121 lines
3.0 KiB
Go
121 lines
3.0 KiB
Go
package fileStorage
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import (
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"context"
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"encoding/base64"
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"fmt"
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"strings"
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"time"
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"backend/internal/svc"
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"backend/internal/types"
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"github.com/google/uuid"
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"github.com/zeromicro/go-zero/core/logx"
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)
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type UploadImgLogic struct {
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logx.Logger
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ctx context.Context
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svcCtx *svc.ServiceContext
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}
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// 上傳圖片檔案
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func NewUploadImgLogic(ctx context.Context, svcCtx *svc.ServiceContext) *UploadImgLogic {
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return &UploadImgLogic{
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Logger: logx.WithContext(ctx),
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ctx: ctx,
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svcCtx: svcCtx,
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}
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}
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func (l *UploadImgLogic) UploadImg(req *types.UploadImgReq) (resp *types.UploadResp, err error) {
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// 驗證 base64 格式
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content := req.Content
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if strings.HasPrefix(content, "data:image") {
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// 移除 data URL 前綴 (例如: data:image/png;base64,)
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parts := strings.SplitN(content, ",", 2)
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if len(parts) != 2 {
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return nil, fmt.Errorf("invalid base64 image format")
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}
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content = parts[1]
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}
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// 解碼 base64
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imgData, err := base64.StdEncoding.DecodeString(content)
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if err != nil {
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return nil, fmt.Errorf("failed to decode base64: %w", err)
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}
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// 驗證文件大小（10MB 限制）
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const maxImgSize = 10 << 20 // 10MB
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if len(imgData) > maxImgSize {
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return nil, fmt.Errorf("image size exceeds 10MB limit")
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}
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// 驗證圖片格式（檢查 magic bytes）
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mimeType, err := l.detectImageType(imgData)
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if err != nil {
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return nil, fmt.Errorf("invalid image format: %w", err)
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}
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// 生成唯一文件名
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fileExt := l.getExtensionFromMimeType(mimeType)
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fileName := fmt.Sprintf("%s%s", uuid.New().String(), fileExt)
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objectPath := fmt.Sprintf("images/%d/%s", time.Now().Year(), fileName)
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// 上傳到 S3
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fileStorageUC := l.svcCtx.FileStorageUC
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if err := fileStorageUC.UploadFromData(l.ctx, imgData, objectPath, mimeType); err != nil {
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return nil, fmt.Errorf("failed to upload image: %w", err)
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}
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// 獲取公開 URL
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fileUrl := fileStorageUC.GetPublicURL(l.ctx, objectPath)
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return &types.UploadResp{
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FileUrl: fileUrl,
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FileSize: int64(len(imgData)),
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MimeType: mimeType,
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}, nil
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}
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// detectImageType 檢測圖片類型
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func (l *UploadImgLogic) detectImageType(data []byte) (string, error) {
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if len(data) < 4 {
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return "", fmt.Errorf("file too small")
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}
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// 檢查常見圖片格式的 magic bytes
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if len(data) >= 2 && data[0] == 0xFF && data[1] == 0xD8 {
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return "image/jpeg", nil
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}
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if len(data) >= 8 && string(data[0:8]) == "\x89PNG\r\n\x1a\n" {
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return "image/png", nil
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}
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if len(data) >= 6 && (string(data[0:6]) == "GIF87a" || string(data[0:6]) == "GIF89a") {
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return "image/gif", nil
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}
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if len(data) >= 12 && string(data[8:12]) == "WEBP" {
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return "image/webp", nil
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}
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return "", fmt.Errorf("unsupported image format")
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}
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// getExtensionFromMimeType 根據 MIME 類型獲取文件擴展名
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func (l *UploadImgLogic) getExtensionFromMimeType(mimeType string) string {
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switch mimeType {
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case "image/jpeg":
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return ".jpg"
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case "image/png":
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return ".png"
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case "image/gif":
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return ".gif"
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case "image/webp":
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return ".webp"
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default:
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return ".jpg"
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}
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}
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