359 lines
9.0 KiB
Go
359 lines
9.0 KiB
Go
package service
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import (
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"crypto/rand"
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"encoding/hex"
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"errors"
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"fmt"
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"io"
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"os"
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"path/filepath"
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"unicode/utf8"
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"github.com/freefire/jiang13-bbs/model"
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"gorm.io/gorm"
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)
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// 附件默认体积/个数上限（实际限额读 SettingService；此处供校验与测试引用）
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const (
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FileMaxBytes = 20 << 20 // 默认 20 MiB
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MaxPostAttachments = 10
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)
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var (
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ErrAttachmentNotFound = errors.New("附件不存在")
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ErrAttachmentForbidden = errors.New("无权操作此附件")
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ErrTooManyAttachments = errors.New("附件数量超过上限")
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ErrAttachmentExtDenied = errors.New("不支持该附件格式")
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ErrAttachmentTooLarge = errors.New("附件过大")
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ErrAttachmentEmpty = errors.New("文件为空")
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)
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// PostFileService 帖子文件附件（私有目录 + API 下载）
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type PostFileService struct {
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ops *Operations
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db *gorm.DB
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dir string // data/private/files
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setting *SettingService
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}
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func NewPostFileService(db *gorm.DB, privateDir string) *PostFileService {
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return &PostFileService{db: db, dir: filepath.Join(privateDir, "files")}
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}
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// WithSetting 注入站点设置（附件限额/扩展名）
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func (s *PostFileService) WithSetting(setting *SettingService) *PostFileService {
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s.setting = setting
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return s
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}
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func (s *PostFileService) EnsureDir() error {
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return os.MkdirAll(s.dir, 0o755)
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}
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func absPath(dir, stored string) string {
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return filepath.Join(dir, stored)
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}
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func (s *PostFileService) maxBytes() int64 {
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if s.setting == nil {
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return FileMaxBytes
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}
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n, err := s.setting.AttachmentMaxBytes()
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if err != nil || n < 1 {
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return FileMaxBytes
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}
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return n
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}
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func (s *PostFileService) maxCount() int {
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if s.setting == nil {
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return MaxPostAttachments
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}
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n, err := s.setting.AttachmentMaxCount()
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if err != nil || n < 1 {
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return MaxPostAttachments
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}
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return n
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}
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func (s *PostFileService) tooLargeErr() error {
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mb := int(s.maxBytes() >> 20)
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if mb < 1 {
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mb = 1
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}
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return fmt.Errorf("%w：不能超过 %dMB", ErrAttachmentTooLarge, mb)
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}
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// SaveDraftFile 流式落盘附件（先挂 post_id=0，发帖时绑定）。整文件不进内存。
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func (s *PostFileService) SaveDraftFile(userID uint, originalName string, src io.Reader, pricePoints int) (*model.PostAttachment, error) {
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if src == nil {
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return nil, ErrAttachmentEmpty
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}
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if pricePoints < 0 {
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pricePoints = 0
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}
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if pricePoints > 100000 {
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return nil, errors.New("积分定价过高")
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}
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name := sanitizeFilename(originalName)
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if name == "" {
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name = "file"
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}
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ext := ExtOfFilename(name)
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if utf8.RuneCountInString(ext) > 16 {
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ext = ""
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}
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if s.setting != nil {
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ok, err := s.setting.AttachmentExtAllowed(ext)
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if err != nil {
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return nil, err
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}
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if !ok {
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return nil, ErrAttachmentExtDenied
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}
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}
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maxC := s.maxCount()
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var orphan int64
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if err := s.db.Model(&model.PostAttachment{}).
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Where("user_id = ? AND post_id = 0", userID).Count(&orphan).Error; err != nil {
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return nil, err
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}
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if orphan >= int64(maxC) {
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return nil, ErrTooManyAttachments
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}
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maxB := s.maxBytes()
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raw := make([]byte, 16)
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if _, err := rand.Read(raw); err != nil {
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return nil, err
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}
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stored := hex.EncodeToString(raw) + ext
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full := absPath(s.dir, stored)
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tmp := full + ".partial"
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if s.ops != nil {
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release, e := s.ops.BeginTemporary(tmp)
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if e != nil {
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return nil, e
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}
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defer release()
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}
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f, err := os.OpenFile(tmp, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0o600)
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if err != nil {
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return nil, err
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}
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// LimitReader 多读 1 字节以区分「刚好上限」与「超限」
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written, copyErr := io.Copy(f, io.LimitReader(src, maxB+1))
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_ = f.Close()
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if copyErr != nil {
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_ = os.Remove(tmp)
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return nil, copyErr
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}
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if written == 0 {
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_ = os.Remove(tmp)
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return nil, ErrAttachmentEmpty
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}
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if written > maxB {
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_ = os.Remove(tmp)
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return nil, s.tooLargeErr()
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}
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mimeType := ResolveAttachmentMIMEFile(ext, tmp)
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if err := os.Rename(tmp, full); err != nil {
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_ = os.Remove(tmp)
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return nil, err
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}
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att := &model.PostAttachment{
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PostID: 0,
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UserID: userID,
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Name: name,
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StoredName: stored,
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MIME: mimeType,
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Size: int(written),
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PricePoints: pricePoints,
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}
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if s.ops != nil {
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id, e := s.ops.StoreFile(full, att.MIME, false)
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if e != nil {
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_ = os.Remove(full)
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return nil, e
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}
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att.ObjectID = id
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if id != "" {
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_ = os.Remove(full)
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}
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}
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if err := s.db.Create(att).Error; err != nil {
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_ = os.Remove(full)
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return nil, err
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}
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return att, nil
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}
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// BindToPost 将草稿附件绑定到帖子（仅本人、未绑定）
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func (s *PostFileService) BindToPost(userID, postID uint, ids []uint) error {
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if len(ids) == 0 {
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return nil
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}
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maxC := s.maxCount()
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if len(ids) > maxC {
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return ErrTooManyAttachments
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}
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return s.db.Transaction(func(tx *gorm.DB) error {
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var atts []model.PostAttachment
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if err := tx.Where("id IN ? AND user_id = ? AND post_id = 0", ids, userID).Find(&atts).Error; err != nil {
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return err
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}
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if len(atts) != len(ids) {
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return errors.New("部分附件无效或无权使用")
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}
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return tx.Model(&model.PostAttachment{}).
