1 files changed, 87 insertions, 0 deletions
diff --git a/packages/backend/src/server/api/define.ts b/packages/backend/src/server/api/define.ts
new file mode 100644
index 0000000000..4bd8f95e31
--- /dev/null
+++ b/packages/backend/src/server/api/define.ts
@@ -0,0 +1,87 @@
+import * as fs from 'fs';
+import { ILocalUser } from '@/models/entities/user';
+import { IEndpointMeta } from './endpoints';
+import { ApiError } from './error';
+import { SchemaType } from '@/misc/schema';
+import { AccessToken } from '@/models/entities/access-token';
+
+type NonOptional<T> = T extends undefined ? never : T;
+
+type SimpleUserInfo = {
+	id: ILocalUser['id'];
+	host: ILocalUser['host'];
+	username: ILocalUser['username'];
+	uri: ILocalUser['uri'];
+	inbox: ILocalUser['inbox'];
+	sharedInbox: ILocalUser['sharedInbox'];
+	isAdmin: ILocalUser['isAdmin'];
+	isModerator: ILocalUser['isModerator'];
+	isSilenced: ILocalUser['isSilenced'];
+};
+
+type Params<T extends IEndpointMeta> = {
+	[P in keyof T['params']]: NonNullable<T['params']>[P]['transform'] extends Function
+		? ReturnType<NonNullable<T['params']>[P]['transform']>
+		: NonNullable<T['params']>[P]['default'] extends null | number | string
+			? NonOptional<ReturnType<NonNullable<T['params']>[P]['validator']['get']>[0]>
+			: ReturnType<NonNullable<T['params']>[P]['validator']['get']>[0];
+};
+
+export type Response = Record<string, any> | void;
+
+type executor<T extends IEndpointMeta> =
+	(params: Params<T>, user: T['requireCredential'] extends true ? SimpleUserInfo : SimpleUserInfo | null, token: AccessToken | null, file?: any, cleanup?: Function) =>
+		Promise<T['res'] extends undefined ? Response : SchemaType<NonNullable<T['res']>>>;
+
+export default function <T extends IEndpointMeta>(meta: T, cb: executor<T>)
+		: (params: any, user: T['requireCredential'] extends true ? SimpleUserInfo : SimpleUserInfo | null, token: AccessToken | null, file?: any) => Promise<any> {
+	return (params: any, user: T['requireCredential'] extends true ? SimpleUserInfo : SimpleUserInfo | null, token: AccessToken | null, file?: any) => {
+		function cleanup() {
+			fs.unlink(file.path, () => {});
+		}
+
+		if (meta.requireFile && file == null) return Promise.reject(new ApiError({
+			message: 'File required.',
+			code: 'FILE_REQUIRED',
+			id: '4267801e-70d1-416a-b011-4ee502885d8b',
+		}));
+
+		const [ps, pserr] = getParams(meta, params);
+		if (pserr) {
+			if (file) cleanup();
+			return Promise.reject(pserr);
+		}
+
+		return cb(ps, user, token, file, cleanup);
+	};
+}
+
+function getParams<T extends IEndpointMeta>(defs: T, params: any): [Params<T>, ApiError | null] {
+	if (defs.params == null) return [params, null];
+
+	const x: any = {};
+	let err: ApiError | null = null;
+	Object.entries(defs.params).some(([k, def]) => {
+		const [v, e] = def.validator.get(params[k]);
+		if (e) {
+			err = new ApiError({
+				message: 'Invalid param.',
+				code: 'INVALID_PARAM',
+				id: '3d81ceae-475f-4600-b2a8-2bc116157532',
+			}, {
+				param: k,
+				reason: e.message
+			});
+			return true;
+		} else {
+			if (v === undefined && def.hasOwnProperty('default')) {
+				x[k] = def.default;
+			} else {
+				x[k] = v;
+			}
+			if (def.transform) x[k] = def.transform(x[k]);
+			return false;
+		}
+	});
+	return [x, err];
+}