support base64 image

common/image.go

@@ -0,0 +1,64 @@
+package common
+
+import (
+	"bytes"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"github.com/chai2010/webp"
+	"image"
+	"io"
+	"net/http"
+	"strings"
+)
+
+func DecodeBase64ImageData(base64String string) (image.Config, error) {
+	// 去除base64数据的URL前缀（如果有）
+	if idx := strings.Index(base64String, ","); idx != -1 {
+		base64String = base64String[idx+1:]
+	}
+
+	// 将base64字符串解码为字节切片
+	decodedData, err := base64.StdEncoding.DecodeString(base64String)
+	if err != nil {
+		fmt.Println("Error: Failed to decode base64 string")
+		return image.Config{}, err
+	}
+
+	// 创建一个bytes.Buffer用于存储解码后的数据
+	reader := bytes.NewReader(decodedData)
+	config, err := getImageConfig(reader)
+	return config, err
+}
+
+func DecodeUrlImageData(imageUrl string) (image.Config, error) {
+	response, err := http.Get(imageUrl)
+	if err != nil {
+		SysLog(fmt.Sprintf("fail to get image from url: %s", err.Error()))
+		return image.Config{}, err
+	}
+
+	// 限制读取的字节数，防止下载整个图片
+	limitReader := io.LimitReader(response.Body, 8192)
+	config, err := getImageConfig(limitReader)
+	response.Body.Close()
+	return config, err
+}
+
+func getImageConfig(reader io.Reader) (image.Config, error) {
+	// 读取图片的头部信息来获取图片尺寸
+	config, _, err := image.DecodeConfig(reader)
+	if err != nil {
+		err = errors.New(fmt.Sprintf("fail to decode image config(gif, jpg, png): %s", err.Error()))
+		SysLog(err.Error())
+		config, err = webp.DecodeConfig(reader)
+		if err != nil {
+			err = errors.New(fmt.Sprintf("fail to decode image config(webp): %s", err.Error()))
+			SysLog(err.Error())
+		}
+	}
+	if err != nil {
+		return image.Config{}, err
+	}
+	return config, nil
+}