display an error page on panic

Ekleog · Ekleog · commit 8fcf28a0ba14 · 2022-12-04T19:07:18.000+01:00
diff --git a/risuto-web/index.html b/risuto-web/index.html
@@ -1,13 +1,16 @@
 <!DOCTYPE html>
 <html lang="en">
-    <head>
-        <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
-        <link data-trunk rel="scss" href="scss/style.scss" />
-        <link data-trunk rel="copy-dir" href="vendor/bootstrap-icons-1.10.2/fonts" />
-        <link data-trunk rel="copy-file" href="vendor/bootstrap-5.2.2.bundle.min.js" />
-    </head>
-    <body>
-        <!-- TODO: use data-trunk script instead of copy-file then script -->
-        <script src="/bootstrap-5.2.2.bundle.min.js"></script>
-    </body>
+
+<head>
+    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+    <link data-trunk rel="scss" href="scss/style.scss" />
+    <link data-trunk rel="copy-dir" href="vendor/bootstrap-icons-1.10.2/fonts" />
+    <link data-trunk rel="copy-file" href="vendor/bootstrap-5.2.2.bundle.min.js" />
+</head>
+
+<body id="body">
+    <!-- TODO: use data-trunk script instead of copy-file then script -->
+    <script src="/bootstrap-5.2.2.bundle.min.js"></script>
+</body>
+
 </html>
diff --git a/risuto-web/panic-page.html b/risuto-web/panic-page.html
@@ -0,0 +1,7 @@
+<h1>Something unexpected occurred</h1>
+<p>
+    Please report an issue to <a href="https://github.com/Ekleog/risuto/issues">the bug tracker</a> with
+    information about what you were doing and anything that could be unusual about your usage, as well as the
+    below message:
+</p>
+<pre id="panic-message"></pre>
diff --git a/risuto-web/src/main.rs b/risuto-web/src/main.rs
@@ -1,3 +1,4 @@
+#![feature(panic_info_message)]
 use futures::{channel::oneshot, executor::block_on, FutureExt};
 use gloo_storage::{LocalStorage, Storage};
 use risuto_api::*;
@@ -11,6 +12,35 @@ mod ui;
 
 fn main() {
     tracing_wasm::set_as_global_default();
+    yew::set_custom_panic_hook(Box::new(|info| {
+        let mut message = match info.location() {
+            None => format!("Panic occurred at unknown place:\n"),
+            Some(l) => format!(
+                "Panic occurred at file '{}' line '{}':\n",
+                l.file(),
+                l.line()
+            ),
+        };
+        // TODO: when replacing this with console_error_panic_hook::stringify,
+        // we can stop depending on nightly
+        if let Some(m) = info.message() {
+            let _ = std::fmt::write(&mut message, *m);
+        } else {
+            message += "failed recovering a message from the panic";
+        }
+        let document = web_sys::window()
+            .expect("no web_sys window")
+            .document()
+            .expect("no web_sys document");
+        document
+            .get_element_by_id("body")
+            .expect("no #body element")
+            .set_inner_html(include_str!("../panic-page.html"));
+        document
+            .get_element_by_id("panic-message")
+            .expect("no #panic-message element")
+            .set_inner_html(&message);
+    }));
     yew::start_app::<App>();
 }
 
