implement demo mode

plugin/src/demo-guards.js

@@ -0,0 +1,54 @@
+// Demo-mode UX guards that run at the document level.
+//
+// Disable any email/password inputs to prevent users from entering credentials into a server they don't control.
+
+const PLACEHOLDER =
+  "Disabled in demo. Don't enter credentials on a server you don't control.";
+
+function isDemoMode() {
+  return document.body && document.body.dataset.demoMode === "true";
+}
+
+function disableInputs(root) {
+  const inputs = root.querySelectorAll(
+    'input[type="email"], input[type="password"]',
+  );
+
+  for (const input of inputs) {
+    if (input.dataset.ignisDemoDisabled === "1") {
+      continue;
+    }
+
+    input.disabled = true;
+    input.value = "";
+    input.placeholder = PLACEHOLDER;
+    input.dataset.ignisDemoDisabled = "1";
+  }
+}
+
+let observer = null;
+
+function startDemoGuards() {
+  if (!isDemoMode() || observer) {
+    return;
+  }
+
+  // Walk what's already there.
+  disableInputs(document.body);
+
+  // And watch for anything added later (login modals, plugin dialogs, etc.).
+  observer = new MutationObserver(() => {
+    disableInputs(document.body);
+  });
+
+  observer.observe(document.body, { childList: true, subtree: true });
+}
+
+function stopDemoGuards() {
+  if (observer) {
+    observer.disconnect();
+    observer = null;
+  }
+}
+
+module.exports = { startDemoGuards, stopDemoGuards };

plugin/src/main.js

@@ -4,6 +4,7 @@ const { patchSettingsModal, unpatchSettingsModal } = require("./settings/inject"
 const pluginRegistry = require("./plugin-registry");
 const { initStatusBar } = require("./status-bar");
 const { WorkspacePickerModal } = require("./workspace-picker");
+const { startDemoGuards, stopDemoGuards } = require("./demo-guards");
 
 window.__obsidianAPI = require("obsidian");
 
@@ -13,6 +14,7 @@ class IgnisBridgePlugin extends Plugin {
 
     await pluginRegistry.refresh();
     patchSettingsModal(this);
+    startDemoGuards();
     this._statusBarInterval = initStatusBar(this);
 
     this.addRibbonIcon("upload", "Upload file", () => {
@@ -44,6 +46,7 @@ class IgnisBridgePlugin extends Plugin {
     }
 
     unpatchSettingsModal(this);
+    stopDemoGuards();
     console.log("[ignis-bridge] Plugin unloaded");
   }
 }