feat: add image counter for gpt-4 vision (#795)

common/image/image.go

@@ -0,0 +1,47 @@
+package image
+
+import (
+	"image"
+	_ "image/gif"
+	_ "image/jpeg"
+	_ "image/png"
+	"net/http"
+	"regexp"
+	"strings"
+
+	_ "golang.org/x/image/webp"
+)
+
+func GetImageSizeFromUrl(url string) (width int, height int, err error) {
+	resp, err := http.Get(url)
+	if err != nil {
+		return
+	}
+	defer resp.Body.Close()
+	img, _, err := image.DecodeConfig(resp.Body)
+	if err != nil {
+		return
+	}
+	return img.Width, img.Height, nil
+}
+
+var (
+	reg = regexp.MustCompile(`data:image/([^;]+);base64,`)
+)
+
+func GetImageSizeFromBase64(encoded string) (width int, height int, err error) {
+	encoded = strings.TrimPrefix(encoded, "data:image/png;base64,")
+	base64 := strings.NewReader(reg.ReplaceAllString(encoded, ""))
+	img, _, err := image.DecodeConfig(base64)
+	if err != nil {
+		return
+	}
+	return img.Width, img.Height, nil
+}
+
+func GetImageSize(image string) (width int, height int, err error) {
+	if strings.HasPrefix(image, "data:image/") {
+		return GetImageSizeFromBase64(image)
+	}
+	return GetImageSizeFromUrl(image)
+}