HTTP Server

Last modified: 19 December 2024

To create an HTTP server program in Go, you need to create a few files: main.go for the main logic and optionally, a server.go file for the server functionality. Here is a step-by-step guide:

Step 1: Initialize the Go Module

First, create a new directory for your project and initialize the Go module.

mkdir httpserver
cd httpserver
go mod init github.com/username/httpserver

Step 2: Create the server.go File

Create a server.go file to handle the HTTP server functionality.

// server.go
package main

import (
    "fmt"
    "net/http"
)

// handler is a simple HTTP handler function.
func handler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "Hello, World!")
}

// StartServer starts the HTTP server on the specified port.
func StartServer(port string) error {
    http.HandleFunc("/", handler)
    return http.ListenAndServe(":"+port, nil)
}

Step 3: Create the main.go File

Create a main.go file to use the server functionality.

// main.go
package main

import (
    "fmt"
    "os"
)

func main() {
    if len(os.Args) != 2 {
        fmt.Println("Usage: httpserver <port>")
        os.Exit(1)
    }

    port := os.Args[1]
    fmt.Printf("Starting server on port %s...\n", port)
    if err := StartServer(port); err != nil {
        fmt.Printf("Server failed: %v\n", err)
        os.Exit(1)
    }
}

Step 4: Run the Program

Run the program using the go run command.

go run main.go 8080

This will start the HTTP server on port 8080. You can access it by navigating to http://localhost:8080 in your web browser.