electron 15 fix navigation and support base64 data with whitespace

src/main/main.ts

@@ -190,10 +190,13 @@ app.on('ready', () => {
 });
 
 app.on("web-contents-created", (_event: any, webContents: WebContents) => {
-    // Prevent navigation
+    // Prevent navigation to local links
     webContents.on('will-navigate', (event: Event, navigationUrl) => {
-        console.warn(`Navigation is not allowed; attempted navigation to: ${navigationUrl}`);
-        event.preventDefault();
+        const jlabBaseUrl = `http://localhost:${appConfig.jlabPort}/`;
+        if (navigationUrl.startsWith(jlabBaseUrl) && navigationUrl.indexOf('#') !== -1) {
+            console.warn(`Navigation is not allowed; attempted navigation to: ${navigationUrl}`);
+            event.preventDefault();
+        }
     });
 
     // handle page's beforeunload prompt natively

src/main/preload.ts

@@ -0,0 +1,39 @@
+// atob implementation below is modified from node.js source 
+// (https://github.com/nodejs/node/blob/master/lib/buffer.js)
+// and copyright below is for it
+
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+window.atob = (input): string => {
+    const kBase64Digits =
+        'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
+
+    // remove whitespace
+    input = `${input}`.replace(/\s/g, "");
+    for (let n = 0; n < input.length; n++) {
+        if (!kBase64Digits.includes(input[n])) {
+            throw new DOMException('Invalid character', 'InvalidCharacterError');
+        }
+    }
+
+    return Buffer.from(input, 'base64').toString('latin1');
+}

src/main/sessions.ts

@@ -403,7 +403,8 @@ class JupyterLabSession {
             title: 'JupyterLab',
             webPreferences: {
                 nodeIntegration: true,
-                contextIsolation: false
+                contextIsolation: false,
+                preload: path.join(__dirname, './preload.js'),
             }
         });