Add Databricks auth support and custom header option to gemini cli (#11893)

Co-authored-by: Taylor Mullen <ntaylormullen@google.com>

packages/core/src/utils/customHeaderUtils.ts

@@ -0,0 +1,41 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * Parses custom headers and returns a map of key and vallues
+ */
+export function parseCustomHeaders(
+  envValue: string | undefined,
+): Record<string, string> {
+  const headers: Record<string, string> = {};
+  if (!envValue) {
+    return headers;
+  }
+
+  // Split the string on commas that are followed by a header key (key:),
+  // but ignore commas that are part of a header value (including values with colons or commas)
+  for (const entry of envValue.split(/,(?=\s*[^,:]+:)/)) {
+    const trimmedEntry = entry.trim();
+    if (!trimmedEntry) {
+      continue;
+    }
+
+    const separatorIndex = trimmedEntry.indexOf(':');
+    if (separatorIndex === -1) {
+      continue;
+    }
+
+    const name = trimmedEntry.slice(0, separatorIndex).trim();
+    const value = trimmedEntry.slice(separatorIndex + 1).trim();
+    if (!name) {
+      continue;
+    }
+
+    headers[name] = value;
+  }
+
+  return headers;
+}