func (a *Application) Store(i *image.ImageFile) error {
	con := a.KVStore.Connection()
	defer con.Close()

	err := i.Save()

	if err != nil {
		a.Logger.Fatal(err)
		return err
	}

	a.Logger.Infof("Save thumbnail %s to storage", i.Filepath)

	key := a.WithPrefix(i.Key)

	err = con.Set(key, i.Filepath)

	if err != nil {
		a.Logger.Fatal(err)

		return err
	}

	a.Logger.Infof("Save key %s => %s to kvstore", key, i.Filepath)

	return nil
}

func (a *Application) Store(filepath string, i *image.ImageFile) error {
	con := a.KVStore.Connection()
	defer con.Close()

	err := i.Save()

	if err != nil {
		a.Logger.Fatal(err)
		return err
	}

	a.Logger.Infof("Save thumbnail %s to storage", i.Filepath)

	key := a.WithPrefix(i.Key)

	err = con.Set(key, i.Filepath)

	if err != nil {
		a.Logger.Fatal(err)

		return err
	}

	a.Logger.Infof("Save key %s => %s to kvstore", key, i.Filepath)

	// Write children info only when we actually want to be able to delete things.
	if a.EnableDelete {
		err = con.SetAdd(filepath+":children", key)

		if err != nil {
			a.Logger.Fatal(err)
			return err
		}

		a.Logger.Infof("Put key into set %s:children => %s in kvstore", filepath, key)
	}

	return nil
}

func (a *Application) ImageFileFromRequest(req *Request, async bool, load bool) (*image.ImageFile, error) {
	var file *image.ImageFile = &image.ImageFile{
		Key:     req.Key,
		Storage: a.DestStorage,
		Headers: map[string]string{},
	}
	var err error

	key := a.WithPrefix(req.Key)

	// Image from the KVStore found
	stored, err := gokvstores.String(req.Connection.Get(key))

	file.Filepath = stored

	if stored != "" {
		a.Logger.Infof("Key %s found in kvstore: %s", key, stored)

		if load {
			file, err = image.FromStorage(a.DestStorage, stored)

			if err != nil {
				return nil, err
			}
		}
	} else {
		a.Logger.Infof("Key %s not found in kvstore", key)

		// Image not found from the KVStore, we need to process it
		// URL available in Query String
		if req.URL != nil {
			file, err = image.FromURL(req.URL)
		} else {
			// URL provided we use http protocol to retrieve it
			file, err = image.FromStorage(a.SourceStorage, req.Filepath)
		}

		if err != nil {
			return nil, err
		}

		file, err = a.Engine.Transform(file, req.Operation, req.QueryString)

		if err != nil {
			return nil, err
		}

		file.Filepath = fmt.Sprintf("%s.%s", a.ShardFilename(req.Key), file.Format())
	}

	file.Key = req.Key
	file.Storage = a.DestStorage

	file.Headers["Content-Type"] = file.ContentType()
	file.Headers["ETag"] = req.Key

	if stored == "" {
		if async == true {
			go a.Store(req.Filepath, file)
		} else {
			err = a.Store(req.Filepath, file)
		}
	}

	return file, err
}

func (e *GoImageEngine) TransformGIF(img *imagefile.ImageFile, width int, height int, options *Options, trans Transformation) ([]byte, error) {
	first, err := gif.Decode(bytes.NewReader(img.Source))

	if err != nil {
		return nil, err
	}

	factor := scalingFactorImage(first, width, height)

	if factor > 1 && !options.Upscale {
		return img.Source, nil
	}

	g, err := gif.DecodeAll(bytes.NewReader(img.Source))

	if err != nil {
		return nil, err
	}

	length := len(g.Image)
	done := make(chan *Result)
	images := make([]*image.Paletted, length)
	processed := 0

	for i := range g.Image {
		go func(paletted *image.Paletted, width int, height int, position int, trans Transformation, options *Options) {
			img := e.Scale(paletted, width, height, options.Upscale, trans)

			bounds := img.Bounds()

			done <- &Result{
				Image:    img,
				Position: position,
				Paletted: image.NewPaletted(image.Rect(0, 0, bounds.Max.X, bounds.Max.Y), paletted.Palette),
			}
		}(g.Image[i], width, height, i, trans, options)
	}

	for {
		select {
		case result := <-done:
			bounds := result.Image.Bounds()

			draw.Draw(result.Paletted, bounds, result.Image, bounds.Min, draw.Src)

			images[result.Position] = result.Paletted

			processed++
		case <-time.After(time.Second * 5):
			break
		}

		if processed == length {
			break
		}
	}

	close(done)

	g.Image = images

	buf := &bytes.Buffer{}

	err = gif.EncodeAll(buf, g)

	if err != nil {
		return nil, err
	}

	return buf.Bytes(), nil
}

func (e *GoImageEngine) Transform(img *imagefile.ImageFile, operation *Operation, qs map[string]string) (*imagefile.ImageFile, error) {
	params := map[string]string{
		"upscale": "1",
		"h":       "0",
		"w":       "0",
		"deg":     "90",
	}

	err := mergo.Merge(&qs, params)

	if err != nil {
		return nil, err
	}

	var quality int
	var format string

	q, ok := qs["q"]

	if ok {
		quality, err := strconv.Atoi(q)

		if err != nil {
			return nil, err
		}

		if quality > 100 {
			return nil, fmt.Errorf("Quality should be <= 100")
		}
	} else {
		quality = e.DefaultQuality
	}

	format, ok = qs["fmt"]
	filepath := img.Filepath

	if ok {
		if _, ok := ContentTypes[format]; !ok {
			return nil, fmt.Errorf("Unknown format %s", format)
		}

	}

	if format == "" && e.Format != "" {
		format = e.Format
	}

	if format == "" {
		format = img.Format()
	}

	if format == "" {
		format = e.DefaultFormat
	}

	if format != img.Format() {
		index := len(filepath) - len(img.Format())

		filepath = filepath[:index] + format
	}

	file := &imagefile.ImageFile{
		Source:   img.Source,
		Key:      img.Key,
		Headers:  img.Headers,
		Filepath: filepath,
	}

	options := &Options{
		Quality: quality,
		Format:  Formats[format],
	}

	switch operation {
	case Flip:
		pos, ok := qs["pos"]

		if !ok {
			return nil, fmt.Errorf("Parameter \"pos\" not found in query string")
		}

		content, err := e.Flip(img, pos, options)

		if err != nil {
			return nil, err
		}

		file.Processed = content

		return file, err
	case Rotate:
		deg, err := strconv.Atoi(qs["deg"])

		if err != nil {
			return nil, err
		}

		content, err := e.Rotate(img, deg, options)

		if err != nil {
//.........这里部分代码省略.........