Manoj Karthick

In this part, we will create a URL Shortener consuming the is.gd API. This API returns a response in JSON Format.

In the previous post, we looked at how to create a Command line URL shortener by consuming the tinyURL API.
If you missed it, check it out here.

So, we will be learning:

• How to consume JSON APIs in Golang
• How to parse JSON in Golang

First we need to create a struct that represents the
JSON format that we get from the API.

API Endpoint: https://is.gd/create.php?format=json&url=<url_to_be_shortened>

JSON Format returned:

{ "shorturl": "https://is.gd/MOgh5q" }

I recommend using JSON to Go to convert your JSON to corresponding Go struct automatically.

//This is the JSON format we get from is.gd
type AutoGenerated struct {
	Shorturl string `json:"shorturl"`
}

We create a New Request here using the http.NewRequest method. Alternatively, you can also use the http.Get method.
The method takes three arguments, type of request, URL and one argument of type io.Reader.

request, err := http.NewRequest("GET", getReqURL, nil)
	if err != nil {
		log.Fatal("NewRequest: ", err)
		return
	}

	client := &http.Client{}

	response, err := client.Do(request)
	if err != nil {
		log.Fatal("Do: ", err)
		return
	}

Initialize a HTTP Client and make the GET call. Store the response in the variable response. Exit if there was any error.

Use defer response.Body.Close() to close the stream once we are done reading the response.

err := json.NewDecoder(response.Body).Decode(&result)

Use the json.NewDecoder method to decode the response and store in the variable result using the Decode method.

NOTE: All exported methods must begin with a Capital letter. Also, Don't forget to import the encoding/json package.

fmt.Println("Shortened URL is: ", result.Shorturl)

Then Print the Shortened URL to the console!

Full code:

Happy Coding!