Convert List Objects to/from JSON in GoLang RESTful Web API

Install Libraries

Make sure Git is installed on your machine and in your system’s PATH. Install the packages to your $GOPATH with the go tool from shell:

$ go get -u github.com/gorilla/mux
$ go get -u github.com/gorilla/handlers

Create Entity

Create new folder named src. In src folder, create new folder named entities. In entities folder, create new file named product.entity.go as below:

package entities

type Product struct {
	Id       string  `json:"id"`
	Name     string  `json:"name"`
	Price    float64 `json:"price"`
	Quantity int     `json:"quantity"`
	Status   bool    `json:"status"`
}

Web APIs

In src folder, create new folder named apis. In this folder, create new web api as below:

Product API

In apis folder, create new folder named productapi. In productapi folder, create new go file named product.api.go as below:

package productapi

import (
	"encoding/json"
	"entities"
	"net/http"
)

func FindAll(response http.ResponseWriter, request *http.Request) {
	products := []entities.Product{
		entities.Product{
			Id:       "p01",
			Name:     "name 1",
			Price:    4.5,
			Quantity: 10,
			Status:   true,
		},
		entities.Product{
			Id:       "p02",
			Name:     "name 2",
			Price:    11,
			Quantity: 2,
			Status:   false,
		},
		entities.Product{
			Id:       "p03",
			Name:     "name 3",
			Price:    16,
			Quantity: 22,
			Status:   true,
		},
	}
	respondWithJSON(response, http.StatusOK, products)
}

func respondWithJSON(response http.ResponseWriter, statusCode int, data interface{}) {
	result, _ := json.Marshal(data)
	response.Header().Set("Content-Type", "application/json")
	response.WriteHeader(statusCode)
	response.Write(result)
}

Structure of Project

Run Application

In src folder, create new file named main.go as below and use go run main.go command to run program:

package main

import (
	"apis/productapi"
	"fmt"
	"net/http"

	"github.com/gorilla/mux"
)

func main() {
	router := mux.NewRouter()

	router.HandleFunc("/api/product/findall", productapi.FindAll).Methods("GET")

	err := http.ListenAndServe(":3000", router)
	if err != nil {
		fmt.Println(err)
	}
}

Test Web API

Use PostMan Tool test web api with url: http://localhost:3000/api/product/findall