Unable to set POST body in a http request - go

Question

Is this not the right way to set POST request body?
data := url.Values{}
data.Set("url", "https://www.google.com/")
client := http.Client{}
r, err := http.NewRequest(http.MethodPost, apiURL, strings.NewReader(data.Encode()))
The code below when executed suggests that no url param was sent in the POST request.
package main
import (
"fmt"
"io/ioutil"
"net/http"
"net/url"
"strings"
)
func doAPICall() {
// curl -XPOST -d 'url=https://www.google.com/' 'https://cleanuri.com/api/v1/shorten'
apiURL := "https://cleanuri.com/api/v1/shorten"
data := url.Values{}
data.Set("url", "https://www.google.com/")
client := http.Client{}
r, err := http.NewRequest(http.MethodPost, apiURL, strings.NewReader(data.Encode()))
if err != nil {
panic(err)
}
resp, err := client.Do(r)
if err != nil {
panic(err)
}
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
panic(err)
}
fmt.Println(string(body))
}
func main() {
doAPICall()
}
Output:-
$ go run .
{"error":"API Error: URL is empty"}
$

Answer 1

The server expects a valid value for the Content-Type request header.
r, err := http.NewRequest(http.MethodPost, apiURL, strings.NewReader(data.Encode()))
if err != nil {
panic(err)
}
r.Header.Set("Content-Type", "application/x-www-form-urlencoded") // <-- add this line
resp, err := client.Do(r)
The server also supports JSON request bodies:
r, err := http.NewRequest(http.MethodPost, apiURL, strings.NewReader(`{"url": "https://www.google.com/"}`))
if err != nil {
panic(err)
}
r.Header.Set("Content-Type", "application/json")
resp, err := http.DefaultClient.Do(r)

Answer 2

You can do something like this
package main
import (
"fmt"
"io/ioutil"
"net/http"
"strings"
)
func main() {
url := "https://cleanuri.com/api/v1/shorten"
payload := strings.NewReader("url=https://www.google.com/")
req, err := http.NewRequest("POST", url, payload)
if err != nil {
fmt.Println(err)
return
}
req.Header.Add("content-type", "application/x-www-form-urlencoded")
req.Header.Add("cache-control", "no-cache")
res, err := http.DefaultClient.Do(req)
if err != nil {
fmt.Println(err)
return
}
defer res.Body.Close()
body, _ := ioutil.ReadAll(res.Body)
fmt.Println(res)
fmt.Println(string(body))
}