feat: check if webview runtime is accessible when creating a webview

.changes/webview-runtime-check.md

@@ -0,0 +1,7 @@
+---
+"tauri": "patch:enhance"
+"tauri-runtime-wry": "patch:enhance"
+---
+
+Check if the webview runtime is accessible when creating a webview, returning an error if it doesn't.
+

crates/tauri-runtime-wry/Cargo.toml

@@ -76,3 +76,4 @@ objc-exception = []
 tracing = ["dep:tracing", "wry/tracing"]
 macos-proxy = ["wry/mac-proxy"]
 unstable = []
+common-controls-v6 = []

crates/tauri-runtime-wry/src/dialog/mod.rs

@@ -0,0 +1,16 @@
+// Copyright 2019-2024 Tauri Programme within The Commons Conservancy
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-License-Identifier: MIT
+
+#[cfg(windows)]
+mod windows;
+
+pub fn error<S: AsRef<str>>(err: S) {
+  #[cfg(windows)]
+  windows::error(err);
+
+  #[cfg(not(windows))]
+  {
+    unimplemented!("Error dialog is not implemented for this platform");
+  }
+}

crates/tauri-runtime-wry/src/dialog/windows.rs

@@ -0,0 +1,124 @@
+// Copyright 2019-2024 Tauri Programme within The Commons Conservancy
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-License-Identifier: MIT
+
+use windows::core::{w, HSTRING, PCWSTR};
+
+enum Level {
+  Error,
+  #[allow(unused)]
+  Warning,
+  #[allow(unused)]
+  Info,
+}
+
+pub fn error<S: AsRef<str>>(err: S) {
+  dialog_inner(err.as_ref(), Level::Error);
+}
+
+fn dialog_inner(err: &str, level: Level) {
+  let title = match level {
+    Level::Warning => w!("Warning"),
+    Level::Error => w!("Error"),
+    Level::Info => w!("Info"),
+  };
+
+  #[cfg(not(feature = "common-controls-v6"))]
+  {
+    use windows::Win32::UI::WindowsAndMessaging::*;
+
+    let err = remove_hyperlink(err);
+    let err = HSTRING::from(err);
+
+    unsafe {
+      MessageBoxW(
+        None,
+        err,
+        title,
+        match level {
+          Level::Warning => MB_ICONWARNING,
+          Level::Error => MB_ICONERROR,
+          Level::Info => MB_ICONINFORMATION,
+        },
+      )
+    };
+  }
+
+  #[cfg(feature = "common-controls-v6")]
+  {
+    use windows::core::HRESULT;
+    use windows::Win32::Foundation::*;
+    use windows::Win32::UI::Controls::*;
+    use windows::Win32::UI::Shell::*;
+    use windows::Win32::UI::WindowsAndMessaging::*;
+
+    extern "system" fn task_dialog_callback(
+      _hwnd: HWND,
+      msg: TASKDIALOG_NOTIFICATIONS,
+      _wparam: WPARAM,
+      lparam: LPARAM,
+      _data: isize,
+    ) -> HRESULT {
+      if msg == TDN_HYPERLINK_CLICKED {
+        let link = PCWSTR(lparam.0 as _);
+        let _ = unsafe { ShellExecuteW(None, None, link, None, None, SW_SHOWNORMAL) };
+      }
+
+      S_OK
+    }
+
+    let err = HSTRING::from(err);
+    let err = PCWSTR(err.as_ptr());
+
+    let task_dialog_config = TASKDIALOGCONFIG {
+      cbSize: std::mem::size_of::<TASKDIALOGCONFIG>() as u32,
+      dwFlags: TDF_ALLOW_DIALOG_CANCELLATION | TDF_ENABLE_HYPERLINKS,
+      pszWindowTitle: title,
+      pszContent: err,
+      Anonymous1: TASKDIALOGCONFIG_0 {
+        pszMainIcon: match level {
+          Level::Warning => TD_WARNING_ICON,
+          Level::Error => TD_ERROR_ICON,
+          Level::Info => TD_INFORMATION_ICON,
+        },
+      },
+      dwCommonButtons: TDCBF_OK_BUTTON,
+      pfCallback: Some(task_dialog_callback),
+      ..Default::default()
+    };
+
+    let _ = unsafe { TaskDialogIndirect(&task_dialog_config, None, None, None) };
+  }
+}
+
+#[cfg(not(feature = "common-controls-v6"))]
+fn remove_hyperlink(str: &str) -> String {
+  let mut result = String::new();
+  let mut in_hyperlink = false;
+
+  for c in str.chars() {
+    if c == '<' {
+      in_hyperlink = true;
+    } else if c == '>' {
+      in_hyperlink = false;
+    } else if !in_hyperlink {
+      result.push(c);
+    }
+  }
+
+  result
+}
+
+#[cfg(test)]
+#[cfg(not(feature = "common-controls-v6"))]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn test_remove_hyperlink() {
+    let input = "This is a <A href=\"some link\">test</A> string.";
+    let expected = "This is a test string.";
+    let result = remove_hyperlink(input);
+    assert_eq!(result, expected);
+  }
+}

