add: support custom headers

Dockerfile

@@ -4,7 +4,21 @@ WORKDIR /app
 
 COPY . .
 
-RUN npm ci --ignore-scripts && \
+
+RUN npm install
+
+
+RUN cd client && \
+    npm install && \
+    npm run build
+
+
+RUN cd server && \
+    npm install && \
+    npm run build
+
+RUN cd cli && \
+    npm install && \
     npm run build
 
 FROM node:20-alpine
@@ -22,5 +36,4 @@ RUN npm ci --omit=dev --ignore-scripts
 
 ENV NODE_ENV=production
 
-
 CMD ["node", "client/bin/start.js"] 

client/package.json

@@ -51,7 +51,7 @@
   "devDependencies": {
     "@eslint/js": "^9.11.1",
     "@testing-library/jest-dom": "^6.6.3",
-    "@testing-library/react": "^16.2.0",
+    "@testing-library/react": "^14.2.1",
     "@types/jest": "^29.5.14",
     "@types/node": "^22.7.5",
     "@types/prismjs": "^1.26.5",

client/src/App.tsx

@@ -109,6 +109,11 @@ const App = () => {
     return localStorage.getItem("lastHeaderName") || "";
   });
 
+  const [customHeaders, setCustomHeaders] = useState<[string, string][]>(() => {
+    const saved = localStorage.getItem("lastCustomHeaders");
+    return saved ? JSON.parse(saved) : [];
+  });
+
   const [pendingSampleRequests, setPendingSampleRequests] = useState<
     Array<
       PendingRequest & {
@@ -183,6 +188,7 @@ const App = () => {
     env,
     bearerToken,
     headerName,
+    customHeaders,
     config,
     onNotification: (notification) => {
       setNotifications((prev) => [...prev, notification as ServerNotification]);
@@ -226,6 +232,10 @@ const App = () => {
     localStorage.setItem("lastHeaderName", headerName);
   }, [headerName]);
 
+  useEffect(() => {
+    localStorage.setItem("lastCustomHeaders", JSON.stringify(customHeaders));
+  }, [customHeaders]);
+
   useEffect(() => {
     localStorage.setItem(CONFIG_LOCAL_STORAGE_KEY, JSON.stringify(config));
   }, [config]);
@@ -581,6 +591,8 @@ const App = () => {
         setBearerToken={setBearerToken}
         headerName={headerName}
         setHeaderName={setHeaderName}
+        customHeaders={customHeaders}
+        setCustomHeaders={setCustomHeaders}
         onConnect={connectMcpServer}
         onDisconnect={disconnectMcpServer}
         stdErrNotifications={stdErrNotifications}

client/src/components/Sidebar.tsx

@@ -40,7 +40,8 @@ import {
 } from "@/components/ui/tooltip";
 import { useToast } from "../lib/hooks/useToast";
 
-interface SidebarProps {
+export interface SidebarProps {
+
   connectionStatus: ConnectionStatus;
   transportType: "stdio" | "sse" | "streamable-http";
   setTransportType: (type: "stdio" | "sse" | "streamable-http") => void;
@@ -56,6 +57,8 @@ interface SidebarProps {
   setBearerToken: (token: string) => void;
   headerName?: string;
   setHeaderName?: (name: string) => void;
+  customHeaders: [string, string][];
+  setCustomHeaders: (headers: [string, string][]) => void;
   onConnect: () => void;
   onDisconnect: () => void;
   stdErrNotifications: StdErrNotification[];
@@ -83,6 +86,8 @@ const Sidebar = ({
   setBearerToken,
   headerName,
   setHeaderName,
+  customHeaders,
+  setCustomHeaders,
   onConnect,
   onDisconnect,
   stdErrNotifications,
@@ -101,6 +106,7 @@ const Sidebar = ({
   const [copiedServerEntry, setCopiedServerEntry] = useState(false);
   const [copiedServerFile, setCopiedServerFile] = useState(false);
   const { toast } = useToast();
+  const [showCustomHeaders, setShowCustomHeaders] = useState(false);
 
   // Reusable error reporter for copy actions
   const reportError = useCallback(
@@ -213,6 +219,22 @@ const Sidebar = ({
     }
   }, [generateMCPServerFile, toast, reportError]);
 
