How can I display the JSON response from the API in Go? - json

Question

I'm invoking a small API that gives back a JSON response with a Todo object. How can I display that in my Go web server? Right now, all that's displaying is 'Todo', which I hard-coded. How can that be replaced by the API JSON response?
Here is the code:
package main
import (
"fmt"
"io/ioutil"
"log"
"net/http"
"os"
)
// Todo Structure
type Todo struct {
userID int
id int
title string
completed bool
}
func main() {
http.HandleFunc("/hello", func(w http.ResponseWriter, r *http.Request) {
fmt.Fprintf(w, "<h1>Todo</h1>")
})
response, err := http.Get("http://jsonplaceholder.typicode.com/todos/1")
if err != nil {
fmt.Print(err.Error())
os.Exit(1)
}
responseData, err := ioutil.ReadAll(response.Body)
if err != nil {
log.Fatal(err)
}
fmt.Println(string(responseData))
if err := http.ListenAndServe(":8080", nil); err != nil {
log.Fatal(err)
}
}

Answer 1

You have to write a function delegated to retrieve the data from the external website. Than use the http.HandleFunc in order to expose the method at your endpoint, here an example:
package main
import (
"fmt"
"io/ioutil"
"log"
"net/http"
"os"
)
// Todo Structure
type Todo struct {
userID int
id int
title string
completed bool
}
func main() {
http.HandleFunc("/hello", func(w http.ResponseWriter, r *http.Request) {
fmt.Fprintf(w, callHTTP())
})
if err := http.ListenAndServe(":8080", nil); err != nil {
log.Fatal(err)
}
}
func callHTTP() string {
var (
response *http.Response
err error
responseData []byte
)
if response, err = http.Get("http://jsonplaceholder.typicode.com/todos/1"); err != nil {
fmt.Println(err.Error())
os.Exit(1)
}
if responseData, err = ioutil.ReadAll(response.Body); err != nil {
log.Fatal(err)
}
ret := string(responseData)
fmt.Println(ret)
return ret
}
Note:
Avoid to use the default http client in production. You can try some HTTP framework like GIN. I prefer fasthttp, here you can view some code as example: https://github.com/alessiosavi/StreamingServer