});
 		} else {
-			reply(500, new ApiError());
+			error(new ApiError());
 		}
 	});
-});
+};
diff --git a/packages/backend/src/server/api/index.ts b/packages/backend/src/server/api/index.ts
index 83ece51f5..3f5708022 100644
--- a/packages/backend/src/server/api/index.ts
+++ b/packages/backend/src/server/api/index.ts
@@ -11,7 +11,7 @@ import cors from '@koa/cors';
 import { Instances, AccessTokens, Users } from '@/models/index.js';
 import config from '@/config/index.js';
 import endpoints from './endpoints.js';
-import handler from './api-handler.js';
+import { handler } from './api-handler.js';
 import signup from './private/signup.js';
 import signin from './private/signin.js';
 import signupPending from './private/signup-pending.js';