filebrowser/http/utils.go

124 lines
3.9 KiB
Go

package fbhttp
import (
"encoding/json"
"errors"
"net/http"
"net/url"
"os"
gopath "path"
"path/filepath"
"strings"
libErrors "github.com/filebrowser/filebrowser/v2/errors"
imgErrors "github.com/filebrowser/filebrowser/v2/img"
)
// slashClean canonicalizes a virtual path to the absolute, "/"-separated,
// lexically cleaned form that both the rule checker and the scoped filesystem
// expect.
//
// Paths reach us either verbatim from a request or built by the OS — afero.Walk
// and filepath.Join use "\" on Windows. There the filesystem resolves "\" as a
// separator while the rule checker treated it as an ordinary character, so
// "/allow\..\Secret.txt" evaded a rule for "/Secret.txt" and still opened it.
// Normalizing with the host's own separator makes both layers agree on which
// file a path names, and is a no-op on POSIX, where "\" is a legal character in
// a filename and must stay one.
func slashClean(name string) string {
return cleanSeparators(name, string(filepath.Separator))
}
// canonicalizeRequestPath rewrites the request path to its canonical virtual
// form, so that the filesystem operation, the hook, the stored share record and
// the thumbnail cache key all use the same string the rule check approved.
//
// A trailing separator is preserved: handlers distinguish "/dir/" from "/dir"
// to decide whether to create a directory, and gopath.Clean would drop it.
func canonicalizeRequestPath(r *http.Request) {
p := slashClean(r.URL.Path)
trailing := strings.HasSuffix(r.URL.Path, "/") || strings.HasSuffix(r.URL.Path, string(filepath.Separator))
if p != "/" && trailing {
p += "/"
}
r.URL.Path = p
}
// cleanSeparators is slashClean with the host separator passed in explicitly,
// so the Windows behaviour can be exercised on any platform.
func cleanSeparators(name, sep string) string {
if sep != "/" {
name = strings.ReplaceAll(name, sep, "/")
}
if name == "" || name[0] != '/' {
name = "/" + name
}
return gopath.Clean(name)
}
func renderJSON(w http.ResponseWriter, _ *http.Request, data interface{}) (int, error) {
marsh, err := json.Marshal(data)
if err != nil {
return http.StatusInternalServerError, err
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
if _, err := w.Write(marsh); err != nil {
return http.StatusInternalServerError, err
}
return 0, nil
}
func errToStatus(err error) int {
switch {
case err == nil:
return http.StatusOK
case os.IsPermission(err):
return http.StatusForbidden
case os.IsNotExist(err), errors.Is(err, libErrors.ErrNotExist):
return http.StatusNotFound
case os.IsExist(err), errors.Is(err, libErrors.ErrExist):
return http.StatusConflict
case errors.Is(err, libErrors.ErrPermissionDenied):
return http.StatusForbidden
case errors.Is(err, libErrors.ErrInvalidRequestParams):
return http.StatusBadRequest
case errors.Is(err, libErrors.ErrRootUserDeletion):
return http.StatusForbidden
case errors.Is(err, imgErrors.ErrImageTooLarge):
return http.StatusRequestEntityTooLarge
default:
return http.StatusInternalServerError
}
}
// This is an adaptation if http.StripPrefix in which we don't
// return 404 if the page doesn't have the needed prefix.
func stripPrefix(prefix string, h http.Handler) http.Handler {
if prefix == "" || prefix == "/" {
return h
}
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
p := strings.TrimPrefix(r.URL.Path, prefix)
rp := strings.TrimPrefix(r.URL.RawPath, prefix)
// If the path is exactly the prefix (no trailing slash), redirect to
// the prefix with a trailing slash so the router receives "/" instead
// of "", which would otherwise cause a redirect to the site root.
if p == "" {
http.Redirect(w, r, prefix+"/", http.StatusMovedPermanently)
return
}
r2 := new(http.Request)
*r2 = *r
r2.URL = new(url.URL)
*r2.URL = *r.URL
r2.URL.Path = p
r2.URL.RawPath = rp
h.ServeHTTP(w, r2)
})
}