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Where("id IN ? AND user_id = ? AND post_id = 0", ids, userID).
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Update("post_id", postID).Error
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})
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}
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// ReplacePostAttachments 编辑时重绑附件列表（ids 为最终列表；可含已绑定本帖的）
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func (s *PostFileService) ReplacePostAttachments(userID, postID uint, ids []uint) error {
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maxC := s.maxCount()
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if len(ids) > maxC {
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return ErrTooManyAttachments
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}
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return s.db.Transaction(func(tx *gorm.DB) error {
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var keep []model.PostAttachment
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if len(ids) > 0 {
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if err := tx.Where(
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"id IN ? AND user_id = ? AND (post_id = 0 OR post_id = ?)",
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ids, userID, postID,
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).Find(&keep).Error; err != nil {
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return err
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}
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if len(keep) != len(ids) {
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return errors.New("部分附件无效或无权使用")
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}
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}
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if err := tx.Model(&model.PostAttachment{}).
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Where("post_id = ? AND user_id = ?", postID, userID).
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Update("post_id", 0).Error; err != nil {
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return err
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}
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if len(ids) == 0 {
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return nil
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}
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return tx.Model(&model.PostAttachment{}).
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Where("id IN ? AND user_id = ?", ids, userID).
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Update("post_id", postID).Error
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})
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}
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// ListByPost 帖子附件列表
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func (s *PostFileService) ListByPost(postID uint) ([]model.PostAttachment, error) {
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var list []model.PostAttachment
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err := s.db.Where("post_id = ?", postID).Order("id ASC").Find(&list).Error
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return list, err
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}
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// UpdatePrice 更新附件积分定价（作者）
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func (s *PostFileService) UpdatePrice(userID, attID uint, price int) error {
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if price < 0 {
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price = 0
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}
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res := s.db.Model(&model.PostAttachment{}).
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Where("id = ? AND user_id = ?", attID, userID).
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Update("price_points", price)
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if res.Error != nil {
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return res.Error
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}
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if res.RowsAffected == 0 {
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return ErrAttachmentNotFound
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}
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return nil
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}
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// DeleteOwn 删除本人未绑定或本帖附件
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func (s *PostFileService) DeleteOwn(userID, attID uint) error {
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var att model.PostAttachment
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if err := s.db.First(&att, attID).Error; err != nil {
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return ErrAttachmentNotFound
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}
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if att.UserID != userID {
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return ErrAttachmentForbidden
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}
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path := absPath(s.dir, att.StoredName)
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if err := s.db.Delete(&att).Error; err != nil {
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return err
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}
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if s.ops != nil && att.ObjectID != "" {
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return s.ops.RemoveObject(att.ObjectID)
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}
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_ = os.Remove(path)
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return nil
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}
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// Get 按 ID 取附件
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func (s *PostFileService) Get(attID uint) (*model.PostAttachment, error) {
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var att model.PostAttachment
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if err := s.db.First(&att, attID).Error; err != nil {
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return nil, ErrAttachmentNotFound
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}
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return &att, nil
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}
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func (s *PostFileService) FilePath(att *model.PostAttachment) string {
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return absPath(s.dir, att.StoredName)
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}
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func (s *PostFileService) IncDownload(attID uint) {
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s.db.Model(&model.PostAttachment{}).Where("id = ?", attID).
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UpdateColumn("download_count", gorm.Expr("download_count + 1"))
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}
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// EnsureAttachmentUnlocked 免费或已购/作者；积分附件扣费一次
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func (s *PostFileService) EnsureAttachmentUnlocked(userID uint, att *model.PostAttachment) error {
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if att.PricePoints <= 0 {
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return nil
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}
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if att.UserID == userID {
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return nil
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}
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var n int64
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if err := s.db.Model(&model.PostAttachmentUnlock{}).
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Where("attachment_id = ? AND user_id = ?", att.ID, userID).
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Count(&n).Error; err != nil {
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return err
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}
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if n > 0 {
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return nil
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}
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return s.db.Transaction(func(tx *gorm.DB) error {
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var again int64
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if err := tx.Model(&model.PostAttachmentUnlock{}).
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Where("attachment_id = ? AND user_id = ?", att.ID, userID).
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Count(&again).Error; err != nil {
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return err
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}
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if again > 0 {
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return nil
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}
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if _, err := DebitTx(tx, userID, att.PricePoints, model.PointReasonDownloadFile, "attachment", att.ID, "下载附件："+att.Name); err != nil {
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return err
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}
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if att.UserID > 0 && att.UserID != userID {
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if _, err := CreditTx(tx, att.UserID, att.PricePoints, model.PointReasonDownloadFile, "attachment_earn", att.ID, "附件收益："+att.Name); err != nil {
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return err
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}
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}
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return tx.Create(&model.PostAttachmentUnlock{
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AttachmentID: att.ID,
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UserID: userID,
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Points: att.PricePoints,
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}).Error
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})
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}
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func (s *PostFileService) WithOperations(o *Operations) { s.ops = o }
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