+  const removeCustomHeader = (index: number) => {
+    const newHeaders = [...customHeaders];
+    newHeaders.splice(index, 1);
+    setCustomHeaders(newHeaders);
+  };
+
+  const updateCustomHeader = (index: number, field: 'key' | 'value', value: string) => {
+    const newArr = [...customHeaders];
+    const [oldKey, oldValue] = newArr[index];
+    const newTuple: [string, string] = field === 'key'
+        ? [value, oldValue]
+        : [oldKey, value];
+    newArr[index] = newTuple;
+    setCustomHeaders(newArr);
+  };
+
   return (
     <div className="w-80 bg-card border-r border-border flex flex-col h-full">
       <div className="flex items-center justify-between p-4 border-b border-gray-200 dark:border-gray-800">
@@ -720,6 +742,62 @@ const Sidebar = ({
               </>
             )}
           </div>
+
+          <div className="space-y-2">
+            <Button
+              variant="outline"
+              onClick={() => setShowCustomHeaders(!showCustomHeaders)}
+              className="flex items-center w-full"
+              data-testid="custom-headers-button"
+              aria-expanded={showCustomHeaders}
+            >
+              {showCustomHeaders ? (
+                <ChevronDown className="w-4 h-4 mr-2" />
+              ) : (
+                <ChevronRight className="w-4 h-4 mr-2" />
+              )}
+              Custom Headers
+            </Button>
+            {showCustomHeaders && (
+              <div className="space-y-2">
+                {customHeaders.map((header, index) => (
+                  <div key={index} className="space-y-2">
+                    <label className="text-sm font-medium">Header Name</label>
+                    <Input
+                      placeholder="Header Name"
+                      value={header[0]}
+                      onChange={(e) => updateCustomHeader(index, 'key', e.target.value)}
+                      className="font-mono"
+                    />
+                    <label className="text-sm font-medium">Header Value</label>
+                    <Input
+                      placeholder="Header Value"
+                      value={header[1]}
+                      onChange={(e) => updateCustomHeader(index, 'value',  e.target.value)}
+                      className="font-mono"
+                    />
+                    <Button
+                      variant="destructive"
+                      size="sm"
+                      onClick={() => removeCustomHeader(index)}
+                      className="w-full"
+                    >
+                      Remove Header
+                    </Button>
+                  </div>
+                ))}
+                <Button
+                  variant="outline"
+                  className="w-full mt-2"
+                  onClick={() => {
+                    setCustomHeaders([ ...customHeaders, ["", ""]]);
+                  }}
+                >
+                  Add Custom Header
+                </Button>
+              </div>
+            )}
+          </div>
         </div>
       </div>
       <div className="p-4 border-t">

client/src/components/__tests__/Sidebar.test.tsx

@@ -31,32 +31,36 @@ Object.defineProperty(navigator, "clipboard", {
 // Setup fake timers
 jest.useFakeTimers();
 
-describe("Sidebar Environment Variables", () => {
+const defaultProps = {
-  const defaultProps = {
+  connectionStatus: "disconnected" as const,
-    connectionStatus: "disconnected" as const,
+  transportType: "stdio" as const,
-    transportType: "stdio" as const,
+  setTransportType: jest.fn(),
-    setTransportType: jest.fn(),
+  command: "",
-    command: "",
+  setCommand: jest.fn(),
-    setCommand: jest.fn(),
+  args: "",
-    args: "",
+  setArgs: jest.fn(),
-    setArgs: jest.fn(),
+  sseUrl: "",
-    sseUrl: "",
+  setSseUrl: jest.fn(),
-    setSseUrl: jest.fn(),
+  env: {},
-    env: {},
+  setEnv: jest.fn(),
-    setEnv: jest.fn(),
+  bearerToken: "",
-    bearerToken: "",
+  setBearerToken: jest.fn(),
-    setBearerToken: jest.fn(),
+  headerName: "",
-    onConnect: jest.fn(),
+  setHeaderName: jest.fn(),
-    onDisconnect: jest.fn(),
+  customHeaders: [],
-    stdErrNotifications: [],
+  setCustomHeaders: jest.fn(),
-    clearStdErrNotifications: jest.fn(),
+  onConnect: jest.fn(),
-    logLevel: "info" as const,
+  onDisconnect: jest.fn(),
-    sendLogLevelRequest: jest.fn(),
+  stdErrNotifications: [],
-    loggingSupported: true,
+  clearStdErrNotifications: jest.fn(),
-    config: DEFAULT_INSPECTOR_CONFIG,
+  logLevel: "debug" as const,
-    setConfig: jest.fn(),
+  sendLogLevelRequest: jest.fn(),
-  };
+  loggingSupported: false,
+  config: DEFAULT_INSPECTOR_CONFIG,
+  setConfig: jest.fn(),
+};
 
