tss-rocks/backend/internal/middleware/upload.go
CDN 05ddc1f783
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159 lines
3.8 KiB
Go

package middleware
import (
"bytes"
"fmt"
"io"
"net/http"
"path/filepath"
"strings"
"github.com/gin-gonic/gin"
"tss-rocks-be/internal/types"
)
const (
defaultMaxMemory = 32 << 20 // 32 MB
maxHeaderBytes = 512 // 用于MIME类型检测的最大字节数
)
// ValidateUpload 创建文件上传验证中间件
func ValidateUpload(cfg *types.UploadConfig) gin.HandlerFunc {
return func(c *gin.Context) {
// 检查是否是multipart/form-data请求
if !strings.HasPrefix(c.GetHeader("Content-Type"), "multipart/form-data") {
c.JSON(http.StatusBadRequest, gin.H{
"error": "Content-Type must be multipart/form-data",
})
c.Abort()
return
}
// 解析multipart表单
if err := c.Request.ParseMultipartForm(defaultMaxMemory); err != nil {
c.JSON(http.StatusBadRequest, gin.H{
"error": fmt.Sprintf("Failed to parse form: %v", err),
})
c.Abort()
return
}
form := c.Request.MultipartForm
if form == nil || form.File == nil {
c.JSON(http.StatusBadRequest, gin.H{
"error": "No file uploaded",
})
c.Abort()
return
}
// 遍历所有上传的文件
for _, files := range form.File {
for _, file := range files {
// 检查文件大小
if file.Size > int64(cfg.MaxSize)<<20 { // 转换为字节
c.JSON(http.StatusBadRequest, gin.H{
"error": fmt.Sprintf("File %s exceeds maximum size of %d MB", file.Filename, cfg.MaxSize),
})
c.Abort()
return
}
// 检查文件扩展名
ext := strings.ToLower(filepath.Ext(file.Filename))
if !contains(cfg.AllowedExtensions, ext) {
c.JSON(http.StatusBadRequest, gin.H{
"error": fmt.Sprintf("File extension %s is not allowed", ext),
})
c.Abort()
return
}
// 打开文件
src, err := file.Open()
if err != nil {
c.JSON(http.StatusInternalServerError, gin.H{
"error": fmt.Sprintf("Failed to open file: %v", err),
})
c.Abort()
return
}
defer src.Close()
// 读取文件头部用于MIME类型检测
header := make([]byte, maxHeaderBytes)
n, err := src.Read(header)
if err != nil && err != io.EOF {
c.JSON(http.StatusInternalServerError, gin.H{
"error": fmt.Sprintf("Failed to read file: %v", err),
})
c.Abort()
return
}
header = header[:n]
// 检测MIME类型
contentType := http.DetectContentType(header)
if !contains(cfg.AllowedTypes, contentType) {
c.JSON(http.StatusBadRequest, gin.H{
"error": fmt.Sprintf("File type %s is not allowed", contentType),
})
c.Abort()
return
}
// 将文件指针重置到开始位置
_, err = src.Seek(0, 0)
if err != nil {
c.JSON(http.StatusInternalServerError, gin.H{
"error": fmt.Sprintf("Failed to read file: %v", err),
})
c.Abort()
return
}
// 将文件内容读入缓冲区
buf := &bytes.Buffer{}
_, err = io.Copy(buf, src)
if err != nil {
c.JSON(http.StatusInternalServerError, gin.H{
"error": fmt.Sprintf("Failed to read file: %v", err),
})
c.Abort()
return
}
// 将验证过的文件内容和类型保存到上下文中
c.Set("validated_file_"+file.Filename, buf)
c.Set("validated_content_type_"+file.Filename, contentType)
}
}
c.Next()
}
}
// contains 检查切片中是否包含指定的字符串
func contains(slice []string, str string) bool {
for _, s := range slice {
if s == str {
return true
}
}
return false
}
// GetValidatedFile 从上下文中获取验证过的文件内容
func GetValidatedFile(c *gin.Context, filename string) (*bytes.Buffer, string, bool) {
file, exists := c.Get("validated_file_" + filename)
if !exists {
return nil, "", false
}
contentType, exists := c.Get("validated_content_type_" + filename)
if !exists {
return nil, "", false
}
return file.(*bytes.Buffer), contentType.(string), true
}