Method ServeFile

pkg/server/download.go:300–378

(w http.ResponseWriter, r *http.Request, file blob.Ref)

}

func (dh *DownloadHandler) ServeFile(w http.ResponseWriter, r *http.Request, file blob.Ref) {
	ctx := r.Context()
	if r.Method != "GET" && r.Method != "HEAD" {
		http.Error(w, "Invalid download method", http.StatusBadRequest)
		return
	}

	if r.Header.Get("If-Modified-Since") != "" {
		// Immutable, so any copy's a good copy.
		w.WriteHeader(http.StatusNotModified)
		return
	}

	dh.r = r
	fi, packed, err := dh.fileInfo(ctx, file)
	if err != nil {
		http.Error(w, "Can't serve file: "+err.Error(), http.StatusInternalServerError)
		return
	}
	if !fi.mode.IsRegular() {
		http.Error(w, "Not a regular file", http.StatusBadRequest)
		return
	}
	defer fi.close()

	h := w.Header()
	h.Set("Content-Length", fmt.Sprint(fi.size))
	h.Set("Expires", time.Now().UTC().Add(oneYear).Format(http.TimeFormat))
	if packed {
		h.Set("X-Camlistore-Packed", "1")
	}

	fileName := func(ext string) string {
		if fi.name != "" {
			return fi.name
		}
		return "file-" + file.String() + ext
	}

	if r.FormValue("inline") == "1" || dh.forceInline {
		// TODO(mpl): investigate why at least text files have an incorrect MIME.
		if fi.mime == "application/octet-stream" {
			// Since e.g. plain text files are seen as "application/octet-stream", we force
			// check for that, so we can have the browser display them as text if they are
			// indeed actually text.
			text, err := isText(fi.rs)
			if err != nil {
				// TODO: https://perkeep.org/issues/1060
				httputil.ServeError(w, r, fmt.Errorf("cannot verify MIME type of file: %v", err))
				return
			}
			if text {
				fi.mime = "text/plain"
			}
		}
		h.Set("Content-Disposition", "inline")
	} else {
		w.Header().Set("Content-Disposition", "attachment; filename="+fileName(".dat"))