实现文件上传

web/services/article.go

@@ -2,12 +2,22 @@ package services
 
 import (
 	"errors"
+	"fmt"
+	"io"
+	"mime/multipart"
+	"net/http"
+	"os"
+	"path"
+	"path/filepath"
+	"platform/pkg/env"
 	"platform/pkg/u"
 	"platform/web/core"
 	m "platform/web/models"
 	q "platform/web/queries"
+	"strings"
 	"time"
 
+	"github.com/google/uuid"
 	"gorm.io/gen/field"
 	"gorm.io/gorm"
 )
@@ -16,6 +26,128 @@ var Article = &articleService{}
 
 type articleService struct{}
 
+var articleUploadMimeExt = map[string]string{
+	"image/gif":  ".gif",
+	"image/jpeg": ".jpg",
+	"image/png":  ".png",
+	"image/webp": ".webp",
+}
+
+type ArticleUploadResult struct {
+	URL          string `json:"url"`
+	Path         string `json:"path"`
+	OriginalName string `json:"original_name"`
+	Size         int64  `json:"size"`
+	MimeType     string `json:"mime_type"`
+}
+
+func (s *articleService) UploadImage(fileHeader *multipart.FileHeader, baseURL string) (*ArticleUploadResult, error) {
+	if fileHeader == nil {
+		return nil, core.NewBizErr("缺少上传文件")
+	}
+	if fileHeader.Size > int64(env.ArticleUploadMaxBytes) {
+		return nil, core.NewBizErr(fmt.Sprintf("图片大小不能超过 %s", formatUploadSizeLimit(env.ArticleUploadMaxBytes)))
+	}
+
+	mimeType, ext, err := detectArticleImage(fileHeader)
+	if err != nil {
+		return nil, err
+	}
+
+	now := time.Now()
+	year := now.Format("2006")
+	month := now.Format("01")
+	fileName := uuid.NewString() + ext
+	relativePath := path.Join("/uploads", "article", year, month, fileName)
+	targetDir := filepath.Join(env.UploadDir, "article", year, month)
+	finalPath := filepath.Join(targetDir, fileName)
+
+	if err := os.MkdirAll(targetDir, 0o755); err != nil {
+		return nil, core.NewServErr("创建上传目录失败", err)
+	}
+
+	src, err := fileHeader.Open()
+	if err != nil {
+		return nil, core.NewServErr("打开上传文件失败", err)
+	}
+	defer src.Close()
+
+	tmp, err := os.CreateTemp(targetDir, "upload-*"+ext)
+	if err != nil {
+		return nil, core.NewServErr("创建临时文件失败", err)
+	}
+
+	tmpPath := tmp.Name()
+	finished := false
+	defer func() {
+		if !finished {
+			_ = tmp.Close()
+			_ = os.Remove(tmpPath)
+		}
+	}()
+
+	limitedReader := &io.LimitedReader{R: src, N: int64(env.ArticleUploadMaxBytes) + 1}
+	written, err := io.Copy(tmp, limitedReader)
+	if err != nil {
+		return nil, core.NewServErr("保存上传文件失败", err)
+	}
+	if written > int64(env.ArticleUploadMaxBytes) {
+		return nil, core.NewBizErr(fmt.Sprintf("图片大小不能超过 %s", formatUploadSizeLimit(env.ArticleUploadMaxBytes)))
+	}
+	if err := tmp.Close(); err != nil {
+		return nil, core.NewServErr("关闭临时文件失败", err)
+	}
+	if err := os.Rename(tmpPath, finalPath); err != nil {
+		return nil, core.NewServErr("保存上传文件失败", err)
+	}
+	finished = true
+
+	cleanBaseURL := strings.TrimRight(baseURL, "/")
+	url := relativePath
+	if cleanBaseURL != "" {
+		url = cleanBaseURL + relativePath
+	}
+
+	return &ArticleUploadResult{
+		URL:          url,
+		Path:         relativePath,
+		OriginalName: filepath.Base(fileHeader.Filename),
+		Size:         written,
+		MimeType:     mimeType,
+	}, nil
+}
+
+func detectArticleImage(fileHeader *multipart.FileHeader) (string, string, error) {
+	file, err := fileHeader.Open()
+	if err != nil {
+		return "", "", core.NewServErr("打开上传文件失败", err)
+	}
+	defer file.Close()
+
+	buf := make([]byte, 512)
+	n, err := io.ReadFull(file, buf)
+	if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
+		return "", "", core.NewServErr("读取上传文件失败", err)
+	}
+
+	mimeType := http.DetectContentType(buf[:n])
+	ext, ok := articleUploadMimeExt[mimeType]
+	if !ok {
+		return "", "", core.NewBizErr("仅支持 JPG、PNG、WEBP、GIF 图片")
+	}
+	return mimeType, ext, nil
+}
+
+func formatUploadSizeLimit(bytes int) string {
+	if bytes%(1024*1024) == 0 {
+		return fmt.Sprintf("%d MB", bytes/(1024*1024))
+	}
+	if bytes%1024 == 0 {
+		return fmt.Sprintf("%d KB", bytes/1024)
+	}
+	return fmt.Sprintf("%d bytes", bytes)
+}
+
 func (s *articleService) Page(req *PageArticleReq) (result []*m.Article, count int64, err error) {
 	do := q.Article.Where()
 	if req.Keyword != nil && *req.Keyword != "" {