feat: add document title changed handler, closes #804 (#825)

* feat: add document title changed handler, closes #804

* linux

* android

* macOS

* fix selector and change read

* use `of_object` instead

* fix macOS

Co-authored-by: Lucas Nogueira <lucas@tauri.studio>

.changes/document-title-changed-handler.md

@@ -0,0 +1,5 @@
+---
+"wry": "minor"
+---
+
+Add APIs to process webview document title change.

src/webview/android/binding.rs

@@ -13,7 +13,7 @@ use tao::platform::android::ndk_glue::jni::{
   JNIEnv,
 };
 
-use super::{IPC, REQUEST_HANDLER};
+use super::{IPC, REQUEST_HANDLER, TITLE_CHANGE_HANDLER};
 
 fn handle_request(env: JNIEnv, request: JObject) -> Result<jobject, JniError> {
   let mut request_builder = Request::builder();
@@ -167,3 +167,16 @@ pub unsafe fn ipc(env: JNIEnv, _: JClass, arg: JString) {
     Err(e) => log::warn!("Failed to parse JString: {}", e),
   }
 }
+
+#[allow(non_snake_case)]
+pub unsafe fn handleReceivedTitle(env: JNIEnv, _: JClass, _webview: JObject, title: JString) {
+  match env.get_string(title) {
+    Ok(title) => {
+      let title = title.to_string_lossy().to_string();
+      if let Some(w) = TITLE_CHANGE_HANDLER.get() {
+        (w.0)(&w.1, title)
+      }
+    }
+    Err(e) => log::warn!("Failed to parse JString: {}", e),
+  }
+}

src/webview/android/kotlin/RustWebChromeClient.kt

@@ -492,4 +492,13 @@ class RustWebChromeClient(appActivity: AppCompatActivity) : WebChromeClient() {
     val storageDir = activity.getExternalFilesDir(Environment.DIRECTORY_PICTURES)
     return File.createTempFile(imageFileName, ".jpg", storageDir)
   }
+
+  override fun onReceivedTitle(
+      view: WebView,
+      title: String
+  ) {
+    handleReceivedTitle(view, title)
+  }
+
+  private external fun handleReceivedTitle(webview: WebView, title: String);
 }

src/webview/android/mod.rs

@@ -52,11 +52,19 @@ macro_rules! android_binding {
       jobject
     );
     android_fn!($domain, $package, Ipc, ipc, [JString]);
+    android_fn!(
+      $domain,
+      $package,
+      RustWebChromeClient,
+      handleReceivedTitle,
+      [JObject, JString],
+    );
   };
 }
 
 pub static IPC: OnceCell<UnsafeIpc> = OnceCell::new();
 pub static REQUEST_HANDLER: OnceCell<UnsafeRequestHandler> = OnceCell::new();
+pub static TITLE_CHANGE_HANDLER: OnceCell<UnsafeTitleHandler> = OnceCell::new();
 
 pub struct UnsafeIpc(Box<dyn Fn(&Window, String)>, Rc<Window>);
 impl UnsafeIpc {
@@ -78,6 +86,15 @@ impl UnsafeRequestHandler {
 unsafe impl Send for UnsafeRequestHandler {}
 unsafe impl Sync for UnsafeRequestHandler {}
 
+pub struct UnsafeTitleHandler(Box<dyn Fn(&Window, String)>, Rc<Window>);
+impl UnsafeTitleHandler {
+  pub fn new(f: Box<dyn Fn(&Window, String)>, w: Rc<Window>) -> Self {
+    Self(f, w)
+  }
+}
+unsafe impl Send for UnsafeTitleHandler {}
+unsafe impl Sync for UnsafeTitleHandler {}
+
 pub unsafe fn setup(env: JNIEnv, looper: &ForeignLooper, activity: GlobalRef) {
   // we must create the WebChromeClient here because it calls `registerForActivityResult`,
   // which gives an `LifecycleOwners must call register before they are STARTED.` error when called outside the onCreate hook
@@ -224,6 +241,11 @@ impl InnerWebView {
       IPC.get_or_init(move || UnsafeIpc::new(Box::new(i), w));
     }
 
