Function DecodeUrlImageData

service/image.go:113–153

(imageUrl string)

}

func DecodeUrlImageData(imageUrl string) (image.Config, string, error) {
	response, err := DoDownloadRequest(imageUrl)
	if err != nil {
		common.SysLog(fmt.Sprintf("fail to get image from url: %s", err.Error()))
		return image.Config{}, "", err
	}
	defer response.Body.Close()

	if response.StatusCode != 200 {
		err = errors.New(fmt.Sprintf("fail to get image from url: %s", response.Status))
		return image.Config{}, "", err
	}

	mimeType := response.Header.Get("Content-Type")

	if mimeType != "application/octet-stream" && !strings.HasPrefix(mimeType, "image/") {
		return image.Config{}, "", fmt.Errorf("invalid content type: %s, required image/*", mimeType)
	}

	var readData []byte
	for _, limit := range []int64{1024 * 8, 1024 * 24, 1024 * 64} {
		common.SysLog(fmt.Sprintf("try to decode image config with limit: %d", limit))

		// 从response.Body读取更多的数据直到达到当前的限制
		additionalData := make([]byte, limit-int64(len(readData)))
		n, _ := io.ReadFull(response.Body, additionalData)
		readData = append(readData, additionalData[:n]...)

		// 使用io.MultiReader组合已经读取的数据和response.Body
		limitReader := io.MultiReader(bytes.NewReader(readData), response.Body)

		var config image.Config
		var format string
		config, format, err = getImageConfig(limitReader)
		if err == nil {
			return config, format, nil
		}
	}

	return image.Config{}, "", err // 返回最后一个错误
}

func getImageConfig(reader io.Reader) (image.Config, string, error) {
	// 读取图片的头部信息来获取图片尺寸