fix: address review feedback and code scanning alerts

src/server/transformers/gemini/generate-content/index.test.ts

@@ -27,6 +27,24 @@ describe('geminiGenerateContentTransformer.inbound', () => {
     expect(geminiGenerateContentOutbound.resolveActionUrl).toBe(resolveGeminiGenerateContentUrl);
   });
 
+  it('preserves base-url query params when resolving Gemini endpoints', () => {
+    expect(
+      resolveGeminiNativeBaseUrl('https://example.com/native?alt=sse', 'v1beta'),
+    ).toBe('https://example.com/native/v1beta?alt=sse');
+    expect(
+      resolveGeminiModelsUrl('https://example.com/native?alt=sse', 'v1beta', 'api-key'),
+    ).toBe('https://example.com/native/v1beta/models?alt=sse&key=api-key');
+    expect(
+      resolveGeminiGenerateContentUrl(
+        'https://example.com/native?alt=sse',
+        'v1beta',
+        '/models/gemini-2.5-pro:generateContent',
+        'api-key',
+        '?trace=1',
+      ),
+    ).toBe('https://example.com/native/v1beta/models/gemini-2.5-pro:generateContent?alt=sse&trace=1&key=api-key');
+  });
+
   it('parses native Gemini requests into canonical envelopes', () => {
     const result = geminiGenerateContentTransformer.parseRequest({
       model: 'gemini-2.5-pro',

src/server/transformers/gemini/generate-content/urlResolver.ts

@@ -1,15 +1,33 @@
-function normalizeBaseUrl(baseUrl: string): string {
-  return (baseUrl || '').replace(/\/+$/, '');
+function normalizePathname(pathname: string): string {
+  let normalized = pathname || '';
+  while (normalized.endsWith('/')) {
+    normalized = normalized.slice(0, -1);
+  }
+  return normalized;
 }
 
-function baseIncludesVersion(baseUrl: string): boolean {
-  return /\/v\d+(?:beta)?(?:\/|$)/i.test(baseUrl);
+function splitBaseUrl(baseUrl: string): { path: string; query: string } {
+  const raw = baseUrl || '';
+  const queryIndex = raw.indexOf('?');
+  if (queryIndex < 0) {
+    return { path: normalizePathname(raw), query: '' };
+  }
+  return {
+    path: normalizePathname(raw.slice(0, queryIndex)),
+    query: raw.slice(queryIndex + 1),
+  };
+}
+
+function baseIncludesVersion(path: string): boolean {
+  return /\/v\d+(?:beta)?(?:\/|$)/i.test(path);
 }
 
 export function resolveGeminiNativeBaseUrl(baseUrl: string, apiVersion: string): string {
-  const normalized = normalizeBaseUrl(baseUrl);
-  if (baseIncludesVersion(normalized)) return normalized;
-  return `${normalized}/${apiVersion}`;
+  const { path, query } = splitBaseUrl(baseUrl);
+  const normalizedPath = baseIncludesVersion(path)
+    ? path
+    : `${path}/${apiVersion.replace(/^\/+/, '')}`;
+  return `${normalizedPath}${query ? `?${query}` : ''}`;
 }
 
 export function resolveGeminiModelsUrl(
@@ -18,8 +36,10 @@ export function resolveGeminiModelsUrl(
   apiKey: string,
 ): string {
   const base = resolveGeminiNativeBaseUrl(baseUrl, apiVersion);
-  const separator = base.includes('?') ? '&' : '?';
-  return `${base}/models${separator}key=${encodeURIComponent(apiKey)}`;
+  const [path, query = ''] = base.split('?', 2);
+  const params = new URLSearchParams(query);
+  params.set('key', apiKey);
+  return `${path}/models?${params.toString()}`;
 }
 
 export function resolveGeminiGenerateContentUrl(
@@ -31,8 +51,13 @@ export function resolveGeminiGenerateContentUrl(
 ): string {
   const base = resolveGeminiNativeBaseUrl(baseUrl, apiVersion);
   const normalizedAction = modelActionPath.replace(/^\/+/, '');
-  const params = new URLSearchParams(search.startsWith('?') ? search.slice(1) : search);
+  const [path, baseQuery = ''] = base.split('?', 2);
+  const params = new URLSearchParams(baseQuery);
+  const extraParams = new URLSearchParams(search.startsWith('?') ? search.slice(1) : search);
+  for (const [key, value] of extraParams) {
+    params.set(key, value);
+  }
   params.set('key', apiKey);
   const query = params.toString();
-  return `${base}/${normalizedAction}${query ? `?${query}` : ''}`;
+  return `${path}/${normalizedAction}${query ? `?${query}` : ''}`;
 }