+    let w = window.clone();
+    if let Some(i) = attributes.document_title_changed_handler {
+      TITLE_CHANGE_HANDLER.get_or_init(move || UnsafeTitleHandler::new(i, w));
+    }
+
     Ok(Self { window })
   }
 

src/webview/mod.rs

@@ -224,6 +224,9 @@ pub struct WebViewAttributes {
   /// This configuration only impacts macOS.
   /// [Documentation](https://developer.apple.com/documentation/webkit/wkwebview/1414995-allowsbackforwardnavigationgestu).
   pub back_forward_navigation_gestures: bool,
+
+  /// Set a handler closure to process the change of the webview's document title.
+  pub document_title_changed_handler: Option<Box<dyn Fn(&Window, String)>>,
 }
 
 impl Default for WebViewAttributes {
@@ -251,6 +254,7 @@ impl Default for WebViewAttributes {
       zoom_hotkeys_enabled: false,
       accept_first_mouse: false,
       back_forward_navigation_gestures: false,
+      document_title_changed_handler: None,
     }
   }
 }
@@ -577,6 +581,15 @@ impl<'a> WebViewBuilder<'a> {
     self
   }
 
+  /// Set a handler closure to process the change of the webview's document title.
+  pub fn with_document_title_changed_handler(
+    mut self,
+    callback: impl Fn(&Window, String) + 'static,
+  ) -> Self {
+    self.webview.document_title_changed_handler = Some(Box::new(callback));
+    self
+  }
+
   /// Consume the builder and create the [`WebView`].
   ///
   /// Platform-specific behavior:

src/webview/webkitgtk/mod.rs

@@ -106,6 +106,17 @@ impl InnerWebView {
       close_window.gtk_window().close();
     });
 
+    // document title changed handler
+    if let Some(document_title_changed_handler) = attributes.document_title_changed_handler {
+      let w = window_rc.clone();
+      webview.connect_title_notify(move |webview| {
+        document_title_changed_handler(
+          &w,
+          webview.title().map(|t| t.to_string()).unwrap_or_default(),
+        )
+      });
+    }
+
     webview.add_events(
       EventMask::POINTER_MOTION_MASK
         | EventMask::BUTTON1_MOTION_MASK

src/webview/webview2/mod.rs

@@ -272,6 +272,27 @@ impl InnerWebView {
         .map_err(webview2_com::Error::WindowsError)?;
     }
 
+    // document title changed handler
+    if let Some(document_title_changed_handler) = attributes.document_title_changed_handler {
+      let window_c = window.clone();
+      unsafe {
+        webview
+          .add_DocumentTitleChanged(
+            &DocumentTitleChangedEventHandler::create(Box::new(move |webview, _| {
+              let mut title = PWSTR::null();
+              if let Some(webview) = webview {
+                webview.DocumentTitle(&mut title)?;
+                let title = take_pwstr(title);
+                document_title_changed_handler(&window_c, title);
+              }
+              Ok(())
+            })),
+            &mut token,
+          )
+          .map_err(webview2_com::Error::WindowsError)?;
+      }
+    }
+
     // Initialize scripts
     Self::add_script_to_execute_on_document_created(
       &webview,

src/webview/wkwebview/mod.rs

@@ -76,6 +76,7 @@ pub(crate) struct InnerWebView {
   // Note that if following functions signatures are changed in the future,
   // all functions pointer declarations in objc callbacks below all need to get updated.
   ipc_handler_ptr: *mut (Box<dyn Fn(&Window, String)>, Rc<Window>),
+  document_title_changed_handler: *mut (Box<dyn Fn(&Window, String)>, Rc<Window>),
   navigation_decide_policy_ptr: *mut Box<dyn Fn(String, bool) -> bool>,
   #[cfg(target_os = "macos")]
   file_drop_ptr: *mut (Box<dyn Fn(&Window, FileDropEvent) -> bool>, Rc<Window>),
@@ -378,6 +379,60 @@ impl InnerWebView {
         null_mut()
       };
 
