Expose wry navigation_handler via WindowBuilder closes #4080 (#5686)

Co-authored-by: silvanshade <silvanshade@users.noreply.github.com>
Co-authored-by: Lucas Nogueira <lucas@tauri.studio>

Author: silvanshade

.changes/core-navigation-handler.md

@@ -0,0 +1,5 @@
+---
+"tauri": minor
+---
+
+Added `Window::on_navigation`.

.changes/runtime-navigation-handler.md

@@ -0,0 +1,5 @@
+---
+"tauri-runtime": minor
+---
+
+Added `navigation_handler` field on `PendingWindow`.

.changes/wry-navigation-handler.md

@@ -0,0 +1,5 @@
+---
+"tauri-runtime-wry": minor
+---
+
+Implement the webview navigation handler.

core/tauri-runtime-wry/src/lib.rs

@@ -3061,6 +3061,11 @@ fn create_webview<T: UserEvent>(
     webview_builder = webview_builder
       .with_file_drop_handler(create_file_drop_handler(window_event_listeners.clone()));
   }
+  if let Some(navigation_handler) = pending.navigation_handler {
+    webview_builder = webview_builder.with_navigation_handler(move |url| {
+      Url::parse(&url).map(&navigation_handler).unwrap_or(true)
+    });
+  }
   if let Some(user_agent) = webview_attributes.user_agent {
     webview_builder = webview_builder.with_user_agent(&user_agent);
   }

core/tauri-runtime/src/window.rs

@@ -12,6 +12,7 @@ use crate::{
 };
 use serde::{Deserialize, Deserializer, Serialize};
 use tauri_utils::{config::WindowConfig, Theme};
+use url::Url;
 
 use std::{
   collections::{HashMap, HashSet},
@@ -232,6 +233,9 @@ pub struct PendingWindow<T: UserEvent, R: Runtime<T>> {
 
   /// A HashMap mapping JS event names with associated listener ids.
   pub js_event_listeners: Arc<Mutex<HashMap<JsEventListenerKey, HashSet<u64>>>>,
+
+  /// A handler to decide if incoming url is allowed to navigate.
+  pub navigation_handler: Option<Box<dyn Fn(Url) -> bool + Send>>,
 }
 
 pub fn is_label_valid(label: &str) -> bool {
@@ -271,6 +275,7 @@ impl<T: UserEvent, R: Runtime<T>> PendingWindow<T, R> {
         url: "tauri://localhost".to_string(),
         menu_ids: Arc::new(Mutex::new(menu_ids)),
         js_event_listeners: Default::default(),
+        navigation_handler: Default::default(),
       })
     }
   }
@@ -300,6 +305,7 @@ impl<T: UserEvent, R: Runtime<T>> PendingWindow<T, R> {
         url: "tauri://localhost".to_string(),
         menu_ids: Arc::new(Mutex::new(menu_ids)),
         js_event_listeners: Default::default(),
+        navigation_handler: Default::default(),
       })
     }
   }

core/tauri/src/window.rs

@@ -49,6 +49,7 @@ use std::{
 };
 
 pub(crate) type WebResourceRequestHandler = dyn Fn(&HttpRequest, &mut HttpResponse) + Send + Sync;
+pub(crate) type NavigationHandler = dyn Fn(Url) -> bool + Send;
 
 #[derive(Clone, Serialize)]
 struct WindowCreatedEvent {
@@ -109,6 +110,7 @@ pub struct WindowBuilder<'a, R: Runtime> {
   pub(crate) window_builder: <R::Dispatcher as Dispatch<EventLoopMessage>>::WindowBuilder,
   pub(crate) webview_attributes: WebviewAttributes,
   web_resource_request_handler: Option<Box<WebResourceRequestHandler>>,
+  navigation_handler: Option<Box<NavigationHandler>>,
 }
 
 impl<'a, R: Runtime> fmt::Debug for WindowBuilder<'a, R> {
@@ -182,6 +184,7 @@ impl<'a, R: Runtime> WindowBuilder<'a, R> {
       window_builder: <R::Dispatcher as Dispatch<EventLoopMessage>>::WindowBuilder::new(),
       webview_attributes: WebviewAttributes::new(url),
       web_resource_request_handler: None,
+      navigation_handler: None,
     }
   }
 
@@ -230,6 +233,33 @@ impl<'a, R: Runtime> WindowBuilder<'a, R> {
     self
   }
 
+  /// Defines a closure to be executed when the webview navigates to a URL. Returning `false` cancels the navigation.
+  ///
+  /// # Examples
+  ///
+  /// ```rust,no_run
+  /// use tauri::{
+  ///   utils::config::{Csp, CspDirectiveSources, WindowUrl},
+  ///   http::header::HeaderValue,
+  ///   window::WindowBuilder,
+  /// };
+  /// use std::collections::HashMap;
+  /// tauri::Builder::default()
+  ///   .setup(|app| {
+  ///     WindowBuilder::new(app, "core", WindowUrl::App("index.html".into()))
+  ///       .on_navigation(|url| {
+  ///         // allow the production URL or localhost on dev
+  ///         url.scheme() == "tauri" || (cfg!(dev) && url.host_str() == Some("localhost"))
+  ///       })
+  ///       .build()?;
+  ///     Ok(())
+  ///   });
+  /// ```
+  pub fn on_navigation<F: Fn(Url) -> bool + Send + 'static>(mut self, f: F) -> Self {
+    self.navigation_handler.replace(Box::new(f));
+    self
+  }
+
   /// Creates a new webview window.
   pub fn build(mut self) -> crate::Result<Window<R>> {
     let web_resource_request_handler = self.web_resource_request_handler.take();
@@ -239,12 +269,13 @@ impl<'a, R: Runtime> WindowBuilder<'a, R> {
       self.label.clone(),
     )?;
     let labels = self.manager.labels().into_iter().collect::<Vec<_>>();
-    let pending = self.manager.prepare_window(
+    let mut pending = self.manager.prepare_window(
       self.app_handle.clone(),
       pending,
       &labels,
       web_resource_request_handler,
     )?;
+    pending.navigation_handler = self.navigation_handler.take();
     let window = match &mut self.runtime {
       RuntimeOrDispatch::Runtime(runtime) => runtime.create_window(pending),
       RuntimeOrDispatch::RuntimeHandle(handle) => handle.create_window(pending),