Fix date format to use RFC 1123 format instead of culture-dependent format

Co-authored-by: waldekmastykarz <[email protected]>

Author: Copilot

DevProxy.Plugins/Behavior/GraphRandomErrorPlugin.cs

@@ -289,7 +289,7 @@ private void UpdateProxyResponse(ProxyRequestArgs e, HttpStatusCode errorStatus)
     {
         var session = e.Session;
         var requestId = Guid.NewGuid().ToString();
-        var requestDate = DateTime.Now.ToString(CultureInfo.CurrentCulture);
+        var requestDate = DateTime.Now.ToString("r", CultureInfo.InvariantCulture);
         var request = session.HttpClient.Request;
         var headers = ProxyUtils.BuildGraphResponseHeaders(request, requestId, requestDate);
         if (errorStatus == HttpStatusCode.TooManyRequests)
@@ -330,7 +330,7 @@ private void UpdateProxyBatchResponse(ProxyRequestArgs ev, GraphBatchResponsePay
 
         var session = ev.Session;
         var requestId = Guid.NewGuid().ToString();
-        var requestDate = DateTime.Now.ToString(CultureInfo.CurrentCulture);
+        var requestDate = DateTime.Now.ToString("r", CultureInfo.InvariantCulture);
         var request = session.HttpClient.Request;
         var headers = ProxyUtils.BuildGraphResponseHeaders(request, requestId, requestDate);
 

DevProxy.Plugins/Behavior/RateLimitingPlugin.cs

@@ -246,7 +246,7 @@ private void UpdateProxyResponse(ProxyHttpEventArgsBase e, HttpStatusCode errorS
             if (ProxyUtils.IsGraphRequest(request))
             {
                 var requestId = Guid.NewGuid().ToString();
-                var requestDate = DateTime.Now.ToString(CultureInfo.CurrentCulture);
+                var requestDate = DateTime.Now.ToString("r", CultureInfo.InvariantCulture);
                 headers.AddRange(ProxyUtils.BuildGraphResponseHeaders(request, requestId, requestDate));
 
                 body = JsonSerializer.Serialize(new GraphErrorResponseBody(

DevProxy.Plugins/Behavior/RetryAfterPlugin.cs

@@ -108,7 +108,7 @@ private static void UpdateProxyResponse(ProxyRequestArgs e, ThrottlingInfo throt
         if (ProxyUtils.IsGraphRequest(request))
         {
             var requestId = Guid.NewGuid().ToString();
-            var requestDate = DateTime.Now.ToString(CultureInfo.CurrentCulture);
+            var requestDate = DateTime.Now.ToString("r", CultureInfo.InvariantCulture);
             headers.AddRange(ProxyUtils.BuildGraphResponseHeaders(request, requestId, requestDate));
 
             body = JsonSerializer.Serialize(new GraphErrorResponseBody(

DevProxy.Plugins/Mocking/GraphMockResponsePlugin.cs

@@ -62,7 +62,7 @@ public override async Task BeforeRequestAsync(ProxyRequestArgs e, CancellationTo
         {
             GraphBatchResponsePayloadResponse? response = null;
             var requestId = Guid.NewGuid().ToString();
-            var requestDate = DateTime.Now.ToString(CultureInfo.CurrentCulture);
+            var requestDate = DateTime.Now.ToString("r", CultureInfo.InvariantCulture);
             var headers = ProxyUtils
                 .BuildGraphResponseHeaders(e.Session.HttpClient.Request, requestId, requestDate);
 
@@ -155,7 +155,7 @@ public override async Task BeforeRequestAsync(ProxyRequestArgs e, CancellationTo
         }
 
         var batchRequestId = Guid.NewGuid().ToString();
-        var batchRequestDate = DateTime.Now.ToString(CultureInfo.CurrentCulture);
+        var batchRequestDate = DateTime.Now.ToString("r", CultureInfo.InvariantCulture);
         var batchHeaders = ProxyUtils.BuildGraphResponseHeaders(e.Session.HttpClient.Request, batchRequestId, batchRequestDate);
         var batchResponse = new GraphBatchResponsePayload
         {

DevProxy.Plugins/Mocking/MockResponsePlugin.cs

@@ -348,7 +348,7 @@ private void ProcessMockResponseInternal(ProxyRequestArgs e, MockResponse matchi
     {
         string? body = null;
         var requestId = Guid.NewGuid().ToString();
-        var requestDate = DateTime.Now.ToString(CultureInfo.CurrentCulture);
+        var requestDate = DateTime.Now.ToString("r", CultureInfo.InvariantCulture);
         var headers = ProxyUtils.BuildGraphResponseHeaders(e.Session.HttpClient.Request, requestId, requestDate);
         var statusCode = HttpStatusCode.OK;
         if (matchingResponse.Response?.StatusCode is not null)