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Fix blank screen when clicking sign-in buttons in the desktop app #2

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Merged
devxsubh merged 1 commit into from
Oct 25, 2026
Merged

Fix blank screen when clicking sign-in buttons in the desktop app #2

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7 changes: 7 additions & 0 deletions desktop/src/ipc.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ export function registerIpc(opts: {
session: () => SessionInfo;
signOut: () => Promise<void>;
accountUrl: () => string;
shellAction: (action: string) => void;
}): void {
const navigate = opts.navigate;
ipcMain.on("capscreen:bootstrap", (e) => {
Expand All @@ -42,6 +43,12 @@ export function registerIpc(opts: {
void opts.signOut();
});

// Only the shell's data: pages (gate, boot error) may trigger these.
ipcMain.on("capscreen:shell-action", (e, action: unknown) => {
if (typeof action !== "string" || !e.senderFrame?.url.startsWith("data:")) return;
opts.shellAction(action);
});

ipcMain.handle("capscreen:open-account", async () => {
const url = opts.accountUrl();
if (url) await shell.openExternal(url);
Expand Down
33 changes: 19 additions & 14 deletions desktop/src/main.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -101,20 +101,6 @@ function createWindow(): void {
return { action: "deny" };
});
mainWindow.webContents.on("will-navigate", (e, url) => {
// Buttons on the sign-in gate.
const gateAction = /^about:blank#(signin|signup|reopen|cancel)$/.exec(url)?.[1];
if (gateAction) {
e.preventDefault();
void handleGateAction(gateAction);
return;
}
// Buttons on the boot error page.
if (url === "about:blank#retry" || url === "about:blank#logs") {
e.preventDefault();
if (url.endsWith("#logs")) void shell.openPath(userData("logs"));
else void mainWindow?.loadURL(`data:text/html;charset=utf-8,${encodeURIComponent(splashHtml())}`).then(start);
return;
}
const allowed = url.startsWith(APP_ORIGIN) || (runtime && url.startsWith(runtime.frontendUrl)) || url.startsWith("data:");
if (!allowed) {
e.preventDefault();
Expand Down Expand Up @@ -267,6 +253,24 @@ function requireSignIn(): Promise<void> {
return new Promise<void>((resolve) => (gateResolve = resolve));
}

/** Buttons on the shell pages (splash.ts), sent over IPC. */
function handleShellAction(action: string): void {
switch (action) {
case "signin":
case "signup":
case "reopen":
case "cancel":
void handleGateAction(action);
break;
case "logs":
void shell.openPath(userData("logs"));
break;
case "retry":
void showPage(splashHtml()).then(start);
break;
}
}

async function handleGateAction(action: string): Promise<void> {
if (action === "reopen" && pendingSignIn) {
await shell.openExternal(pendingSignIn.handle.authorizeUrl);
Expand Down Expand Up @@ -364,6 +368,7 @@ void app.whenReady().then(() => {
},
signOut: signOutAndGate,
accountUrl: () => AUTH_URL,
shellAction: handleShellAction,
});
buildMenu();
buildTray();
Expand Down
2 changes: 2 additions & 0 deletions desktop/src/preload.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,8 @@ contextBridge.exposeInMainWorld("capscreenDesktop", {
printToPdf: (opts: unknown) => ipcRenderer.invoke("capscreen:print-pdf", opts),
signOut: () => ipcRenderer.invoke("capscreen:sign-out"),
openAccount: () => ipcRenderer.invoke("capscreen:open-account"),
// Buttons on the shell's own pages (sign-in gate, boot error); ignored from the app UI.
shellAction: (action: string) => ipcRenderer.send("capscreen:shell-action", action),
onNavigate: (cb: (route: string) => void) => {
const listener = (_e: unknown, route: string) => cb(route);
ipcRenderer.on("capscreen:navigate", listener);
Expand Down
28 changes: 21 additions & 7 deletions desktop/src/splash.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,20 @@ const BASE_CSS = `
a.btn.primary { background: var(--fg); color: var(--bg); border-color: var(--fg); }
`;

/**
* Buttons carry data-action; clicks go to main.ts over the preload bridge.
* (Navigating to about:blank#… doesn't work: Chromium commits it without
* emitting will-navigate, so the window just went blank.)
*/
const ACTIONS_SCRIPT = `<script>
document.addEventListener("click", (e) => {
const el = e.target instanceof Element ? e.target.closest("[data-action]") : null;
if (!el) return;
e.preventDefault();
window.capscreenDesktop?.shellAction(el.getAttribute("data-action"));
});
</script>`;

export function splashHtml(): string {
return `<!doctype html><html><head><meta charset="utf-8"><title>CapScreen</title><style>${BASE_CSS}</style></head>
<body><div class="card">${markSvg()}<h1>CapScreen</h1><div class="spinner"></div>
Expand All @@ -53,29 +67,29 @@ export function errorHtml(message: string, logsDir: string): string {
<p>One of the local services failed to launch.</p>
<pre>${escapeHtml(message)}</pre>
<p style="font-size:12px">Logs: ${escapeHtml(logsDir)}</p>
<div class="row"><a class="btn" href="about:blank#logs">Open logs</a><a class="btn primary" href="about:blank#retry">Retry</a></div>
</div></body></html>`;
<div class="row"><a class="btn" href="#" data-action="logs">Open logs</a><a class="btn primary" href="#" data-action="retry">Retry</a></div>
</div>${ACTIONS_SCRIPT}</body></html>`;
}

export type SignInView = { state: "idle" } | { state: "waiting" } | { state: "error"; message: string };

/**
* Gate shown until the user signs in. Buttons navigate to about:blank#… and
* main.ts intercepts them (the page itself has no privileges).
* Gate shown until the user signs in. Buttons send their data-action to
* main.ts (the page itself has no privileges).
*/
export function signInHtml(view: SignInView): string {
const body =
view.state === "waiting"
? `<div class="spinner"></div>
<p>Finish signing in in your browser.</p>
<p style="font-size:12px">Didn't see a browser window?</p>
<div class="row"><a class="btn" href="about:blank#reopen">Open sign-in page again</a><a class="btn" href="about:blank#cancel">Cancel</a></div>`
<div class="row"><a class="btn" href="#" data-action="reopen">Open sign-in page again</a><a class="btn" href="#" data-action="cancel">Cancel</a></div>`
: `<p>Sign in with your CapScreen account to continue.</p>
<p style="font-size:12px">Your account controls access only. Cap tables, documents and screenings stay on this computer.</p>
${view.state === "error" ? `<pre>${escapeHtml(view.message)}</pre>` : ""}
<div class="row"><a class="btn primary" href="about:blank#signin">Sign in with browser</a><a class="btn" href="about:blank#signup">Create account</a></div>`;
<div class="row"><a class="btn primary" href="#" data-action="signin">Sign in with browser</a><a class="btn" href="#" data-action="signup">Create account</a></div>`;
return `<!doctype html><html><head><meta charset="utf-8"><title>CapScreen</title><style>${BASE_CSS}</style></head>
<body><div class="card">${markSvg()}<h1>Welcome to CapScreen</h1>${body}</div></body></html>`;
<body><div class="card">${markSvg()}<h1>Welcome to CapScreen</h1>${body}</div>${ACTIONS_SCRIPT}</body></html>`;
}

/** Shown in the browser tab after it hands the sign-in back to the app. */
Expand Down
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