Http Client in Miranda

Here’s an idiomatic Miranda code example demonstrating the concept of an HTTP client:

|| HTTP Client in Miranda

|| Import required libraries
%include "socket.m"
%include "string.m"

|| Function to send an HTTP GET request and return the response
http_get url = response
               where
               (host, path) = parse_url url
               socket = open_connection host 80
               request = "GET " ++ path ++ " HTTP/1.1\r\nHost: " ++ host ++ "\r\n\r\n"
               sent = send_all socket request
               response = recv_all socket
               close_connection socket

|| Helper function to parse a URL into host and path
parse_url url = (host, path)
                where
                parts = split url "/"
                host = hd parts
                path = "/" ++ concat (intersperse "/" (tl parts))

|| Main function to demonstrate HTTP client usage
main = 
    let url = "www.example.com/index.html"
        response = http_get url
    in
    (
        "Response from " ++ url ++ ":\n\n" ++
        take 200 response ++ 
        (if #response > 200 then "..." else "")
    )

|| Run the main function
run = main

This Miranda code demonstrates a basic HTTP client implementation. Here’s an explanation of the code:

1. We start by including necessary libraries for socket operations and string manipulation.

2. The http_get function is the core of our HTTP client. It takes a URL as input and returns the server’s response. It performs these steps:

   • Parses the URL into host and path components
   • Opens a socket connection to the host on port 80 (standard HTTP port)
   • Constructs and sends an HTTP GET request
   • Receives the response from the server
   • Closes the connection

3. The parse_url helper function splits a URL into its host and path components.

4. The main function demonstrates how to use the HTTP client:

   • It defines a URL to fetch
   • Calls http_get to retrieve the response
   • Prints the first 200 characters of the response (or the full response if it’s shorter)

5. The run function is set to main, which is Miranda’s way of specifying the entry point of the program.

To run this Miranda program:

1. Save the code in a file with a .m extension, for example http_client.m.
2. Ensure you have a Miranda interpreter installed.
3. Run the program using the Miranda interpreter:

$ miranda http_client.m

This will execute the run function and display the output.

Note that Miranda is a purely functional language, so this example uses functional programming paradigms. The actual socket operations are assumed to be provided by the hypothetical socket.m library, as Miranda doesn’t have built-in networking capabilities.

This example demonstrates how to create a simple HTTP client in Miranda, showcasing functional programming concepts and Miranda’s syntax while addressing the same core concept as the original Go example.