Display error message on failed WebView page load (wavetermdev#1072)

closes wavetermdev#1023

Author: esimkowitz

frontend/app/view/webview/webview.less

@@ -9,13 +9,32 @@
     overflow: hidden;
     padding: 0;
     margin: 0;
+    user-select: none;
 
     // try to force pixel alignment to prevent
     // subpixel rendering artifacts
     transform: translate3d(0, 0, 0);
     will-change: transform;
 }
 
+.webview-error {
+    display: flex;
+    position: absolute;
+    background-color: black;
+    top: 0;
+    left: 0;
+    height: 100%;
+    width: 100%;
+    z-index: 100;
+    div {
+        font-size: x-large;
+        color: red;
+        display: flex;
+        margin: auto;
+        padding: 30px;
+    }
+}
+
 .block-frame-div-url {
     background: rgba(255, 255, 255, 0.1);
 

frontend/app/view/webview/webview.tsx

@@ -13,7 +13,7 @@ import { fireAndForget } from "@/util/util";
 import clsx from "clsx";
 import { WebviewTag } from "electron";
 import { Atom, PrimitiveAtom, atom, useAtomValue } from "jotai";
-import React, { memo, useEffect, useState } from "react";
+import { Fragment, createRef, memo, useEffect, useRef, useState } from "react";
 import "./webview.less";
 
 let webviewPreloadUrl = null;
@@ -68,8 +68,8 @@ export class WebViewModel implements ViewModel {
         this.refreshIcon = atom("rotate-right");
         this.viewIcon = atom("globe");
         this.viewName = atom("Web");
-        this.urlInputRef = React.createRef<HTMLInputElement>();
-        this.webviewRef = React.createRef<WebviewTag>();
+        this.urlInputRef = createRef<HTMLInputElement>();
+        this.webviewRef = createRef<WebviewTag>();
 
         this.mediaPlaying = atom(false);
         this.mediaMuted = atom(false);
@@ -477,14 +477,16 @@ const WebView = memo(({ model, onFailLoad }: WebViewProps) => {
     const defaultSearch = useAtomValue(defaultSearchAtom);
     let metaUrl = blockData?.meta?.url || defaultUrl;
     metaUrl = model.ensureUrlScheme(metaUrl, defaultSearch);
-    const metaUrlRef = React.useRef(metaUrl);
+    const metaUrlRef = useRef(metaUrl);
 
     // The initial value of the block metadata URL when the component first renders. Used to set the starting src value for the webview.
     const [metaUrlInitial] = useState(metaUrl);
 
     const [webContentsId, setWebContentsId] = useState(null);
     const [domReady, setDomReady] = useState(false);
 
+    const [errorText, setErrorText] = useState("");
+
     function setBgColor() {
         const webview = model.webviewRef.current;
         if (!webview) {
@@ -532,6 +534,7 @@ const WebView = memo(({ model, onFailLoad }: WebViewProps) => {
             return;
         }
         const navigateListener = (e: any) => {
+            setErrorText("");
             model.handleNavigate(e.url);
         };
         const newWindowHandler = (e: any) => {
@@ -554,7 +557,9 @@ const WebView = memo(({ model, onFailLoad }: WebViewProps) => {
             if (e.errorCode === -3) {
                 console.warn("Suppressed ERR_ABORTED error", e);
             } else {
-                console.error(`Failed to load ${e.validatedURL}: ${e.errorDescription}`);
+                const errorMessage = `Failed to load ${e.validatedURL}: ${e.errorDescription}`;
+                console.error(errorMessage);
+                setErrorText(errorMessage);
                 if (onFailLoad) {
                     const curUrl = model.webviewRef?.current.getURL();
                     onFailLoad(curUrl);
@@ -608,17 +613,24 @@ const WebView = memo(({ model, onFailLoad }: WebViewProps) => {
     }, []);
 
     return (
-        <webview
-            id="webview"
-            className="webview"
-            ref={model.webviewRef}
-            src={metaUrlInitial}
-            data-blockid={model.blockId}
-            data-webcontentsid={webContentsId} // needed for emain
-            preload={getWebviewPreloadUrl()}
-            // @ts-ignore This is a discrepancy between the React typing and the Chromium impl for webviewTag. Chrome webviewTag expects a string, while React expects a boolean.
-            allowpopups="true"
-        ></webview>
+        <Fragment>
+            <webview
+                id="webview"
+                className="webview"
+                ref={model.webviewRef}
+                src={metaUrlInitial}
+                data-blockid={model.blockId}
+                data-webcontentsid={webContentsId} // needed for emain
+                preload={getWebviewPreloadUrl()}
+                // @ts-ignore This is a discrepancy between the React typing and the Chromium impl for webviewTag. Chrome webviewTag expects a string, while React expects a boolean.
+                allowpopups="true"
+            />
+            {errorText && (
+                <div className="webview-error">
+                    <div>{errorText}</div>
+                </div>
+            )}
+        </Fragment>
     );
 });