fix(webdav): wrong MIMEType (close #1007)

server/webdav/file.go

@@ -14,6 +14,7 @@ import (
 	"github.com/Xhofe/alist/server/common"
 	"github.com/Xhofe/alist/utils"
 	log "github.com/sirupsen/logrus"
+	"mime"
 	"net"
 	"net/http"
 	"path"
@@ -197,8 +198,15 @@ func (fs *FileSystem) Upload(ctx context.Context, r *http.Request, rawPath strin
 	} else {
 		delete(upFileMap, rawPath)
 	}
+	mimeType := r.Header.Get("Content-Type")
+	if mimeType == "" || strings.ToLower(mimeType) == "application/octet-stream" {
+		mimeTypeTmp := mime.TypeByExtension(path.Ext(fileName))
+		if mimeTypeTmp != "" {
+			mimeType = mimeTypeTmp
+		}
+	}
 	fileData := model.FileStream{
-		MIMEType:   r.Header.Get("Content-Type"),
+		MIMEType:   mimeType,
 		File:       r.Body,
 		Size:       fileSize,
 		Name:       fileName,