feat/ allow webview2 (windows) to use optional user_data folder provi…

…ded by the attributes. (#120)

* WIP: Allow webview2 to use optional user_data folder.

Actually only supported on Windows.
Attention the folder need to exist or webview will failed to run.

* Use `./target/webview_data` as sample directory for `user_data_path` example.

* Use canonicalized path as we require an absolute path for the webview

* Make sure to create the directory before we can canonicalize

* fmt

examples/custom_user_data.rs

@@ -0,0 +1,27 @@
+use std::{fs, path::PathBuf};
+use wry::{Application, Attributes, Result};
+
+fn main() -> Result<()> {
+  let mut app = Application::new()?;
+
+  // Use a sample directory at the root of the project
+  let mut test_path = PathBuf::from("./target/webview_data");
+  // The directory need to exist or the Webview will panic
+  fs::create_dir_all(&test_path)?;
+  // We need an absoulte path for the webview
+  test_path = fs::canonicalize(&test_path)?;
+  // The directory need to exist or the Webview will panic
+  println!("Webview storage path: {:#?}", &test_path);
+
+  let attributes = Attributes {
+    url: Some("https://tauri.studio/".to_string()),
+    title: String::from("Hello World!"),
+    // Currently supported only on Windows
+    user_data_path: Some(test_path),
+    ..Default::default()
+  };
+
+  app.add_window(attributes)?;
+  app.run();
+  Ok(())
+}

src/application/attributes.rs

@@ -1,6 +1,9 @@
 use crate::{Result, RpcRequest, RpcResponse, WindowProxy};
 
-use std::{fs::read, path::Path};
+use std::{
+  fs::read,
+  path::{Path, PathBuf},
+};
 
 /// The RPC handler to Communicate between the host Rust code and Javascript on webview.
 ///
@@ -191,6 +194,11 @@ pub struct Attributes {
   ///
   /// The default is an empty vector.
   pub initialization_scripts: Vec<String>,
+
+  /// Webview user data path.
+  ///
+  /// The default is `None`.
+  pub user_data_path: Option<PathBuf>,
 }
 
 impl Attributes {
@@ -220,6 +228,7 @@ impl Attributes {
         transparent: self.transparent,
         url: self.url,
         initialization_scripts: self.initialization_scripts,
+        user_data_path: self.user_data_path,
       },
     )
   }
@@ -249,6 +258,7 @@ impl Default for Attributes {
       skip_taskbar: false,
       url: None,
       initialization_scripts: vec![],
+      user_data_path: None,
     }
   }
 }
@@ -278,4 +288,5 @@ pub(crate) struct InnerWebViewAttributes {
   pub transparent: bool,
   pub url: Option<String>,
   pub initialization_scripts: Vec<String>,
+  pub user_data_path: Option<PathBuf>,
 }

src/application/general.rs

@@ -354,7 +354,10 @@ fn _create_webview(
 ) -> Result<WebView> {
   let window_id = window.id();
 
-  let mut webview = WebViewBuilder::new(window)?.transparent(attributes.transparent);
+  let mut webview = WebViewBuilder::new(window)?
+    .transparent(attributes.transparent)
+    .user_data_path(attributes.user_data_path);
+
   for js in attributes.initialization_scripts {
     webview = webview.initialize_script(&js);
   }

src/webview/linux/mod.rs

@@ -5,7 +5,7 @@ use crate::{
   Error, FileDropHandler, Result, RpcHandler,
 };
 
-use std::rc::Rc;
+use std::{path::PathBuf, rc::Rc};
 
 use gdk::RGBA;
 use gio::Cancellable;
@@ -33,6 +33,7 @@ impl WV for InnerWebView {
     custom_protocol: Option<(String, F)>,
     rpc_handler: Option<RpcHandler>,
     file_drop_handler: Option<FileDropHandler>,
+    _user_data_path: Option<PathBuf>,
   ) -> Result<Self> {
     // Webview widget
     let manager = UserContentManager::new();

src/webview/macos/mod.rs

@@ -9,6 +9,7 @@ use file_drop::{add_file_drop_methods, set_file_drop_handler};
 use std::{
   ffi::{c_void, CStr},
   os::raw::c_char,
+  path::PathBuf,
   ptr::null,
   slice, str,
 };
@@ -42,6 +43,7 @@ impl WV for InnerWebView {
     custom_protocol: Option<(String, F)>,
     rpc_handler: Option<RpcHandler>,
     file_drop_handler: Option<FileDropHandler>,
+    _user_data_path: Option<PathBuf>,
   ) -> Result<Self> {
     // Function for rpc handler
     extern "C" fn did_receive(this: &Object, _: Sel, _: id, msg: id) {

src/webview/mod.rs

@@ -17,7 +17,10 @@ use win::*;
 
 use crate::{Error, FileDropHandler, Result};
 
