Implementing a Basic HTTP Handler in Go

This challenge will guide you through the process of creating a custom HTTP handler function in Go. Understanding how to define and use http.HandlerFunc is fundamental for building any web service or API in Go. You'll learn how to respond to incoming HTTP requests and send back simple text responses.

Problem Description

Your task is to create an http.HandlerFunc that will serve as an endpoint for a simple web server. When a GET request is received at the /hello path, your handler should respond with the text "Hello, World!".

Key Requirements:

• Implement a function that conforms to the http.HandlerFunc signature: func(w http.ResponseWriter, r *http.Request).
• This handler function should only respond to GET requests.
• For GET requests to the /hello path, it should write the string "Hello, World!" to the http.ResponseWriter.
• For any other HTTP method or path, it should return an appropriate HTTP error (e.g., 405 Method Not Allowed or 404 Not Found).

Expected Behavior:

• When a client makes a GET request to /hello, the server should respond with:
  • HTTP Status Code: 200 OK
  • Body: Hello, World!
• When a client makes a POST request to /hello, the server should respond with:
  • HTTP Status Code: 405 Method Not Allowed
  • Body: (Optional, but good practice to include a message like "Method not allowed")
• When a client makes a GET request to /other, the server should respond with:
  • HTTP Status Code: 404 Not Found
  • Body: (Optional, but good practice to include a message like "Not found")

Edge Cases to Consider:

• Requests with methods other than GET to the /hello path.
• Requests to paths other than /hello.

Examples

Example 1:

• Input (Client Request):

  GET /hello HTTP/1.1
  Host: localhost:8080
  

• Output (Server Response):

  HTTP/1.1 200 OK
  Content-Type: text/plain; charset=utf-8
  X-Content-Length: 13
  Date: [Current Date/Time]
  
  Hello, World!
  

• Explanation: The GET request to /hello is handled by your custom HandlerFunc, which correctly writes "Hello, World!" and sets the status to 200 OK.

Example 2:

• Input (Client Request):

  POST /hello HTTP/1.1
  Host: localhost:8080
  

• Output (Server Response):

  HTTP/1.1 405 Method Not Allowed
  Content-Type: text/plain; charset=utf-8
  X-Content-Length: 17
  Date: [Current Date/Time]
  
  Method not allowed
  

• Explanation: The POST request to /hello is not handled by the specific logic for GET requests, so the handler should inform the client that the method is not allowed.

Example 3:

• Input (Client Request):

  GET /goodbye HTTP/1.1
  Host: localhost:8080
  

• Output (Server Response):

  HTTP/1.1 404 Not Found
  Content-Type: text/plain; charset=utf-8
  X-Content-Length: 9
  Date: [Current Date/Time]
  
  Not found
  

• Explanation: The GET request to /goodbye is not the /hello path, so the handler should indicate that the resource was not found.

Constraints

• The Go standard library net/http package must be used.
• No external third-party HTTP routing libraries are allowed.
• The solution should be contained within a single main package.
• The HTTP server should listen on port 8080.

Notes

• Remember to import the net/http and fmt packages.
• You will need to register your http.HandlerFunc with a specific path using http.HandleFunc.
• You will then need to start the HTTP server using http.ListenAndServe.
• Use w.WriteHeader() to set the HTTP status code.
• Use fmt.Fprintln() or w.Write() to write the response body.
• For error responses, consider setting the appropriate Content-Type header.