Fix API requests that rely on cookie authentication failing in 22.1.7…

…4+ (Fix #268)

src/PrtgAPI/Request/PrtgRequestMessage.cs

@@ -22,6 +22,8 @@ internal class PrtgRequestMessage
 
         public Uri Uri { get; }
 
+        public IDictionary<string, string> Headers { get; } = new Dictionary<string, string>();
+
         /// <summary>
         /// Gets a parser capable of modifying the request response. If a custom parser external to this request message
         /// is specified for the API request, this parser is ignored.
@@ -77,6 +79,9 @@ private PrtgRequestMessage(ConnectionDetails connectionDetails, string function,
                 AddParameter(urlBuilder, Parameter.PassHash, connectionDetails.PassHash);
             }
 
+            if (parameters.Cookie)
+                Headers.Add("X-Requested-With", "XMLHttpRequest");
+
             Uri = new Uri(urlBuilder.ToString());
 
             Parser = parameters as IResponseParser;

src/PrtgAPI/Request/PrtgWebClient.cs

@@ -107,7 +107,17 @@ public Task<HttpResponseMessage> SendAsync(PrtgRequestMessage request, Cancellat
             //needs to be refactored to have the deserialization happen in a callback to ExecuteRequest
             //so that there is no problem wrapping the HttpResponseMessage up in a using for both
             //sync/async
-            return asyncClient.GetAsync(request.Uri, token);
+
+            var httpRequestMessage = new HttpRequestMessage
+            {
+                Method = HttpMethod.Get,
+                RequestUri = request.Uri
+            };
+
+            foreach (var header in request.Headers)
+                httpRequestMessage.Headers.Add(header.Key, header.Value);
+
+            return asyncClient.SendAsync(httpRequestMessage, token);
         }
     }
 }