fix: request/response object validation (#709)

Author: AllanZhengYP

packages/protocol-http/src/httpRequest.ts

@@ -43,6 +43,7 @@ export class HttpRequest implements HttpMessage, Endpoint {
 
   static isInstance(request: unknown): request is HttpRequest {
     //determine if request is a valid httpRequest
+    if (!request) return false;
     const req: any = request;
     return (
       "method" in req &&

packages/protocol-http/src/httpResponse.ts

@@ -14,17 +14,19 @@ export class HttpResponse {
   public statusCode: number;
   public headers: HeaderBag;
   public body?: any;
-  private readonly isHttpResponse = true;
 
   constructor(options: HttpResponseOptions) {
     this.statusCode = options.statusCode;
     this.headers = options.headers || {};
     this.body = options.body;
   }
 
-  static isInstance(request: unknown): request is HttpResponse {
+  static isInstance(response: unknown): response is HttpResponse {
+    //determine if response is a valid HttpResponse
+    if (!response) return false;
+    const resp = response as any;
     return (
-      request !== undefined && (request as HttpResponse).isHttpResponse === true
+      typeof resp.statusCode === "number" && typeof resp.headers === "object"
     );
   }
 }