fix: use format_callback::format_raw for channels (#13288)

* fix it

* Create change-pr-13288.md

* fixes

* fixes

* fix .change

Author: oscartbeaumont

.changes/change-pr-13288.md

@@ -0,0 +1,5 @@
+---
+"tauri": 'patch:bug'
+---
+
+Prevent the JavaScript runtime crashing when channel events fire in a webview that no longer has callbacks for the channel.

crates/tauri/src/ipc/channel.rs

@@ -20,7 +20,9 @@ use crate::{
   Manager, Runtime, State, Webview,
 };
 
-use super::{CallbackFn, InvokeError, InvokeResponseBody, IpcResponse, Request, Response};
+use super::{
+  format_callback, CallbackFn, InvokeError, InvokeResponseBody, IpcResponse, Request, Response,
+};
 
 pub const IPC_PAYLOAD_PREFIX: &str = "__CHANNEL__:";
 // TODO: Change this to `channel` in v3
@@ -149,15 +151,14 @@ impl JavaScriptChannelId {
         match body {
           // Don't go through the fetch process if the payload is small
           InvokeResponseBody::Json(string) if string.len() < MAX_JSON_DIRECT_EXECUTE_THRESHOLD => {
-            webview.eval(format!(
-              "window['_{callback_id}']({{ message: {string}, index: {current_index} }})"
+            webview.eval(format_callback::format_raw_js(
+              callback_id,
+              &format!("{{ message: {string}, index: {current_index} }}"),
             ))?;
           }
           InvokeResponseBody::Raw(bytes) if bytes.len() < MAX_RAW_DIRECT_EXECUTE_THRESHOLD => {
             let bytes_as_json_array = serde_json::to_string(&bytes)?;
-            webview.eval(format!(
-              "window['_{callback_id}']({{ message: new Uint8Array({bytes_as_json_array}).buffer, index: {current_index} }})",
-            ))?;
+            webview.eval(format_callback::format_raw_js(callback_id, &format!("{{ message: new Uint8Array({bytes_as_json_array}).buffer, index: {current_index} }}")))?;
           }
           // use the fetch API to speed up larger response payloads
           _ => {
@@ -180,8 +181,9 @@ impl JavaScriptChannelId {
       }),
       Some(Box::new(move || {
         let current_index = counter_clone.load(Ordering::Relaxed);
-        let _ = webview_clone.eval(format!(
-          "window['_{callback_id}']({{ end: true, index: {current_index} }})",
+        let _ = webview_clone.eval(format_callback::format_raw_js(
+          callback_id,
+          &format!("{{ end: true, index: {current_index} }}"),
         ));
       })),
     )
@@ -243,12 +245,13 @@ impl<TSend> Channel<TSend> {
         match body {
           // Don't go through the fetch process if the payload is small
           InvokeResponseBody::Json(string) if string.len() < MAX_JSON_DIRECT_EXECUTE_THRESHOLD => {
-            webview.eval(format!("window['_{callback_id}']({string})"))?;
+            webview.eval(format_callback::format_raw_js(callback_id, &string))?;
           }
           InvokeResponseBody::Raw(bytes) if bytes.len() < MAX_RAW_DIRECT_EXECUTE_THRESHOLD => {
             let bytes_as_json_array = serde_json::to_string(&bytes)?;
-            webview.eval(format!(
-              "window['_{callback_id}'](new Uint8Array({bytes_as_json_array}).buffer)",
+            webview.eval(format_callback::format_raw_js(
+              callback_id,
+              &format!("new Uint8Array({bytes_as_json_array}).buffer"),
             ))?;
           }
           // use the fetch API to speed up larger response payloads

crates/tauri/src/ipc/format_callback.rs

@@ -92,18 +92,22 @@ pub fn format<T: Serialize>(function_name: CallbackFn, arg: &T) -> crate::Result
 /// See [json-parse-benchmark](https://github.com/GoogleChromeLabs/json-parse-benchmark).
 pub fn format_raw(function_name: CallbackFn, json_string: String) -> crate::Result<String> {
   serialize_js_with(json_string, Default::default(), |arg| {
-    format!(
-      r#"
-    if (window["_{fn}"]) {{
-      window["_{fn}"]({arg})
-    }} else {{
-      console.warn("[TAURI] Couldn't find callback id {fn} in window. This happens when the app is reloaded while Rust is running an asynchronous operation.")
-    }}"#,
-      fn = function_name.0
-    )
+    format_raw_js(function_name.0, arg)
   })
 }
 
+/// Formats a callback function invocation, properly accounting for error handling.
+pub fn format_raw_js(id: u32, js: &str) -> String {
+  format!(
+    r#"
+  if (window["_{id}"]) {{
+    window["_{id}"]({js})
+  }} else {{
+    console.warn("[TAURI] Couldn't find callback id {id} in window. This happens when the app is reloaded while Rust is running an asynchronous operation.")
+  }}"#
+  )
+}
+
 /// Formats a serializable Result type to its Promise response.
 ///
 /// See [`format_result_raw`] for more information.