feat: gemini image support edit

relay/common/relay_utils.go

@@ -1,7 +1,10 @@
 package common
 
 import (
+	"encoding/base64"
+	"errors"
 	"fmt"
+	"io"
 	"net/http"
 	"strconv"
 	"strings"
@@ -226,3 +229,54 @@ func ValidateBasicTaskRequest(c *gin.Context, info *RelayInfo, action string) *d
 	storeTaskRequest(c, info, action, req)
 	return nil
 }
+func GetImagesBase64sFromForm(c *gin.Context) ([]*Base64Data, error) {
+	return GetBase64sFromForm(c, "image")
+}
+func GetImageBase64sFromForm(c *gin.Context) (*Base64Data, error) {
+	base64s, err := GetImagesBase64sFromForm(c)
+	if err != nil {
+		return nil, err
+	}
+	return base64s[0], nil
+}
+
+type Base64Data struct {
+	MimeType string
+	Data     string
+}
+
+func (m Base64Data) String() string {
+	return fmt.Sprintf("data:%s;base64,%s", m.MimeType, m.Data)
+}
+func GetBase64sFromForm(c *gin.Context, fieldName string) ([]*Base64Data, error) {
+	mf := c.Request.MultipartForm
+	if mf == nil {
+		if _, err := c.MultipartForm(); err != nil {
+			return nil, fmt.Errorf("failed to parse image edit form request: %w", err)
+		}
+		mf = c.Request.MultipartForm
+	}
+	imageFiles, exists := mf.File[fieldName]
+	if !exists || len(imageFiles) == 0 {
+		return nil, errors.New("field " + fieldName + "\" is not found or empty")
+	}
+	var imageBase64s []*Base64Data
+	for _, file := range imageFiles {
+		image, err := file.Open()
+		if err != nil {
+			return nil, errors.New("failed to open image file")
+		}
+		imageData, err := io.ReadAll(image)
+		if err != nil {
+			return nil, errors.New("failed to read image file")
+		}
+		mimeType := http.DetectContentType(imageData)
+		base64Data := base64.StdEncoding.EncodeToString(imageData)
+		imageBase64s = append(imageBase64s, &Base64Data{
+			MimeType: mimeType,
+			Data:     base64Data,
+		})
+		image.Close()
+	}
+	return imageBase64s, nil
+}