Better error handling for URL parsing

lib/api.dart

@@ -710,7 +710,12 @@ class InvenTreeAPI {
 
     var client = createClient(true);
 
-    final uri = Uri.parse(_url);
+    Uri? uri = Uri.tryParse(_url);
+
+    if (uri == null) {
+      showServerError(L10().invalidHost, L10().invalidHostDetails);
+      return null;
+    }
 
     // Check for invalid host
     if (uri.host.isEmpty) {
@@ -718,8 +723,11 @@ class InvenTreeAPI {
       return null;
     }
 
+    HttpClientRequest? request;
+
+    try {
       // Open a connection
-    HttpClientRequest? request = await client.getUrl(uri)
+      request = await client.getUrl(uri)
           .timeout(Duration(seconds: 10))
           .catchError((error) {
         print("GET request returned error");
@@ -744,6 +752,26 @@ class InvenTreeAPI {
 
         return null;
       });
+    } catch (error) {
+      if (error is FormatException) {
+        showServerError(
+          L10().invalidHost,
+          L10().invalidHostDetails)
+        ;
+      } else if (error is SocketException) {
+        showServerError(
+            L10().connectionRefused,
+            error.toString()
+        );
+      } else {
+        showServerError(
+          L10().serverError,
+          error.toString()
+        );
+      }
+
+      return null;
+    }
 
     if (request == null) {
       return null;