🏷️ feat: Request Body Placeholders in Custom Headers

api/app/clients/OpenAIClient.js

@@ -653,8 +653,10 @@ class OpenAIClient extends BaseClient {
     if (headers && typeof headers === 'object' && !Array.isArray(headers)) {
       configOptions.baseOptions = {
         headers: resolveHeaders({
-          ...headers,
-          ...configOptions?.baseOptions?.headers,
+          headers: {
+            ...headers,
+            ...configOptions?.baseOptions?.headers,
+          },
         }),
       };
     }
@@ -749,7 +751,7 @@ class OpenAIClient extends BaseClient {
         groupMap,
       });
 
-      this.options.headers = resolveHeaders(headers);
+      this.options.headers = resolveHeaders({ headers });
       this.options.reverseProxyUrl = baseURL ?? null;
       this.langchainProxy = extractBaseURL(this.options.reverseProxyUrl);
       this.apiKey = azureOptions.azureOpenAIApiKey;
@@ -1181,7 +1183,7 @@ ${convo}
           modelGroupMap,
           groupMap,
         });
-        opts.defaultHeaders = resolveHeaders(headers);
+        opts.defaultHeaders = resolveHeaders({ headers });
         this.langchainProxy = extractBaseURL(baseURL);
         this.apiKey = azureOptions.azureOpenAIApiKey;
 

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

@@ -109,14 +109,14 @@ const initializeClient = async ({ req, res, version, endpointOption, initAppClie
 
     apiKey = azureOptions.azureOpenAIApiKey;
     opts.defaultQuery = { 'api-version': azureOptions.azureOpenAIApiVersion };
-    opts.defaultHeaders = resolveHeaders(
-      {
+    opts.defaultHeaders = resolveHeaders({
+      headers: {
         ...headers,
         'api-key': apiKey,
         'OpenAI-Beta': `assistants=${version}`,
       },
-      req.user,
-    );
+      user: req.user,
+    });
     opts.model = azureOptions.azureOpenAIApiDeploymentName;
 
     if (initAppClient) {

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

@@ -28,7 +28,11 @@ const initializeClient = async ({ req, res, endpointOption, optionsOnly, overrid
   const CUSTOM_API_KEY = extractEnvVariable(endpointConfig.apiKey);
   const CUSTOM_BASE_URL = extractEnvVariable(endpointConfig.baseURL);
 
-  let resolvedHeaders = resolveHeaders(endpointConfig.headers, req.user);
+  let resolvedHeaders = resolveHeaders({
+    headers: endpointConfig.headers,
+    user: req.user,
+    body: req.body,
+  });
 
   if (CUSTOM_API_KEY.match(envVarRegex)) {
     throw new Error(`Missing API Key for ${endpoint}.`);

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

@@ -64,13 +64,14 @@ describe('custom/initializeClient', () => {
     jest.clearAllMocks();
   });
 
-  it('calls resolveHeaders with headers and user', async () => {
+  it('calls resolveHeaders with headers, user, and body for body placeholder support', async () => {
     const { resolveHeaders } = require('@librechat/api');
     await initializeClient({ req: mockRequest, res: mockResponse, optionsOnly: true });
-    expect(resolveHeaders).toHaveBeenCalledWith(
-      { 'x-user': '{{LIBRECHAT_USER_ID}}', 'x-email': '{{LIBRECHAT_USER_EMAIL}}' },
-      { id: 'user-123', email: '[email protected]' },
-    );
+    expect(resolveHeaders).toHaveBeenCalledWith({
+      headers: { 'x-user': '{{LIBRECHAT_USER_ID}}', 'x-email': '{{LIBRECHAT_USER_EMAIL}}' },
+      user: { id: 'user-123', email: '[email protected]' },
+      body: { endpoint: 'test-endpoint' }, // body - supports {{LIBRECHAT_BODY_*}} placeholders
+    });
   });
 
   it('throws if endpoint config is missing', async () => {

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

@@ -81,10 +81,10 @@ const initializeClient = async ({
     serverless = _serverless;
 
     clientOptions.reverseProxyUrl = baseURL ?? clientOptions.reverseProxyUrl;
-    clientOptions.headers = resolveHeaders(
-      { ...headers, ...(clientOptions.headers ?? {}) },
-      req.user,
-    );
+    clientOptions.headers = resolveHeaders({
+      headers: { ...headers, ...(clientOptions.headers ?? {}) },
+      user: req.user,
+    });
 
