@line/bot-sdk
Version:
Node.js SDK for LINE Messaging API
89 lines (75 loc) • 2.57 kB
text/typescript
import * as http from "node:http";
import { Buffer } from "node:buffer";
import { JSONParseError, SignatureValidationFailed } from "./exceptions.js";
import * as Types from "./types.js";
import validateSignature from "./validate-signature.js";
export type Request = http.IncomingMessage & { body: any };
export type Response = http.ServerResponse;
export type NextCallback = (err?: Error) => void;
export type Middleware = (
req: Request,
res: Response,
next: NextCallback,
) => void | Promise<void>;
function isValidBody(body?: any): body is string | Buffer {
return (body && typeof body === "string") || Buffer.isBuffer(body);
}
const readRequestBody = async (req: http.IncomingMessage): Promise<Buffer> => {
const chunks: Buffer[] = [];
for await (const chunk of req) {
chunks.push(chunk as Buffer);
}
return Buffer.concat(chunks);
};
export default function middleware(config: Types.MiddlewareConfig): Middleware {
if (!config.channelSecret) {
throw new Error("no channel secret");
}
const secret = config.channelSecret;
const _middleware: Middleware = async (req, res, next) => {
// header names are lower-cased
// https://nodejs.org/api/http.html#http_message_headers
const signature = req.headers[
Types.LINE_SIGNATURE_HTTP_HEADER_NAME
] as string;
if (!signature) {
next(new SignatureValidationFailed("no signature"));
return;
}
const body = await (async (): Promise<string | Buffer> => {
if (isValidBody((req as any).rawBody)) {
// rawBody is provided in Google Cloud Functions and others
return (req as any).rawBody;
} else if (isValidBody(req.body)) {
return req.body;
} else {
// body may not be parsed yet, parse it to a buffer
const rawBody = await readRequestBody(req);
if (isValidBody(rawBody)) {
return rawBody;
} else {
throw new JSONParseError("Invalid body", { raw: rawBody });
}
}
})();
if (!validateSignature(body, secret, signature)) {
next(
new SignatureValidationFailed("signature validation failed", {
signature,
}),
);
return;
}
const strBody = Buffer.isBuffer(body) ? body.toString() : body;
try {
req.body = JSON.parse(strBody);
next();
} catch (err) {
const { message } = err;
next(new JSONParseError(message, { raw: strBody }));
}
};
return (req, res, next): void => {
(<Promise<void>>_middleware(req, res, next)).catch(next);
};
}