main.go

package main

import (
	"fmt"
	"io"
	"mime/multipart"
	"net/http"
	"os"

	"gocv.io/x/gocv"
	"gocv.io/x/gocv/contrib"
)

func saveFile(file *multipart.FileHeader) error {
	src, err := file.Open()
	if err != nil {
		return err
	}
	defer src.Close()

	dst, err := os.Create("/tmp/" + file.Filename)
	if err != nil {
		return err
	}
	defer dst.Close()

	if _, err = io.Copy(dst, src); err != nil {
		return err
	}

	return nil
}

func detectKeypoints(img gocv.Mat) {
	gray := gocv.NewMat()
	gocv.CvtColor(img, &gray, gocv.ColorBGRToGray)

	sift := contrib.NewSIFT()
	fmt.Printf("Detected keypoints: %d\n", len(sift.Detect(gray)))

	gray.Close()
	sift.Close()
}

func receiveFile(w http.ResponseWriter, r *http.Request) {
	_, header, err := r.FormFile("img")
	if err != nil {
		panic(err)
	}

	if err = saveFile(header); err != nil {
		panic(err)
	}

	fmt.Printf("Received file: %s\n", "/tmp/"+header.Filename)

	img := gocv.IMRead("/tmp/"+header.Filename, gocv.IMReadColor)
	defer img.Close()

	// To make memory consumption faster
	detectKeypoints(img)
	detectKeypoints(img)

	return
}

func main() {
	http.HandleFunc("/upload", receiveFile)
	fmt.Println("Starting server")
	http.ListenAndServe(":8080", nil)
}