🎯 refactor: Custom Endpoint Request-based Header Resolution (#9344)

* refactor: resolve request-based headers for custom endpoints right before LLM request

* ci: clarify request-based header resolution in initializeClient test

api/server/controllers/agents/client.js

@@ -7,6 +7,7 @@ const {
   createRun,
   Tokenizer,
   checkAccess,
+  resolveHeaders,
   getBalanceConfig,
   memoryInstructions,
   formatContentStrings,
@@ -879,6 +880,16 @@ class AgentClient extends BaseClient {
           memoryPromise = this.runMemory(messages);
         }
 
+        /** Resolve request-based headers for Custom Endpoints. Note: if this is added to
+         *  non-custom endpoints, needs consideration of varying provider header configs.
+         */
+        if (agent.model_parameters?.configuration?.defaultHeaders != null) {
+          agent.model_parameters.configuration.defaultHeaders = resolveHeaders({
+            headers: agent.model_parameters.configuration.defaultHeaders,
+            body: config.configurable.requestBody,
+          });
+        }
+
         run = await createRun({
           agent,
           req: this.options.req,
@@ -1181,6 +1192,20 @@ class AgentClient extends BaseClient {
       clientOptions.json = true;
     }
 
+    /** Resolve request-based headers for Custom Endpoints. Note: if this is added to
+     *  non-custom endpoints, needs consideration of varying provider header configs.
+     */
+    if (clientOptions?.configuration?.defaultHeaders != null) {
+      clientOptions.configuration.defaultHeaders = resolveHeaders({
+        headers: clientOptions.configuration.defaultHeaders,
+        body: {
+          messageId: this.responseMessageId,
+          conversationId: this.conversationId,
+          parentMessageId: this.parentMessageId,
+        },
+      });
+    }
+
     try {
       const titleResult = await this.run.generateTitle({
         provider,

api/server/services/Endpoints/custom/initialize.js

@@ -36,10 +36,12 @@ const initializeClient = async ({ req, res, endpointOption, optionsOnly, overrid
   const CUSTOM_API_KEY = extractEnvVariable(endpointConfig.apiKey);
   const CUSTOM_BASE_URL = extractEnvVariable(endpointConfig.baseURL);
 
+  /** Intentionally excludes passing `body`, i.e. `req.body`, as
+   *  values may not be accurate until `AgentClient` is initialized
+   */
   let resolvedHeaders = resolveHeaders({
     headers: endpointConfig.headers,
     user: req.user,
-    body: req.body,
   });
 
   if (CUSTOM_API_KEY.match(envVarRegex)) {

api/server/services/Endpoints/custom/initialize.spec.js

@@ -76,7 +76,10 @@ describe('custom/initializeClient', () => {
     expect(resolveHeaders).toHaveBeenCalledWith({
       headers: { 'x-user': '{{LIBRECHAT_USER_ID}}', 'x-email': '{{LIBRECHAT_USER_EMAIL}}' },
       user: { id: 'user-123', email: 'test@example.com', role: 'user' },
+      /**
+       * Note: Request-based Header Resolution is deferred until right before LLM request is made
       body: { endpoint: 'test-endpoint' }, // body - supports {{LIBRECHAT_BODY_*}} placeholders
+       */
     });
   });