-use std::sync::mpsc::{channel, Receiver, Sender};
+use std::{
+  path::PathBuf,
+  sync::mpsc::{channel, Receiver, Sender},
+};
 
 use serde_json::Value;
 use url::Url;
@@ -85,6 +88,7 @@ pub struct WebViewBuilder {
   custom_protocol: Option<(String, Box<dyn Fn(&str) -> Result<Vec<u8>>>)>,
   rpc_handler: Option<RpcHandler>,
   file_drop_handler: Option<FileDropHandler>,
+  user_data_path: Option<PathBuf>,
 }
 
 impl WebViewBuilder {
@@ -102,6 +106,7 @@ impl WebViewBuilder {
       custom_protocol: None,
       rpc_handler: None,
       file_drop_handler: None,
+      user_data_path: None,
     })
   }
 
@@ -120,6 +125,13 @@ impl WebViewBuilder {
     self
   }
 
+  /// Whether the WebView window should have a custom user data path. This is usefull in Windows
+  /// when a bundled application can't have the webview data inside `Program Files`.
+  pub fn user_data_path(mut self, user_data_path: Option<PathBuf>) -> Self {
+    self.user_data_path = user_data_path;
+    self
+  }
+
   /// Create a [`Dispatcher`] to send evaluation scripts to the WebView. [`WebView`] is not thread
   /// safe because it must be run on the main thread who creates it. [`Dispatcher`] can let you
   /// send the scripts from other threads.
@@ -213,6 +225,7 @@ impl WebViewBuilder {
       self.custom_protocol,
       self.rpc_handler,
       self.file_drop_handler,
+      self.user_data_path,
     )?;
     Ok(WebView {
       window: self.window,
@@ -251,7 +264,16 @@ impl WebView {
   pub fn new_with_configs(window: Window, transparent: bool) -> Result<Self> {
     let picky_none: Option<(String, Box<dyn Fn(&str) -> Result<Vec<u8>>>)> = None;
 
-    let webview = InnerWebView::new(&window, vec![], None, transparent, picky_none, None, None)?;
+    let webview = InnerWebView::new(
+      &window,
+      vec![],
+      None,
+      transparent,
+      picky_none,
+      None,
+      None,
+      None,
+    )?;
 
     let (tx, rx) = channel();
 
@@ -327,6 +349,7 @@ pub(crate) trait WV: Sized {
     custom_protocol: Option<(String, F)>,
     rpc_handler: Option<RpcHandler>,
     file_drop_handler: Option<FileDropHandler>,
+    user_data_path: Option<PathBuf>,
   ) -> Result<Self>;
 
   fn eval(&self, js: &str) -> Result<()>;

src/webview/win/mod.rs

@@ -7,7 +7,7 @@ use crate::{
 
 use file_drop::FileDropController;
 
-use std::{os::raw::c_void, rc::Rc};
+use std::{os::raw::c_void, path::PathBuf, rc::Rc};
 
 use once_cell::unsync::OnceCell;
 use url::Url;
@@ -37,6 +37,7 @@ impl WV for InnerWebView {
     custom_protocol: Option<(String, F)>,
     rpc_handler: Option<RpcHandler>,
     file_drop_handler: Option<FileDropHandler>,
+    user_data_path: Option<PathBuf>,
   ) -> Result<Self> {
     let hwnd = window.hwnd() as HWND;
 
@@ -46,8 +47,19 @@ impl WV for InnerWebView {
     let file_drop_controller: Rc<OnceCell<FileDropController>> = Rc::new(OnceCell::new());
     let file_drop_controller_clone = file_drop_controller.clone();
 
+    let webview_builder: webview2::EnvironmentBuilder;
+    let user_data_path_provided: PathBuf;
+
+    if user_data_path.is_some() {
+      user_data_path_provided = user_data_path.unwrap();
+      webview_builder =
+        webview2::EnvironmentBuilder::new().with_user_data_folder(&user_data_path_provided);
+    } else {
+      webview_builder = webview2::EnvironmentBuilder::new();
+    }
+
     // Webview controller
-    webview2::EnvironmentBuilder::new().build(move |env| {
+    webview_builder.build(move |env| {
       let env = env?;
       let env_ = env.clone();
       env.create_controller(hwnd, move |controller| {