How to Make HTTP Requests in Golang

In our previous tutorial, we have explained about Channels in Golang. In this tutorial, we will explain how to make HTTP Requests in Golang.

There are net/http package is available to make HTTP requests. We just need tp import the package in our script and can use GET, POST, PostForm HTTP functions to make requests.

So here in this tutorial we will explain how to make GET, POST, PostForm HTTP requests in Golang.

Also, read:

Creating REST API with Golang

We will cover following in this tutorial:

HTTP GET Request
HTTP POST Request
HTTP Posting Form Data

1. HTTP GET Request

We can make the simple HTTP GET request using http.Get function. We will import the net/http package and use http.Get function to make request.

Here in this example, we will make the HTTP GET request and get response. We will read the response and display response output.

package main

import (
    "fmt"
    "io/ioutil"
    "net/http"
)

func main() {

    response, err := http.Get("https://api.github.com/users/mojombo")
    if err != nil {
        print(err)
    }  
	
    defer response.Body.Close()
	
    body, err := ioutil.ReadAll(response.Body)
    if err != nil {
        print(err)
    }
    
    fmt.Print(string(body))
	
}

Output:

{
	"login":"mojombo",
	"id":1,
	"node_id":"MDQ6VXNlcjE=",
	"avatar_url":"https://avatars0.githubusercontent.com/u/1?v=4",
	"gravatar_id":"",
	"url":"https://api.github.com/users/mojombo",
	"html_url":"https://github.com/mojombo",
	"followers_url":"https://api.github.com/users/mojombo/followers",
	"following_url":"https://api.github.com/users/mojombo/following{/other_user}",
	"gists_url":"https://api.github.com/users/mojombo/gists{/gist_id}",
	"starred_url":"https://api.github.com/users/mojombo/starred{/owner}{/repo}",
	"subscriptions_url":"https://api.github.com/users/mojombo/subscriptions",
	"organizations_url":"https://api.github.com/users/mojombo/orgs",
	"repos_url":"https://api.github.com/users/mojombo/repos",
	"events_url":"https://api.github.com/users/mojombo/events{/privacy}",
	"received_events_url":"https://api.github.com/users/mojombo/received_events",
	"type":"User",
	"site_admin":false,
	"name":"Tom Preston-Werner",
	"company":null,
	"blog":"http://tom.preston-werner.com",
	"location":"San Francisco",
	"email":null,
	"hireable":null,
	"bio":null,
	"twitter_username":null,
	"public_repos":61,
	"public_gists":62,
	"followers":22047,
	"following":11,
	"created_at":"2007-10-20T05:24:19Z",
	"updated_at":"2020-07-07T16:50:36Z"
}

2. HTTP POST Request

We need to import the net/http package for making HTTP request. Then we can use the http.Post function to make HTTP POST requests.

Here in this example, we will make HTTP POST request to https://httpbin.org/post website and send the JSON payload. We will marsh marshaling a map and will get the []byte if successful request. We will handle the error and then make POST request using http.Post. Then we will read the response and display.

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
)

func main() {
	requestBody, error := json.Marshal(map[string]string{
		"username": "webdamn go",
		"email":    "webdamngo@gmail.com",
	})

	if error != nil {
		print(error)
	}
	
	response, error := http.Post("https://httpbin.org/post",
		"application/json", bytes.NewBuffer(requestBody))
	if error != nil {
		print(error)
	}
	
	defer response.Body.Close()
	body, error := ioutil.ReadAll(response.Body)
	if error != nil {
		print(error)
	}
	
	fmt.Println(string(body))
}

Output:

{
  "args": {},
  "data": "{\"email\":\"webdamngo@gmail.com\",\"username\":\"webdamn go\"}",
  "files": {},
  "form": {},
  "headers": {
    "Accept-Encoding": "gzip",
    "Content-Length": "55",
    "Content-Type": "application/json",
    "Host": "httpbin.org",
    "User-Agent": "Go-http-client/2.0",
    "X-Amzn-Trace-Id": "Root=1-5f13c0b8-5bac0cd4e6ebe3d08489fe24"
  },
  "json": {
    "email": "webdamngo@gmail.com",
    "username": "webdamn go"
  },
  "origin": "47.8.250.54",
  "url": "https://httpbin.org/post"
}

3. HTTP Posting Form Data

We need import the net/http package for making HTTP request to post form data. Then we can use the http.PostForm function to post form data.

Here in this example, we will create form data variable formData is of url.Values type, which is map[string][]string that’s a map type, where each key has a value of []string. For each key, we can have the list of string values. Then we will use the http.PostForm to submit form values to https://httpbin.org/post url and display form data value.

package main

import (
	"encoding/json"
	"log"
	"net/http"
	"net/url"
)

func main() {
	MakeRequest()
}

func MakeRequest() {
	formData := url.Values{
		"name": {"webdamn"},
	}

	response, error := http.PostForm("https://httpbin.org/post", formData)
	if error != nil {
		log.Fatalln(error)
	}

	var result map[string]interface{}
	json.NewDecoder(response.Body).Decode(&result)

	log.Println(result["form"])
}

Output:

2020/07/19 09:29:03 map[name:webdamn]

Conclusion

In this tutorial we have explained how to make HTTP GET, POST requests using Go. We have also explained how to post form data. If you have any queries regarding this tutorial, then please feel free to let me know in the comments section below.

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