     clientOptions.titleConvo = azureConfig.titleConvo;
     clientOptions.titleModel = azureConfig.titleModel;

librechat.example.yaml

@@ -290,6 +290,8 @@ endpoints:
       # recommended environment variables:
       apiKey: '${OPENROUTER_KEY}'
       baseURL: 'https://openrouter.ai/api/v1'
+      headers:
+          x-librechat-body-parentmessageid: '{{LIBRECHAT_BODY_PARENTMESSAGEID}}'
       models:
         default: ['meta-llama/llama-3-70b-instruct']
         fetch: true

packages/api/src/endpoints/openai/initialize.ts

@@ -87,10 +87,10 @@ export const initializeOpenAI = async ({
     });
 
     clientOptions.reverseProxyUrl = configBaseURL ?? clientOptions.reverseProxyUrl;
-    clientOptions.headers = resolveHeaders(
-      { ...headers, ...(clientOptions.headers ?? {}) },
-      req.user,
-    );
+    clientOptions.headers = resolveHeaders({
+      headers: { ...headers, ...(clientOptions.headers ?? {}) },
+      user: req.user,
+    });
 
     const groupName = modelGroupMap[modelName || '']?.group;
     if (groupName && groupMap[groupName]) {

packages/api/src/mcp/MCPConnectionFactory.ts

@@ -57,7 +57,11 @@ export class MCPConnectionFactory {
   }
 
   protected constructor(basic: BasicConnectionOptions, oauth?: OAuthConnectionOptions) {
-    this.serverConfig = processMCPEnv(basic.serverConfig, oauth?.user, oauth?.customUserVars);
+    this.serverConfig = processMCPEnv({
+      obj: basic.serverConfig,
+      user: oauth?.user,
+      customUserVars: oauth?.customUserVars,
+    });
     this.serverName = basic.serverName;
     this.useOAuth = !!oauth?.useOAuth;
     this.logPrefix = oauth?.user

packages/api/src/mcp/MCPServersRegistry.ts

@@ -38,7 +38,7 @@ export class MCPServersRegistry {
 
   constructor(configs: t.MCPServers) {
     this.rawConfigs = configs;
-    this.parsedConfigs = mapValues(configs, (con) => processMCPEnv(con));
+    this.parsedConfigs = mapValues(configs, (con) => processMCPEnv({ obj: con }));
     this.connections = new ConnectionsRepository(configs);
   }
 

packages/api/src/mcp/__tests__/MCPConnectionFactory.test.ts

@@ -74,7 +74,7 @@ describe('MCPConnectionFactory', () => {
       const connection = await MCPConnectionFactory.create(basicOptions);
 
       expect(connection).toBe(mockConnectionInstance);
-      expect(mockProcessMCPEnv).toHaveBeenCalledWith(mockServerConfig, undefined, undefined);
+      expect(mockProcessMCPEnv).toHaveBeenCalledWith({ obj: mockServerConfig });
       expect(mockMCPConnection).toHaveBeenCalledWith({
         serverName: 'test-server',
         serverConfig: mockServerConfig,
@@ -115,7 +115,7 @@ describe('MCPConnectionFactory', () => {
       const connection = await MCPConnectionFactory.create(basicOptions, oauthOptions);
 
       expect(connection).toBe(mockConnectionInstance);
-      expect(mockProcessMCPEnv).toHaveBeenCalledWith(mockServerConfig, mockUser, undefined);
+      expect(mockProcessMCPEnv).toHaveBeenCalledWith({ obj: mockServerConfig, user: mockUser });
       expect(mockMCPConnection).toHaveBeenCalledWith({
         serverName: 'test-server',
         serverConfig: mockServerConfig,

packages/api/src/mcp/__tests__/MCPServersRegistry.test.ts

@@ -24,7 +24,7 @@ jest.mock('@librechat/data-schemas', () => ({
 // Mock processMCPEnv to verify it's called and adds a processed marker
 jest.mock('~/utils', () => ({
   ...jest.requireActual('~/utils'),
-  processMCPEnv: jest.fn((config) => ({
+  processMCPEnv: jest.fn(({ obj: config }) => ({
     ...config,
     _processed: true, // Simple marker to verify processing occurred
   })),