Fix mockttp admin stream monitoring and actively restart on disconnection

This isn't great, but it's better than the current result where the app
effectively breaks silently, and then crashes and resets your rules
whenever any rule change is saved.

Author: pimterry

src/model/proxy-store.ts

@@ -37,6 +37,7 @@ import { lazyObservablePromise } from '../util/observable';
 import { persist, hydrate } from '../util/mobx-persist/persist';
 import { isValidPort } from './network';
 import { serverVersion } from '../services/service-versions';
+import { DesktopApi } from '../services/desktop-api';
 
 type HtkAdminClient =
     // WebRTC is only supported for new servers:
@@ -224,16 +225,29 @@ export class ProxyStore {
     });
 
     private monitorRemoteClientConnection(client: PluggableAdmin.AdminClient<{}>) {
-        client.on('admin-client:stream-error', (err) => {
+        client.on('stream-error', (err) => {
             console.log('Admin client stream error');
             logError(err.message ? err : new Error('Client stream error'), { cause: err });
         });
-        client.on('admin-client:subscription-error', (err) => {
+        client.on('subscription-error', (err) => {
             console.log('Admin client subscription error');
             logError(err.message ? err : new Error('Client subscription error'), { cause: err });
         });
-        client.on('admin-client:stream-reconnect-failed', (err) => {
+        client.on('stream-reconnect-failed', (err) => {
             logError(err.message ? err : new Error('Client reconnect error'), { cause: err });
+
+            alert("Server disconnected unexpectedly, app restart required.\n\nPlease report this at github.com/httptoolkit/httptoolkit.");
+            setTimeout(() => { // Tiny wait for any other UI events to fire (error reporting/logging/other UI responsiveness)
+                if (DesktopApi.restartApp) {
+                    // Where possible (recent desktop release) we restart the whole app directly
+                    DesktopApi.restartApp();
+                } else if (!navigator.platform?.startsWith('Mac')) {
+                    // If not, on Windows & Linux we just close the window (which restarts)
+                    window.close();
+                }
+                // On Mac, app exit is independent from window exit, so we can't force that here,
+                // but hopefully this alert will lead the user to do so themselves.
+            }, 10);
         });
     }
 

src/services/desktop-api.ts

@@ -30,6 +30,7 @@ declare global {
 interface DesktopApi {
     selectApplication?: () => Promise<string | undefined>;
     openContextMenu?: (options: NativeContextMenuDefinition) => Promise<string | undefined>;
+    restartApp?: () => Promise<void>;
 }
 
 interface NativeContextMenuDefinition {