We’ll explore how to make an HTTP POST request in Go. We will make a POST request to an endpoint with a JSON body and display the results on the console.
The endpoint will accept id, title, body, userId and create a new post.
Create a new folder called http-request.
mkdir http-request
cd http-request
touch main.go
Open the main.go and import the necessary packages.
package main
import (
"bytes"
"encoding/json"
"fmt"
"net/http"
)
Create a struct that models the data received from the API.
type Post struct {
Id int `json:"id"`
Title string `json:"title"`
Body string `json:"body"`
UserId int `json:"userId"`
}
Create a POST request using the method http.NewRequest.
func main() {
// HTTP endpoint
posturl := "https://jsonplaceholder.typicode.com/posts"
// JSON body
body := []byte(`{
"title": "Post title",
"body": "Post description",
"userId": 1
}`)
// Create a HTTP post request
r, err := http.NewRequest("POST", posturl, bytes.NewBuffer(body))
if err != nil {
panic(err)
}
}
Set the HTTP request header.
r.Header.Add("Content-Type", "application/json")
Create a client and make the post request using the method client.Do
client := &http.Client{}
res, err := client.Do(r)
if err != nil {
panic(err)
}
defer res.Body.Close()
Let's decode the JSON response using json.NewDecoder function that takes in the response body and a decode function that takes in a variable of type Post.
post := &Post{}
derr := json.NewDecoder(res.Body).Decode(post)
if derr != nil {
panic(derr)
}
Panic if the HTTP status code not equals to 201.
if res.StatusCode != http.StatusCreated {
panic(res.Status)
}
Finally, print the newly created post on the console.
fmt.Println("Id:", post.Id)
fmt.Println("Title:", post.Title)
fmt.Println("Body:", post.Body)
fmt.Println("UserId:", post.UserId)
Here is the complete working code.
package main
import (
"bytes"
"encoding/json"
"fmt"
"net/http"
)
type Post struct {
Id int `json:"id"`
Title string `json:"title"`
Body string `json:"body"`
UserId int `json:"userId"`
}
func main() {
posturl := "https://jsonplaceholder.typicode.com/posts"
body := []byte(`{
"title": "Post title",''
"body": "Post description",
"userId": 1
}`)
r, err := http.NewRequest("POST", posturl, bytes.NewBuffer(body))
if err != nil {
panic(err)
}
r.Header.Add("Content-Type", "application/json")
client := &http.Client{}
res, err := client.Do(r)
if err != nil {
panic(err)
}
defer res.Body.Close()
post := &Post{}
derr := json.NewDecoder(res.Body).Decode(post)
if derr != nil {
panic(derr)
}
if res.StatusCode != http.StatusCreated {
panic(res.Status)
}
fmt.Println("Id:", post.Id)
fmt.Println("Title:", post.Title)
fmt.Println("Body:", post.Body)
fmt.Println("UserId:", post.UserId)
}
I hope you found this article insightful.
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