feat(serverHandler): add download action

Author: marjune163

doc/en-US/api.md

@@ -36,6 +36,17 @@ Example:
 curl http://localhost/ghfs/?json
 ```
 
+# Download a file
+Notify user agent download a file rather than display its content.
+```
+GET <path/to/file>?download
+```
+
+Example:
+```sh
+curl http://localhost/ghfs/file?download
+```
+
 # Get contents of specified path as archive file
 Only work when "archive" is enabled.
 ```

doc/zh-CN/api.md

@@ -36,6 +36,17 @@ GET <path>?json[&sort=key]
 curl http://localhost/ghfs/?json
 ```
 
+# 下载文件
+通知用户代理下载文件而不是显示其内容。
+```
+GET <path/to/file>?download
+```
+
+举例：
+```sh
+curl http://localhost/ghfs/file?download
+```
+
 # 以打包文件形式获取指定路径下的内容
 仅在“archive”选项启用时有效。
 ```

src/serverHandler/content.go

@@ -27,6 +27,11 @@ func getContentType(item os.FileInfo, file *os.File) (string, error) {
 }
 
 func (h *handler) content(w http.ResponseWriter, r *http.Request, data *responseData) {
+	header := w.Header()
+	if data.IsDownload {
+		header.Set("Content-Disposition", "attachment; filename*=UTF-8''"+data.ItemName)
+	}
+
 	item := data.Item
 	file := data.File
 
@@ -37,7 +42,6 @@ func (h *handler) content(w http.ResponseWriter, r *http.Request, data *response
 
 	ctype, err := getContentType(item, file)
 	if err == nil {
-		header := w.Header()
 		header.Set("Content-Type", ctype)
 		header.Set("Content-Length", strconv.FormatInt(item.Size(), 10))
 		header.Set("Date", time.Now().UTC().Format(http.TimeFormat))

src/serverHandler/responseData.go

@@ -53,11 +53,12 @@ type responseData struct {
 	CanCors      bool
 	NeedAuth     bool
 
-	IsUpload bool
-	IsMkdir  bool
-	IsDelete bool
-	IsMutate bool
-	WantJson bool
+	IsDownload bool
+	IsUpload   bool
+	IsMkdir    bool
+	IsDelete   bool
+	IsMutate   bool
+	WantJson   bool
 }
 
 func isSlash(c rune) bool {
@@ -353,11 +354,14 @@ func (h *handler) getResponseData(r *http.Request) *responseData {
 	canCors := h.getCanCors(rawReqPath, reqFsPath)
 	needAuth := h.getNeedAuth(rawReqPath, reqFsPath)
 
+	isDownload := false
 	isUpload := false
 	isMkdir := false
 	isDelete := false
 	isMutate := false
 	switch {
+	case strings.HasPrefix(rawQuery, "download"):
+		isDownload = true
 	case strings.HasPrefix(rawQuery, "upload") && r.Method == http.MethodPost:
 		isUpload = true
 		isMutate = true
@@ -399,10 +403,11 @@ func (h *handler) getResponseData(r *http.Request) *responseData {
 		CanCors:      canCors,
 		NeedAuth:     needAuth,
 
-		IsUpload: isUpload,
-		IsMkdir:  isMkdir,
-		IsDelete: isDelete,
-		IsMutate: isMutate,
-		WantJson: wantJson,
+		IsDownload: isDownload,
+		IsUpload:   isUpload,
+		IsMkdir:    isMkdir,
+		IsDelete:   isDelete,
+		IsMutate:   isMutate,
+		WantJson:   wantJson,
 	}
 }