fix(express): signPayload API to handle stringified payload as req

Ticket: GNA-2162

Author: parvaparikh-30

modules/express/src/clientRoutes.ts

@@ -589,6 +589,15 @@ export async function handleV2OFCSignPayloadInExtSigningMode(
   }
 }
 
+const isJsonString = (str: any): boolean => {
+  try {
+    JSON.parse(str);
+    return true;
+  } catch {
+    return false;
+  }
+};
+
 export async function handleV2OFCSignPayload(req: express.Request): Promise<{ payload: string; signature: string }> {
   const walletId = req.body.walletId;
   const payload = req.body.payload;
@@ -630,7 +639,7 @@ export async function handleV2OFCSignPayload(req: express.Request): Promise<{ pa
 
   const walletPassphrase = bodyWalletPassphrase || getWalletPwFromEnv(wallet.id());
   const tradingAccount = wallet.toTradingAccount();
-  const stringifiedPayload = JSON.stringify(req.body.payload);
+  const stringifiedPayload = isJsonString(req.body.payload) ? req.body.payload : JSON.stringify(req.body.payload);
   const signature = await tradingAccount.signPayload({
     payload: stringifiedPayload,
     walletPassphrase,

modules/express/test/unit/clientRoutes/signPayload.ts

@@ -18,6 +18,7 @@ describe('Sign an arbitrary payload with trading account key', function () {
       },
     },
   };
+  const stringifiedPayload = JSON.stringify(payload);
   const signature = 'signedPayload123';
   const walletId = 'myWalletId';
 
@@ -41,7 +42,7 @@ describe('Sign an arbitrary payload with trading account key', function () {
     process.env['WALLET_myWalletId_PASSPHRASE'] = 'mypass';
   });
 
-  it('should return a signed payload', async function () {
+  it('should return a signed payload with type as object', async function () {
     // TODO(GO-1015): unskip test
     return;
 
@@ -60,6 +61,25 @@ describe('Sign an arbitrary payload with trading account key', function () {
     } as unknown as Request;
     await handleV2OFCSignPayload(req).should.be.resolvedWith(expectedResponse);
   });
+  it('should return a signed payload with type as json string', async function () {
+    // TODO(GO-1015): unskip test
+    return;
+
+    // eslint-disable-next-line no-unreachable
+    const expectedResponse = {
+      payload: stringifiedPayload,
+      signature,
+    };
+    const req = {
+      bitgo: bitGoStub,
+      body: {
+        payload: stringifiedPayload,
+        walletId,
+      },
+      query: {},
+    } as unknown as Request;
+    await handleV2OFCSignPayload(req).should.be.resolvedWith(expectedResponse);
+  });
 });
 
 describe('With the handler to sign an arbitrary payload in external signing mode', () => {