Fail requests with BAD_REQUEST if payload decoding fails

Author: bergundy

packages/test/src/test-nexus-handler.ts

@@ -390,6 +390,18 @@ test('start operation handler errors', async (t) => {
     at ServiceRegistry.start (/Users/bergundy/temporal/nexus-sdk-typescript/src/operation.ts)`
       );
     }
+    {
+      const res = await fetch(`http://localhost:${httpPort}/nexus/endpoints/${endpointId}/services/testService/op`, {
+        method: 'POST',
+        body: 'invalid',
+        headers: {
+          'Content-Type': 'application/json',
+        },
+      });
+      t.is(res.status, 400);
+      const { message } = await res.json() as { message: string };
+      t.is(message, 'Failed to deserialize input: SyntaxError: Unexpected token \'i\', "invalid" is not valid JSON');
+    }
   });
 });
 

packages/worker/src/nexus/index.ts

@@ -124,7 +124,15 @@ export class NexusHandler {
     options: nexus.StartOperationOptions
   ): Promise<coresdk.nexus.INexusTaskCompletion> {
     try {
-      const decoded = await decodeOptionalSingle(this.dataConverter.payloadCodecs, payload);
+      let decoded: Payload | undefined | null;
+      try {
+        decoded = await decodeOptionalSingle(this.dataConverter.payloadCodecs, payload);
+      } catch (err) {
+        throw new nexus.HandlerError({
+          type: 'BAD_REQUEST',
+          message: `Failed to decode payload: ${err}`,
+        });
+      }
       // Nexus headers have string values and Temporal Payloads have binary values. Instead of converting Payload
       // instances into Content instances, we embed the Payload in the serializer and pretend we are deserializing an
       // empty Content.
@@ -452,7 +460,14 @@ class PayloadSerializer implements nexus.Serializer {
     if (this.payload == null) {
       return undefined as T;
     }
+    try {
     return this.payloadConverter.fromPayload(this.payload);
+    } catch (err) {
+      throw new nexus.HandlerError({
+        type: 'BAD_REQUEST',
+        message: `Failed to deserialize input: ${err}`,
+      });
+    }
   }
 
   /** Not used in this path */