api.go

package main

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

const (
	url = "http://dummy.restapiexample.com/api/v1/employees"
)

// Employee is the structure which contains the details of an employee
type Employee struct {
	ID             string `json:"id"`
	EmployeeName   string `json:"employee_name"`
	EmployeeSalary string `json:"employee_salary"`
	EmployeeAge    string `json:"employee_age"`
	ProfileImage   string `json:"profile_image"`
}

// EmployeeResponse structure mirrors the JSON response from the endpoint
type EmployeeResponse struct {
	Status string     `json:"status"`
	Data   []Employee `json:"data"`
}

// CallAPI method calls a sample REST API will returns JSON response
func CallAPI() {

	resp, err := http.Get(url)
	if err != nil {
		// Some error occured
		log.Panicln(err)
	}

	defer resp.Body.Close()

	unStructuredJSON(resp)
	structuredJSON(resp)

}

// structuredJSON method parses the structured JSON returned from the response
// Decode JSON data to struct
// Structure of JSON data can be found here: http://dummy.restapiexample.com/api/v1/employees
func structuredJSON(resp *http.Response) {

	// // Method 1: [not ideal] Using ioutil.ReadAll
	// var employeeResponse EmployeeResponse
	// body, err := ioutil.ReadAll(resp.Body)
	// if err != nil {
	// 	fmt.Println(err)
	// }

	// json.Unmarshal([]byte(body), &employeeResponse)
	// fmt.Println("Status = ", employeeResponse.Data[0].EmployeeName)

	// Method 2: [Ideal way] Using NewDecoder
	var response EmployeeResponse
	if err := json.NewDecoder(resp.Body).Decode(&response); err != nil {
		log.Fatalln(err)
	}
	for _, employee := range response.Data {

		fmt.Printf("Name: %s\t\tSalary: %s\n", employee.EmployeeName, employee.EmployeeSalary)

	}

}

// unStructuredJSON method parses the unstructured JSON returned from the response
// Create a Map to store the JSON response
// Use "json.Unmarshal" and "type assertion" to read the reponse
func unStructuredJSON(resp *http.Response) {

	// Output: array of map[employee_age:61 employee_name:Tiger Nixon employee_salary:320800 id:1 profile_image:]
	// Type: []interface {}
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		fmt.Println(err)
	}

	// Returns the status of the response
	fmt.Printf("Response Status = %s\n", resp.Status)

	var result map[string]interface{}
	json.Unmarshal([]byte(body), &result)

	status := result["status"]
	fmt.Println("Response Status: ", status)

	// Output: array of map[employee_age:61 employee_name:Tiger Nixon employee_salary:320800 id:1 profile_image:]
	// Type: []interface {}
	data := result["data"]

	// Use Type assertion to fetch the value of data
	for _, employee := range data.([]interface{}) {

		// Output: map[employee_age:64 employee_name:Paul Byrd employee_salary:725000 id:17 profile_image:]
		// Type: map[string]interface{}
		// fmt.Println(employee)

		// Print Employee name and salary
		details := employee.(map[string]interface{})
		fmt.Printf("Name: %s\t\tSalary: %s\n", details["employee_name"], details["employee_salary"])

	}

}