+      // Document title changed handler
+      let document_title_changed_handler = if let Some(document_title_changed_handler) =
+        attributes.document_title_changed_handler
+      {
+        let cls = ClassDecl::new("DocumentTitleChangedDelegate", class!(NSObject));
+        let cls = match cls {
+          Some(mut cls) => {
+            cls.add_ivar::<*mut c_void>("function");
+            cls.add_method(
+              sel!(observeValueForKeyPath:ofObject:change:context:),
+              observe_value_for_key_path as extern "C" fn(&Object, Sel, id, id, id, id),
+            );
+            extern "C" fn observe_value_for_key_path(
+              this: &Object,
+              _sel: Sel,
+              key_path: id,
+              of_object: id,
+              _change: id,
+              _context: id,
+            ) {
+              let key = NSString(key_path);
+              if key.to_str() == "title" {
+                unsafe {
+                  let function = this.get_ivar::<*mut c_void>("function");
+                  if !function.is_null() {
+                    let function = &mut *(*function
+                      as *mut (Box<dyn for<'r> Fn(&'r Window, String)>, Rc<Window>));
+                    let title: id = msg_send![of_object, title];
+                    (function.0)(&function.1, NSString(title).to_str().to_string());
+                  }
+                }
+              }
+            }
+            cls.register()
+          }
+          None => class!(DocumentTitleChangedDelegate),
+        };
+
+        let handler: id = msg_send![cls, new];
+        let document_title_changed_handler =
+          Box::into_raw(Box::new((document_title_changed_handler, window.clone())));
+
+        (*handler).set_ivar(
+          "function",
+          document_title_changed_handler as *mut _ as *mut c_void,
+        );
+
+        let _: () = msg_send![webview, addObserver:handler forKeyPath:NSString::new("title") options:0x01 context:nil ];
+
+        document_title_changed_handler
+      } else {
+        null_mut()
+      };
+
       // Navigation handler
       extern "C" fn navigation_policy(this: &Object, _: Sel, _: id, action: id, handler: id) {
         unsafe {
@@ -684,6 +739,7 @@ impl InnerWebView {
         manager,
         pending_scripts,
         ipc_handler_ptr,
+        document_title_changed_handler,
         navigation_decide_policy_ptr,
         #[cfg(target_os = "macos")]
         file_drop_ptr,
@@ -935,28 +991,32 @@ impl Drop for InnerWebView {
     // We need to drop handler closures here
     unsafe {
       if !self.ipc_handler_ptr.is_null() {
-        let _ = Box::from_raw(self.ipc_handler_ptr);
+        drop(Box::from_raw(self.ipc_handler_ptr));
 
         let ipc = NSString::new(IPC_MESSAGE_HANDLER_NAME);
         let _: () = msg_send![self.manager, removeScriptMessageHandlerForName: ipc];
       }
 
+      if !self.document_title_changed_handler.is_null() {
+        drop(Box::from_raw(self.document_title_changed_handler));
+      }
+
       if !self.navigation_decide_policy_ptr.is_null() {
-        let _ = Box::from_raw(self.navigation_decide_policy_ptr);
+        drop(Box::from_raw(self.navigation_decide_policy_ptr));
       }
 
       #[cfg(target_os = "macos")]
       if !self.file_drop_ptr.is_null() {
-        let _ = Box::from_raw(self.file_drop_ptr);
+        drop(Box::from_raw(self.file_drop_ptr));
       }
 
       if !self.download_delegate.is_null() {
-        let _ = self.download_delegate.drop_in_place();
+        drop(self.download_delegate.drop_in_place());
       }
 
       for ptr in self.protocol_ptrs.iter() {
         if !ptr.is_null() {
-          let _ = Box::from_raw(*ptr);
+          drop(Box::from_raw(*ptr));
         }
       }