docs: added usage example in the readme

Author: aDiThYa-808

README.md

@@ -5,9 +5,9 @@
 
 A minimal HTTP server implemented using Go’s net/http package. Implemented to understand how handlers, middleware, concurrency, and context propagation work in Go.
 
-## Features (in the current stage)
+## Features
 ### Endpoints:
-- **`/`**: endpoint that is protected by an authentication middleware. It performs no task other than printing a message. 
+- **`/health`**: Returns OK if server is running. 
 
 - **`/stats`**: endpoint that returns the request metrics like total requests, successful requests and Unauthorized requests in JSON.
 
@@ -16,8 +16,10 @@ For example `http://localhost:4000/work?limit=1000` will compute the first 1000
 
 - **`/upload`**: Recieves the file in the POST request form field. Creates a temporary file with a unique name in the `./uploads` directory using `os.CreateTemp` and copies the file to it using `io.Copy()`. Renames the temp file using os.Rename() with a safe name created by a helper method in the format `./uploads/uuid_originalFileName.extension`. `uuid` is a unique ID generated by `google/uuid` to maintain unique file names. Performs clean up when the function returns.
 
+- **`/download`**: Recieves the file name from the incoming request's `file` query. Checks if the file exists, using `os.Stat()`. If the file exists, it uses `http.ServeFile()` to send the file the client.
+
 ### Middlewares:
-- **`AuthMiddleware()`**: protects the endpoints and returns 401 if the Basic Auth credentials are invalid.
+- **`AuthMiddleware()`**: protects the endpoints and returns 401 if the Basic Auth credentials are invalid. The password has been hardcoded because this is just a practice/learning project and I wanted to focus on other important concepts such as file uploading and downloading.
 
 - **`LoggingMiddleware()`**: logs the request's method, path, timestamp and time taken to complete the request.
 
@@ -42,5 +44,42 @@ For example `http://localhost:4000/work?limit=1000` will compute the first 1000
 
 ---
 
-> # Important Note !
-> **This project is still under development. The README will be updated with new features and endpoints in the coming days.**
+## Usage example
+- **Clone Repository**
+```bash
+git clone https://github.com/aDiThYa-808/golang-http-server.git
+```
+- **Start server**
+```bash 
+go run ./cmd/server
+```
+
+- **Upload file**
+```bash
+curl -X POST http://localhost:4000/upload -F "file=@example.pdf"
+```
+
+- **Download file**
+```bash
+curl -o output.pdf http://localhost:4000/download?file=example.pdf
+```
+
+- **View metrics**
+```bash
+curl -u admin:pass http://localhost:4000/stats
+```
+> Note: the password is hardcoded only because this project was made for learning purpose.
+
+- **Simulate work(compute prime numbers)**
+```bash
+curl http://localhost:4000/work?limit=50000
+```
+
+- **Health check**
+```bash
+curl -u admin:pass http://localhost:4000/health
+```
+
+---
+
+# Thank you