Merge pull request #11 from IVainqueur/main

feat: add support for per-request host override in REST API tester

Author: dkmaker

src/index.ts

@@ -36,6 +36,7 @@ interface EndpointArgs {
   endpoint: string;
   body?: any;
   headers?: Record<string, string>;
+  host?: string;
 }
 
 interface ValidationResult {
@@ -133,6 +134,24 @@ const isValidEndpointArgs = (args: any): args is EndpointArgs => {
       `To test a different base URL, update the REST_BASE_URL environment variable.`
     );
   }
+  // Validate .host if present
+  if (args.host !== undefined) {
+    try {
+      const url = new URL(args.host);
+      if (!/^https?:$/.test(url.protocol)) {
+        throw new Error();
+      }
+      // Remove trailing slash if present
+      if (url.pathname.endsWith('/') && url.pathname !== '/') {
+        url.pathname = url.pathname.replace(/\/+$/, '');
+        args.host = url.origin + url.pathname;
+      } else {
+        args.host = url.origin + url.pathname;
+      }
+    } catch (e) {
+      throw new McpError(ErrorCode.InvalidParams, `Invalid host format. The 'host' argument must be a valid URL starting with http:// or https://, e.g. "https://example.com" or "http://localhost:3001/api/v1". Received: "${args.host}"`);
+    }
+  }
 
   return true;
 };
@@ -353,10 +372,11 @@ class RestTester {
       // Ensure endpoint starts with / and remove any trailing slashes
       const normalizedEndpoint = `/${request.params.arguments.endpoint.replace(/^\/+|\/+$/g, '')}`;
 
+      const fullUrl = `${request.params.arguments.host || process.env.REST_BASE_URL}${normalizedEndpoint}`;
       // Initialize request config
       const config: AxiosRequestConfig = {
           method: request.params.arguments.method as Method,
-          url: normalizedEndpoint,
+          url: fullUrl,
           headers: {},
         };
 
@@ -398,7 +418,6 @@ class RestTester {
         const startTime = Date.now();
         const response = await this.axiosInstance.request(config);
         const endTime = Date.now();
-        const fullUrl = `${process.env.REST_BASE_URL}${normalizedEndpoint}`;
 
         // Determine auth method used
         let authMethod = 'none';

src/resources/examples.md

@@ -1,24 +1,29 @@
 # REST API Testing Examples
 
-⚠️ IMPORTANT: Only provide the endpoint path - do not include full URLs. Your path will be automatically resolved to the full URL.
+⚠️ IMPORTANT:
+- Only provide the endpoint path in the `endpoint` argument—do not include full URLs. Your path will be automatically resolved to the full URL using the configured base URL or the optional `host` argument.
+- To override the base URL for a single request, use the optional `host` argument. This must be a valid URL starting with `http://` or `https://`, and may include a path (trailing slashes will be removed).
 
 For example, if the base URL is `http://localhost:3000`:
 ✅ Correct: `"/api/users"` → Resolves to: `http://localhost:3000/api/users`
 ❌ Incorrect: `"http://localhost:3000/api/users"` or `"www.example.com/api/users"`
 
+If you use a `host` argument:
+✅ Correct: `"host": "https://api.example.com/v1", "endpoint": "/users"` → Resolves to: `https://api.example.com/v1/users`
+
 ## Basic GET Request
 ```typescript
 use_mcp_tool('rest-api', 'test_request', {
   "method": "GET",
-  "endpoint": "/users"  // Will be appended to REST_BASE_URL
+  "endpoint": "/users"  // Will be appended to REST_BASE_URL or 'host' if provided
 });
 ```
 
 ## GET with Query Parameters
 ```typescript
 use_mcp_tool('rest-api', 'test_request', {
   "method": "GET",
-  "endpoint": "/users?role=admin&status=active"
+  "endpoint": "/users?role=admin&status=active" // Always a path, not a full URL
 });
 ```
 
@@ -66,8 +71,24 @@ use_mcp_tool('rest-api', 'test_request', {
 });
 ```
 
+## Using the Optional `host` Argument
+You can override the default base URL for a single request by providing a `host` argument. This must be a valid URL starting with `http://` or `https://`, and may include a path (trailing slashes will be removed).
+
+```typescript
+use_mcp_tool('rest-api', 'test_request', {
+  "method": "GET",
+  "endpoint": "/users",
+  "host": "https://api.example.com/v1" // The request will go to https://api.example.com/v1/users
+});
+```
+
+- The `host` argument must include the protocol (http or https).
+- If a path is included, any trailing slash will be removed.
+- If `host` is invalid, you will receive a clear error message.
+- The `endpoint` argument must always be a path, never a full URL.
+
 ## Changing Base URL
-If you need to test against a different base URL, update the base URL configuration rather than including the full URL in the endpoint parameter.
+If you need to test against a different base URL for all requests, update the base URL configuration rather than including the full URL in the endpoint parameter. For a single request, use the `host` argument as shown above.
 
 Example:
 ```bash
@@ -78,3 +99,6 @@ Example:
 # 1. Update the base URL configuration to: https://api.example.com
 # 2. Then use just the path:
 ✅ "endpoint": "/users"  # This will resolve to: https://api.example.com/users
+# Or, for a single request:
+✅ "host": "https://api.example.com", "endpoint": "/users"  # This will resolve to: https://api.example.com/users
+```