Building a web server in Golang

This post is a solution to the "Adam doesn't know routing" problem on Debugg. Visit Debugg at https://debugg.me

What we need here is a simple web server and one route, the / or "root" route, let's say.

There's a built-in package called net/http that can help us here. Open the main.go file, and import the package.

// main.go package main import "net/http" func main() { } 

The official documentation of the package shows an example for the function ListenAndServe, which is just what we need.

// main.go ... func main() { http.ListenAndServe(":8080", nil) } 

which will start an http server on port 8080. Now we need to return "Hello, world!" on the root route. For this we use a HandleFunc and pass it the route path and the handler function.

// main.go ... func helloHandler(w http.ResponseWriter, _ *http.Request) {} func main() { http.HandleFunc("/", helloHandler) http.ListenAndServe(":8080", nil) } 

to return "Hello, World!", we invoke io.WriteString by passing in the ResponseWriter instance and "Hello, World!".

The final file looks as follows

package main import ( "io" "log" "net/http" ) func helloHandler(w http.ResponseWriter, _ *http.Request) { io.WriteString(w, "Hello, World!") } func main() { http.HandleFunc("/", helloHandler) log.Fatal(http.ListenAndServe(":8080", nil)) } 

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