How to conditionally fail requests based on request counts

Simulate a failed response on the first request and a successful one on subsequent attempts using shared state in Requestly.

$sharedState is only available in extension versions > v24.8.13 and desktop app versions > v1.7.1.

Steps to conditionally fail requests are:

1. Create a Modify Response Rule

   Open Requestly and create a new Modify Response rule.

2. Enable Dynamic JavaScript Modification

   Choose the Dynamic JavaScript option to write custom logic for the response.

3. Add JavaScript to Control Response Based on Request Count

   Use the following code to fail the first request and let others succeed:

   function modifyResponse(args) {
     const {
       method, url, response, responseType,
       requestHeaders, requestData, responseJSON
     } = args;
   
     // Get the current count or start from 0
     let count = $sharedState.count ?? 0;
     count++;
     $sharedState.count = count;
   
     // Succeed if it is not the first request
     if (count > 1) {
       return null;
     }
   
     // Allow all subsequent requests to succeed
     return response;
   }