Golang is a very popular programming language. Its fast development speed and high code running efficiency are very suitable for the development of web applications. This article will introduce how to use Golang to build an HTTP server.
1. Install Golang
Before we start, we need to install Golang first. You can download the Golang installation package from the official website and install it on your computer. After installation, use the command line tool to verify whether Golang is installed successfully. You can enter the following command:
$ go version
If the version number of Golang is output, it means that Golang is installed successfully.
2. Build HTTP server
Now we start to build HTTP server. First we need to save the following code as a file named server.go.
package main import ( "fmt" "net/http" ) func homeHandler(w http.ResponseWriter, r *http.Request) { fmt.Fprintf(w, "Hello, Golang!") } func main() { http.HandleFunc("/", homeHandler) http.ListenAndServe(":8000", nil) }
Through the above code, we have implemented a very simple HTTP server, which can respond to HTTP requests on the local port 8000 and send a string "Hello, Golang!" to the client.
Now we can compile and start this server through the following commands.
$ go run server.go
Execute the above code in the command line tool. If no error message appears, we can access "localhost:8000" through the browser and see the "Hello, Golang!" string appearing in in the browser.
3. Extending the HTTP server
Of course, the above code only implements a very basic HTTP server, which cannot meet our needs. Below we introduce some common operations to extend the HTTP server.
We can register the HTTP request processing function through the HandleFunc function of the http package. For example, the following code can process the HTTP GET request and output it to the browser "Hello, World!".
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) { fmt.Fprintf(w, "Hello, World!") })
We can obtain the parameters in the HTTP request through the FormValue method of the Request object. For example, we can parse the "username" and "password" parameters with the following code and output their values to the browser.
http.HandleFunc("/login", func(w http.ResponseWriter, r *http.Request) { r.ParseForm() username := r.FormValue("username") password := r.FormValue("password") fmt.Fprintf(w, "Username: %s, Password: %s", username, password) })
We can use the FileServer function of the http package to process static files. For example, the following code can output all files located in the current directory on the local port 8000.
http.Handle("/", http.FileServer(http.Dir(".")))
When we access "localhost:8000" through the browser, we can see all the files appear in the browser.
4. Summary
Through the introduction of this article, we have learned how to use Golang to build an HTTP server. Although this article only introduces some of the most basic operations, they are enough for us to implement a simple web application. In the future learning process, we can implement richer web applications by using other libraries and frameworks.
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