main.go

package main

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

	"github.com/gorilla/mux"
)

// Image type containing an ID, and defining JSON encoding
type Image struct {
	ID string `json:"id"`
}

var images []Image

// Function that will handle the POST requests made on /endpoint
// It adds an image with input ID in the DataBase
func postFunction(w http.ResponseWriter, r *http.Request) {
	// Cast input request to Image
	var image Image
	_ = json.NewDecoder(r.Body).Decode(&image)
	log.Println("Posting Image with ID = ", image.ID, " in my fake database")

	// Add it in the Database
	images = append(images, image)
}

// Function that will handle the GET requests made on /endpoint
// It looks up the input ID in the database, and returns it if it exists
func getFunction(w http.ResponseWriter, r *http.Request) {
	w.WriteHeader(http.StatusOK)

	// Cast input request to Image
	var image Image
	_ = json.NewDecoder(r.Body).Decode(&image)

	// Go through images database, and return (encode in JSON) image
	var result Image
	for _, item := range images {
		if item.ID == image.ID {
			log.Println("Image with ID = ", image.ID, " found in database")
			result = item
			break
		}
	}

	json.NewEncoder(w).Encode(result)
}

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

	// Set up router endpoints
	router.Methods("POST").Path("/endpoint").HandlerFunc(postFunction)
	router.Methods("GET").Path("/endpoint").HandlerFunc(getFunction)

	// Listen on port 8080
	log.Fatal(http.ListenAndServe(":8080", router))
}