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 69a3f853bd]]
Former-commit-id: 2f7dc1b8ee6735382cedae2053f40c546c21de45 [formerly b438417178b47ad5f7caf9cb728f4a5011a09f5e]
Former-commit-id: 07bc58ab2e1ab10c30be8d0a5e760288bfc4d4dc

http/settings.go

@@ -1,146 +0,0 @@
-package http
-
-import (
-	"bytes"
-	"encoding/json"
-	"net/http"
-	"reflect"
-
-	fb "github.com/filebrowser/filebrowser"
-	"github.com/mitchellh/mapstructure"
-)
-
-type modifySettingsRequest struct {
-	modifyRequest
-	Data struct {
-		CSS       string                 `json:"css"`
-		Commands  map[string][]string    `json:"commands"`
-		StaticGen map[string]interface{} `json:"staticGen"`
-	} `json:"data"`
-}
-
-type option struct {
-	Variable string      `json:"variable"`
-	Name     string      `json:"name"`
-	Value    interface{} `json:"value"`
-}
-
-func parsePutSettingsRequest(r *http.Request) (*modifySettingsRequest, error) {
-	// Checks if the request body is empty.
-	if r.Body == nil {
-		return nil, fb.ErrEmptyRequest
-	}
-
-	// Parses the request body and checks if it's well formed.
-	mod := &modifySettingsRequest{}
-	err := json.NewDecoder(r.Body).Decode(mod)
-	if err != nil {
-		return nil, err
-	}
-
-	// Checks if the request type is right.
-	if mod.What != "settings" {
-		return nil, fb.ErrWrongDataType
-	}
-
-	return mod, nil
-}
-
-func settingsHandler(c *fb.Context, w http.ResponseWriter, r *http.Request) (int, error) {
-	if r.URL.Path != "" && r.URL.Path != "/" {
-		return http.StatusNotFound, nil
-	}
-
-	switch r.Method {
-	case http.MethodGet:
-		return settingsGetHandler(c, w, r)
-	case http.MethodPut:
-		return settingsPutHandler(c, w, r)
-	}
-
-	return http.StatusMethodNotAllowed, nil
-}
-
-type settingsGetRequest struct {
-	CSS       string              `json:"css"`
-	Commands  map[string][]string `json:"commands"`
-	StaticGen []option            `json:"staticGen"`
-}
-
-func settingsGetHandler(c *fb.Context, w http.ResponseWriter, r *http.Request) (int, error) {
-	if !c.User.Admin {
-		return http.StatusForbidden, nil
-	}
-
-	result := &settingsGetRequest{
-		Commands:  c.Commands,
-		StaticGen: []option{},
-		CSS:       c.CSS,
-	}
-
-	if c.StaticGen != nil {
-		t := reflect.TypeOf(c.StaticGen).Elem()
-
-		for i := 0; i < t.NumField(); i++ {
-			if t.Field(i).Name[0] == bytes.ToLower([]byte{t.Field(i).Name[0]})[0] {
-				continue
-			}
-
-			result.StaticGen = append(result.StaticGen, option{
-				Variable: t.Field(i).Name,
-				Name:     t.Field(i).Tag.Get("name"),
-				Value:    reflect.ValueOf(c.StaticGen).Elem().FieldByName(t.Field(i).Name).Interface(),
-			})
-		}
-	}
-
-	return renderJSON(w, result)
-}
-
-func settingsPutHandler(c *fb.Context, w http.ResponseWriter, r *http.Request) (int, error) {
-	if !c.User.Admin {
-		return http.StatusForbidden, nil
-	}
-
-	mod, err := parsePutSettingsRequest(r)
-	if err != nil {
-		return http.StatusBadRequest, err
-	}
-
-	// Update the commands.
-	if mod.Which == "commands" {
-		if err := c.Store.Config.Save("commands", mod.Data.Commands); err != nil {
-			return http.StatusInternalServerError, err
-		}
-
-		c.Commands = mod.Data.Commands
-		return http.StatusOK, nil
-	}
-
-	// Update the global CSS.
-	if mod.Which == "css" {
-		if err := c.Store.Config.Save("css", mod.Data.CSS); err != nil {
-			return http.StatusInternalServerError, err
-		}
-
-		c.CSS = mod.Data.CSS
-		return http.StatusOK, nil
-	}
-
-	// Update the static generator options.
-	if mod.Which == "staticGen" {
-		err = mapstructure.Decode(mod.Data.StaticGen, c.StaticGen)
-		if err != nil {
-			return http.StatusInternalServerError, err
-		}
-
-		err = c.Store.Config.Save("staticgen_"+c.StaticGen.Name(), c.StaticGen)
-		if err != nil {
-			return http.StatusInternalServerError, err
-		}
-
-		return http.StatusOK, nil
-	}
-
-	return http.StatusMethodNotAllowed, nil
-}