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

@@ -130,6 +130,8 @@ use std::{
 pub type WebviewId = u32;
 type IpcHandler = dyn Fn(Request<String>) + 'static;
 
+#[cfg(not(debug_assertions))]
+mod dialog;
 mod monitor;
 #[cfg(any(
   windows,
@@ -248,6 +250,7 @@ pub struct Context<T: UserEvent> {
   next_webview_id: Arc<AtomicU32>,
   next_window_event_id: Arc<AtomicU32>,
   next_webview_event_id: Arc<AtomicU32>,
+  webview_runtime_installed: bool,
 }
 
 impl<T: UserEvent> Context<T> {
@@ -2712,6 +2715,7 @@ impl<T: UserEvent> Wry<T> {
       next_webview_id: Default::default(),
       next_window_event_id: Default::default(),
       next_webview_event_id: Default::default(),
+      webview_runtime_installed: wry::webview_version().is_ok(),
     };
 
     Ok(Self {
@@ -4421,6 +4425,20 @@ fn create_webview<T: UserEvent>(
   pending: PendingWebview<T, Wry<T>>,
   #[allow(unused_variables)] focused_webview: Arc<Mutex<Option<String>>>,
 ) -> Result<WebviewWrapper> {
+  if !context.webview_runtime_installed {
+    #[cfg(all(not(debug_assertions), windows))]
+    dialog::error(
+      r#"Could not find the WebView2 Runtime.
+
+Make sure it is installed or download it from <A href="https://developer.microsoft.com/en-us/microsoft-edge/webview2">https://developer.microsoft.com/en-us/microsoft-edge/webview2</A>
+
+You may have it installed on another user account, but it is not available for this one.
+"#,
+    );
+
+    return Err(Error::WebviewRuntimeNotInstalled);
+  }
+
   #[allow(unused_mut)]
   let PendingWebview {
     webview_attributes,

crates/tauri-runtime/src/lib.rs

@@ -169,6 +169,8 @@ pub enum Error {
   #[cfg(any(target_os = "macos", target_os = "ios"))]
   #[error("failed to remove data store")]
   FailedToRemoveDataStore,
+  #[error("Could not find the webview runtime, make sure it is installed")]
+  WebviewRuntimeNotInstalled,
 }
 
 /// Result type.

crates/tauri/Cargo.toml

@@ -185,6 +185,7 @@ unstable = ["tauri-runtime-wry?/unstable"]
 common-controls-v6 = [
   "tray-icon?/common-controls-v6",
   "muda/common-controls-v6",
+  "tauri-runtime-wry?/common-controls-v6",
 ]
 tray-icon = ["dep:tray-icon"]
 tracing = ["dep:tracing", "tauri-macros/tracing", "tauri-runtime-wry?/tracing"]