feat: use cobra to provide subcommands, move sources to lib (#506)

- Use cobra in order to provide subcommands `serve` and `db`.
  - Subdir `cmd` is removed.
  - Subdir `cli` is created, which is a standard cobra structure.
- Sources related to the core are moved to subdir `lib`.
- #497 and #504 are merged.
- Deprecated flags are added. See https://github.com/filebrowser/filebrowser/pull/497#discussion_r209428120.
- [`viper.BindPFlags`](https://godoc.org/github.com/spf13/viper#BindPFlags) is used in order to reduce the verbosity in `serve.go`.


Former-commit-id: 4b37ad82e91e01f7718cd389469814674bdf7032 [formerly c84d7fcf9c362b2aa1f9e5b57196152f53835e61] [formerly 2fef43c0382f3cc7d13e0297ccb467e38fac6982 [formerly 69a3f853bd2821d2c52a435277aaac68a468d39b]]
Former-commit-id: 2f7dc1b8ee6735382cedae2053f40c546c21de45 [formerly b438417178b47ad5f7caf9cb728f4a5011a09f5e]
Former-commit-id: 07bc58ab2e1ab10c30be8d0a5e760288bfc4d4dc

lib/http/share.go

@@ -0,0 +1,127 @@
+package http
+
+import (
+	"encoding/base64"
+	"net/http"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	fb "github.com/filebrowser/filebrowser/lib"
+)
+
+func shareHandler(c *fb.Context, w http.ResponseWriter, r *http.Request) (int, error) {
+	r.URL.Path = sanitizeURL(r.URL.Path)
+
+	switch r.Method {
+	case http.MethodGet:
+		return shareGetHandler(c, w, r)
+	case http.MethodDelete:
+		return shareDeleteHandler(c, w, r)
+	case http.MethodPost:
+		return sharePostHandler(c, w, r)
+	}
+
+	return http.StatusNotImplemented, nil
+}
+
+func shareGetHandler(c *fb.Context, w http.ResponseWriter, r *http.Request) (int, error) {
+	path := filepath.Join(c.User.Scope, r.URL.Path)
+	s, err := c.Store.Share.GetByPath(path)
+	if err == fb.ErrNotExist {
+		return http.StatusNotFound, nil
+	}
+
+	if err != nil {
+		return http.StatusInternalServerError, err
+	}
+
+	for i, link := range s {
+		if link.Expires && link.ExpireDate.Before(time.Now()) {
+			c.Store.Share.Delete(link.Hash)
+			s = append(s[:i], s[i+1:]...)
+		}
+	}
+
+	if len(s) == 0 {
+		return http.StatusNotFound, nil
+	}
+
+	return renderJSON(w, s)
+}
+
+func sharePostHandler(c *fb.Context, w http.ResponseWriter, r *http.Request) (int, error) {
+	path := filepath.Join(c.User.Scope, r.URL.Path)
+
+	var s *fb.ShareLink
+	expire := r.URL.Query().Get("expires")
+	unit := r.URL.Query().Get("unit")
+
+	if expire == "" {
+		var err error
+		s, err = c.Store.Share.GetPermanent(path)
+		if err == nil {
+			w.Write([]byte(c.RootURL() + "/share/" + s.Hash))
+			return 0, nil
+		}
+	}
+
+	bytes, err := fb.GenerateRandomBytes(6)
+	if err != nil {
+		return http.StatusInternalServerError, err
+	}
+
+	str := base64.URLEncoding.EncodeToString(bytes)
+
+	s = &fb.ShareLink{
+		Path:    path,
+		Hash:    str,
+		Expires: expire != "",
+	}
+
+	if expire != "" {
+		num, err := strconv.Atoi(expire)
+		if err != nil {
+			return http.StatusInternalServerError, err
+		}
+
+		var add time.Duration
+		switch unit {
+		case "seconds":
+			add = time.Second * time.Duration(num)
+		case "minutes":
+			add = time.Minute * time.Duration(num)
+		case "days":
+			add = time.Hour * 24 * time.Duration(num)
+		default:
+			add = time.Hour * time.Duration(num)
+		}
+
+		s.ExpireDate = time.Now().Add(add)
+	}
+
+	if err := c.Store.Share.Save(s); err != nil {
+		return http.StatusInternalServerError, err
+	}
+
+	return renderJSON(w, s)
+}
+
+func shareDeleteHandler(c *fb.Context, w http.ResponseWriter, r *http.Request) (int, error) {
+	s, err := c.Store.Share.Get(strings.TrimPrefix(r.URL.Path, "/"))
+	if err == fb.ErrNotExist {
+		return http.StatusNotFound, nil
+	}
+
+	if err != nil {
+		return http.StatusInternalServerError, err
+	}
+
+	err = c.Store.Share.Delete(s.Hash)
+	if err != nil {
+		return http.StatusInternalServerError, err
+	}
+
+	return http.StatusOK, nil
+}