Improve error handling and reporting (#190)

* Prevent duplicate reporting of errors to sentry

* Prevent error message upload on some server error codes

* Filter out some common errors we are not interested in

lib/api.dart

@@ -1018,6 +1018,12 @@ class InvenTreeAPI {
       if (_response.statusCode >= 500) {
         showStatusCodeError(url, _response.statusCode);
 
+        // Some server errors are not ones for us to worry about!
+        switch (_response.statusCode) {
+          case 502:   // Bad gateway
+          case 504:   // Gateway timeout
+            break;
+          default:    // Any other error code
             sentryReportMessage(
                 "Server error",
                 context: {
@@ -1029,7 +1035,8 @@ class InvenTreeAPI {
                   "responseData": response.data.toString(),
                 }
             );
-
+            break;
+        }
       } else {
 
         if (ignoreResponse) {

lib/inventree/model.dart

@@ -234,10 +234,23 @@ class InvenTreeModel {
     return {};
   }
 
+  /*
+   * Report error information to sentry, when a model operation fails.
+   */
   Future<void> reportModelError(String title, APIResponse response, {Map<String, String> context = const {}}) async {
 
     String dataString = response.data?.toString() ?? "null";
 
+    // If the response has "errorDetail" set, then the error has already been handled, and there is no need to continue
+    if (response.errorDetail.isNotEmpty) {
+      return;
+    }
+
+    // If the response status code indicates a server error, then this has already been reported
+    if (response.statusCode >= 500) {
+      return;
+    }
+
     if (dataString.length > 500) {
       dataString = dataString.substring(0, 500);
     }

lib/inventree/sentry.dart

@@ -145,6 +145,9 @@ Future<bool> sentryReportMessage(String message, {Map<String, String>? context})
 }
 
 
+/*
+ * Report an error message to sentry.io
+ */
 Future<void> sentryReportError(String source, dynamic error, dynamic stackTrace, {Map<String, String> context = const {}}) async {
 
   print("----- Sentry Intercepted error: $error -----");
@@ -166,6 +169,22 @@ Future<void> sentryReportError(String source, dynamic error, dynamic stackTrace,
     return;
   }
 
+  // Some errors are outside our control, and we do not want to "pollute" the uploaded data
+  if (source == "FlutterError.onError") {
+
+    String errorString = error.toString();
+
+    // Missing media file
+    if (errorString.contains("HttpException") && errorString.contains("404") && errorString.contains("/media/")) {
+      return;
+    }
+
+    // Local file system exception
+    if (errorString.contains("FileSystemException")) {
+      return;
+    }
+  }
+
   final server_info = getServerInfo();
   final app_info = await getAppInfo();
   final device_info = await getDeviceInfo();