🔄 feat: Add Configurable Cache Headers for Index.html (#4565)

* refactor: move o1 model check, after vision request check

* feat(server): add configurable cache headers for index.html

• Add environment variables to control index.html cache headers
• Default to no-cache configuration for consistent app updates
• Document cache control options in .env.example

.env.example

@@ -491,3 +491,19 @@ HELP_AND_FAQ_URL=https://librechat.ai
 
 # E2E_USER_EMAIL=
 # E2E_USER_PASSWORD=
+
+#=====================================================#
+#                  Cache Headers                      #
+#=====================================================#
+#   Headers that control caching of the index.html    #
+#   Default configuration prevents caching to ensure  #
+#   users always get the latest version. Customize    #
+#   only if you understand caching implications.      #
+
+# INDEX_HTML_CACHE_CONTROL=no-cache, no-store, must-revalidate
+# INDEX_HTML_PRAGMA=no-cache
+# INDEX_HTML_EXPIRES=0
+
+# no-cache: Forces validation with server before using cached version
+# no-store: Prevents storing the response entirely
+# must-revalidate: Prevents using stale content when offline

api/app/clients/OpenAIClient.js

@@ -100,8 +100,6 @@ class OpenAIClient extends BaseClient {
       this.options.modelOptions,
     );
 
-    this.isO1Model = /\bo1\b/i.test(this.modelOptions.model);
-
     this.defaultVisionModel = this.options.visionModel ?? 'gpt-4-vision-preview';
     if (typeof this.options.attachments?.then === 'function') {
       this.options.attachments.then((attachments) => this.checkVisionRequest(attachments));
@@ -109,6 +107,8 @@ class OpenAIClient extends BaseClient {
       this.checkVisionRequest(this.options.attachments);
     }
 
+    this.isO1Model = /\bo1\b/i.test(this.modelOptions.model);
+
     const { OPENROUTER_API_KEY, OPENAI_FORCE_PROMPT } = process.env ?? {};
     if (OPENROUTER_API_KEY && !this.azure) {
       this.apiKey = OPENROUTER_API_KEY;

api/server/index.js

@@ -112,10 +112,16 @@ const startServer = async () => {
   app.use('/api/tags', routes.tags);
 
   app.use((req, res) => {
-    // Replace lang attribute in index.html with lang from cookies or accept-language header
+    res.set({
+      'Cache-Control': process.env.INDEX_CACHE_CONTROL || 'no-cache, no-store, must-revalidate',
+      Pragma: process.env.INDEX_PRAGMA || 'no-cache',
+      Expires: process.env.INDEX_EXPIRES || '0',
+    });
+
     const lang = req.cookies.lang || req.headers['accept-language']?.split(',')[0] || 'en-US';
-    const saneLang = lang.replace(/"/g, '"'); // sanitize untrusted user input
+    const saneLang = lang.replace(/"/g, '"');
     const updatedIndexHtml = indexHTML.replace(/lang="en-US"/g, `lang="${saneLang}"`);
+    res.type('html');
     res.send(updatedIndexHtml);
   });
 

index.html

@@ -7,10 +7,6 @@
     <meta name="mobile-web-app-capable" content="yes">
     <meta name="apple-mobile-web-app-capable" content="yes">
     <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
-    <!-- Cache Busting -->
-    <meta http-equiv='cache-control' content="no-cache, no-store, must-revalidate">
-    <meta http-equiv='expires' content='0'>
-    <meta http-equiv='pragma' content='no-cache'>
     <title>LibreChat</title>
     <link
       rel="shortcut icon"