Request Filtering

Request Filtering

op_net::RequestFilter is the browser's native request-policy layer. It runs before the current document, stylesheet and image loading paths.

The initial syntax implements a deliberately small deterministic subset of common network filter rules:

• ||example.com^ host/subdomain blocking;
• * wildcard text patterns;
• @@ exception rules;
• resource options $document, $stylesheet/$css, $image, $script;
• per-site allowlisting.

The filter tracks checked/allowed/blocked request counters. Blocked loads return LoadError::BlockedRequest. Stylesheet and image failures remain nonfatal at the engine layer, so a blocked subresource behaves like another unavailable subresource rather than destroying the loaded document.

This is only the network-filter foundation. EasyList-scale parsing/indexing, domain options, third-party semantics, subscriptions, cosmetic filtering and a settings UI are not implemented yet. Rule matching must be profiled before large public lists are enabled; a linear scan is acceptable for the initial correctness slice but not the final design.