Hello,
Today, I am going to write small tutorial about basic usage of http.Post method in Golang. Please ignore if there is any mistakes, thank you.
package main
import (
"bytes"
"encoding/json"
"fmt"
"log"
"net/http"
)
// Post holds the post data that we send or receive from the API server.
type Post struct {
ID string `json:"id,omitempty"`
Title string `json:"title"`
Body string `json:"Body"`
UserID string `json:"user_id"`
}
func main() {
// Before we create resource or post on the API server, we need to see the documentation of the REST API we want to use.
// Like what is the URL, version, what are the required fields in the resource object.
// Most of the companies create API docs, it will have examples in different programming languages along with cURL commands.
// Companies also create SDKs in different programming languages.
// Difference between SDK and API: https://addevice.medium.com/difference-between-an-api-and-an-sdk-anyone-can-understand-3a95bf7fc691
// For example Okta to deal with mangement of users, they are having SDK at:https://github.com/okta/okta-sdk-golang
// Let's build response body for the server we want to post or create resource
p := new(Post)
p.Title = "Title"
p.Body = "This is body"
p.UserID = "userID"
// Now we need erializes Post 'p' to JSON
b, err := json.Marshal(p)
if err != nil {
log.Fatalf("Failed to Serialize to JSON from native Go struct type: %v", err)
}
// here http.Post method expects body as 'io.Redear' which should implement Read() method.
// So, bytes package will take care of that.
body := bytes.NewBuffer(b)
// REST APIs means, always think in terms of 'resources'.
// This is good resource: https://www.practical-go-lessons.com/chap-35-build-an-http-client
// This post method uses default http client, so timeout is NOT mentioned.
// Doc of this POST API can be found here: https://jsonplaceholder.typicode.com/guide/.
postURL := "https://jsonplaceholder.typicode.com/posts"
resp, err := http.Post(postURL, "application/json; charset=utf-8", body)
if err != nil {
log.Fatalf("Failed to create resource at: %s and the error is: %v\n", postURL, err)
}
// Always close the response body
defer resp.Body.Close()
// Let us just print the response headers info from the server
log.Printf("Status received from server is: %s", resp.Status)
log.Printf("StatusCode received from server is: %d", resp.StatusCode)
log.Printf("Content Type received from Server is: %s", resp.Header["Content-Type"][0])
// Like I mentioned in my last article,
// we can read the server response to our native Golang type
// as the map data structure is close to JSON, we could use it
// in fact we could use this for most of the wire formats.
data := make(map[string]interface{})
if err := json.NewDecoder(resp.Body).Decode(&data); err != nil {
log.Fatalf("Failed to read response body: %v", err)
}
// Let's print the map data by iterating over it.
// Usually in real usecases we use this response to pass to ther functions.
for key, value := range data {
fmt.Printf("%s: %v\n", key, value)
}
log.Println("We have successfully created resource and read the response from API server.")
}
Thank you.
Top comments (1)
Great post!
Actually, you can use this snippet below instead of using ioutil.ReadAll and json.Unmarshal