+describe("Sidebar Environment Variables", () => {
   const renderSidebar = (props = {}) => {
     return render(
       <TooltipProvider>
@@ -870,3 +874,79 @@ describe("Sidebar Environment Variables", () => {
     });
   });
 });
+
+describe("Sidebar", () => {
+  it("renders", () => {
+    render(<Sidebar {...defaultProps} />);
+    expect(screen.getByText("MCP Inspector")).toBeInTheDocument();
+  });
+
+  it("shows connect button when disconnected", () => {
+    render(<Sidebar {...defaultProps} />);
+    expect(screen.getByText("Connect")).toBeInTheDocument();
+  });
+
+  it("shows disconnect button when connected", () => {
+    render(
+      <Sidebar
+        {...defaultProps}
+        connectionStatus="connected"
+        customHeaders={[]}
+        setCustomHeaders={jest.fn()}
+      />,
+    );
+    expect(screen.getByText("Disconnect")).toBeInTheDocument();
+  });
+
+  it("shows reconnect button when connected", () => {
+    render(
+      <Sidebar
+        {...defaultProps}
+        connectionStatus="connected"
+        transportType="sse"
+        customHeaders={[]}
+        setCustomHeaders={jest.fn()}
+      />,
+    );
+    expect(screen.getByText("Reconnect")).toBeInTheDocument();
+  });
+
+  it("shows restart button when connected with stdio transport", () => {
+    render(
+      <Sidebar
+        {...defaultProps}
+        connectionStatus="connected"
+        transportType="stdio"
+        customHeaders={[]}
+        setCustomHeaders={jest.fn()}
+      />,
+    );
+    expect(screen.getByText("Restart")).toBeInTheDocument();
+  });
+
+  it("shows environment variables section when stdio transport is selected", () => {
+    render(
+      <Sidebar
+        {...defaultProps}
+        env={{ NEW_KEY: "new_value" }}
+        customHeaders={[]}
+        setCustomHeaders={jest.fn()}
+      />,
+    );
+    const envButton = screen.getByText("Environment Variables");
+    expect(envButton).toBeInTheDocument();
+  });
+
+  it("shows configuration section", () => {
+    render(
+      <Sidebar
+        {...defaultProps}
+        config={DEFAULT_INSPECTOR_CONFIG}
+        customHeaders={[]}
+        setCustomHeaders={jest.fn()}
+      />,
+    );
+    const configButton = screen.getByText("Configuration");
+    expect(configButton).toBeInTheDocument();
+  });
+});

client/src/lib/hooks/useConnection.ts

@@ -54,6 +54,7 @@ interface UseConnectionOptions {
   env: Record<string, string>;
   bearerToken?: string;
   headerName?: string;
+  customHeaders?: [string, string][];
   config: InspectorConfig;
   onNotification?: (notification: Notification) => void;
   onStdErrNotification?: (notification: Notification) => void;
@@ -71,6 +72,7 @@ export function useConnection({
   env,
   bearerToken,
   headerName,
+  customHeaders,
   config,
   onNotification,
   onStdErrNotification,
@@ -287,7 +289,9 @@ export function useConnection({
     try {
       // Inject auth manually instead of using SSEClientTransport, because we're
       // proxying through the inspector server first.
-      const headers: HeadersInit = {};
+      const headers = new Headers(customHeaders||[]);
+
+      //const headers: HeadersInit = [  ...customHeaders||[] ];
 
       // Create an auth provider with the current server URL
       const serverAuthProvider = new InspectorOAuthClientProvider(sseUrl);
@@ -297,7 +301,7 @@ export function useConnection({
         bearerToken || (await serverAuthProvider.tokens())?.access_token;
       if (token) {
         const authHeaderName = headerName || "Authorization";
-        headers[authHeaderName] = `Bearer ${token}`;
+        headers.set(authHeaderName, `Bearer ${token}`);
       }
 
       // Create appropriate transport

client/tsconfig.app.json

@@ -25,7 +25,7 @@
     "noUnusedParameters": true,
     "noFallthroughCasesInSwitch": true,
     "resolveJsonModule": true,
-    "types": ["jest", "@testing-library/jest-dom", "node"]
+    "types": ["jest", "@testing-library/jest-dom", "node", "react", "react-dom"]
   },
   "include": ["src"]
 }

server/src/index.ts

@@ -21,7 +21,14 @@ import { findActualExecutable } from "spawn-rx";
 import mcpProxy from "./mcpProxy.js";
 import { randomUUID } from "node:crypto";
 
-const SSE_HEADERS_PASSTHROUGH = ["authorization"];
+const SSE_HEADERS_PASSTHROUGH = [
+  "authorization",
+  "x-api-key",
+  "x-custom-header",
+  "x-auth-token",
+  "x-request-id",
+  "x-correlation-id"
+];
 const STREAMABLE_HTTP_HEADERS_PASSTHROUGH = [
   "authorization",
   "mcp-session-id",