feat: Implement basic general folder support (#2051)

- Related: #1748

src/ha/sign-path.ts

@@ -0,0 +1,33 @@
+import { SignedPath, signedPathSchema } from '../types';
+import { HomeAssistant } from './types';
+import { homeAssistantWSRequest } from './ws-request';
+
+/**
+ * Request that HA sign a path. May throw.
+ * @param hass The HomeAssistant object used to request the signature.
+ * @param path The path to sign.
+ * @param expires An optional number of seconds to sign the path for (by default
+ * HA will sign for 30 seconds).
+ * @returns The signed URL, or null if the response was malformed.
+ */
+
+export async function homeAssistantSignPath(
+  hass: HomeAssistant,
+  path: string,
+  expires?: number,
+): Promise<string | null> {
+  const request = {
+    type: 'auth/sign_path',
+    path: path,
+    expires: expires,
+  };
+  const response = await homeAssistantWSRequest<SignedPath>(
+    hass,
+    signedPathSchema,
+    request,
+  );
+  if (!response) {
+    return null;
+  }
+  return hass.hassUrl(response.path);
+}