Handle pre-parsed string and buffer

Author: Hyunje Jun

lib/middleware.ts

@@ -26,23 +26,27 @@ export default function middleware(config: Line.Config & { channelSecret: string
       return;
     }
 
-    raw({ type: "*/*" })(
-      req as any,
-      res as any,
-      (() => {
-        if (!validateSignature(req.body, secret, signature)) {
-          next(new SignatureValidationFailed("signature validation failed", signature));
-          return;
-        }
-
-        const strBody = req.body.toString();
-        try {
-          req.body = JSON.parse(strBody);
-          next();
-        } catch (err) {
-          next(new JSONParseError(err.message, strBody));
-        }
-      }) as any,
-    );
+    const validate = (body: string | Buffer) => {
+      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) {
+        next(new JSONParseError(err.message, strBody));
+      }
+    };
+
+    if (typeof req.body === "string" || Buffer.isBuffer(req.body)) {
+      return validate(req.body);
+    }
+
+    // if body is not parsed yet, parse it to a buffer
+    raw({ type: "*/*" })(req as any, res as any, () => validate(req.body));
   };
 }

test/helpers/test-server.ts

@@ -10,6 +10,18 @@ function listen(port: number, middleware?: express.RequestHandler) {
   const app = express();
 
   if (middleware) {
+    app.use((req: express.Request, res, next) => {
+      if (req.path === "/mid-text") {
+        bodyParser.text({ type: "*/*" })(req, res, next);
+      } else if (req.path === "/mid-buffer") {
+        bodyParser.raw({ type: "*/*" })(req, res, next);
+      } else if (req.path === "/mid-json") {
+        bodyParser.json({ type: "*/*" })(req, res, next);
+      } else {
+        next();
+      }
+    });
+
     app.use(middleware);
   }
 

test/middleware.spec.ts

@@ -37,6 +37,24 @@ describe("middleware", () => {
       });
   });
 
+  it("succeed with pre-parsed string", () => {
+    const auth: any = { "X-Line-Signature": "qeDy61PbQK+aO97Bs8zjaFgYjQxFruGd13pfXPQoBRU=" };
+
+    return post(`${TEST_URL}/mid-text`, auth, { events: [webhook] })
+      .then((res: any) => {
+        deepEqual(res.body.events, [webhook]);
+      });
+  });
+
+  it("succeed with pre-parsed buffer", () => {
+    const auth: any = { "X-Line-Signature": "qeDy61PbQK+aO97Bs8zjaFgYjQxFruGd13pfXPQoBRU=" };
+
+    return post(`${TEST_URL}/mid-buffer`, auth, { events: [webhook] })
+      .then((res: any) => {
+        deepEqual(res.body.events, [webhook]);
+      });
+  });
+
   it("fails on wrong signature", () => {
     const auth: any = { "X-Line-Signature": "qeDy61PbQK+aO97Bs8zjbFgYjQxFruGd13pfXPQoBRU=" };