implemented http server

internal/server/SharedLocation.go

@@ -0,0 +1,120 @@
+package server
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+type SharedLocation struct {
+	// relative to config path at first,
+	// then [normalize] makes it absolute
+	Path string `toml:"path"`
+	// [normalize] removes trailing '/'
+	// so "/" becomes ""
+	Url           string `toml:"url"`
+	ReadPassword  string `toml:"read_password"`
+	WritePassword string `toml:"write_password"`
+}
+
+func (sh *SharedLocation) normalize(configDir string) error {
+	if sh.Path == "" {
+		return errors.New("share.path is empty")
+	}
+	// get absolute path for configDir
+	configDirAbs, err := filepath.Abs(configDir)
+	if err != nil {
+		return err
+	}
+	// resolve symlinks
+	configDirAbs, err = filepath.EvalSymlinks(configDirAbs)
+	if err != nil {
+		return err
+	}
+	// fix separators
+	shPathOsSep, err := filepath.Localize(sh.Path)
+	if err != nil {
+		return err
+	}
+	// join configDir with sh.Path
+	sh.Path = filepath.Join(configDirAbs, shPathOsSep)
+
+	if sh.Url == "" {
+		return errors.New("share.url is empty")
+	}
+	if sh.Url[0] != '/' {
+		return errors.New("share.url doesn't start with slash: '" + sh.Url + "'")
+	}
+	// remove trailing slash
+	sh.Url = strings.TrimRight(sh.Url, "/")
+
+	return nil
+}
+
+func (sh *SharedLocation) String() string {
+	var r, w string
+	if sh.ReadPassword == "" {
+		r = "public"
+	} else {
+		r = "password"
+	}
+	if sh.WritePassword == "" {
+		w = "no"
+	} else {
+		w = "password"
+	}
+	url := sh.Url
+	if url == "" {
+		url = "/"
+	}
+	return "share '" + url + "' r:" + r + " w:" + w +
+		" -> '" + sh.Path + "'"
+}
+
+func (sh *SharedLocation) mkdir() error {
+	return os.MkdirAll(sh.Path, 0o755)
+}
+
+type UrlStatus uint32
+
+const (
+	UrlFile = UrlStatus(iota)
+	UrlDir
+	UrlNotFound
+	UrlForbidden
+	UrlIncorrect
+)
+
+// returns calculated path, or input url if it doesn't belong to any share
+func (shares Shares) MapUrl(url string) (string, *SharedLocation, UrlStatus) {
+	if url == "" || url[0] != '/' {
+		return "", nil, UrlIncorrect
+	}
+	for _, sh := range shares {
+		pathInShare, ok := strings.CutPrefix(url, sh.Url)
+		if !ok {
+			continue
+		}
+
+		if pathInShare != "" && pathInShare[0] != '/' {
+			// url is not sh.Url or child of it
+			continue
+		}
+		pathAbs := filepath.Join(sh.Path, filepath.FromSlash(pathInShare))
+
+		fi, err := os.Stat(pathAbs)
+		switch {
+		case errors.Is(err, fs.ErrNotExist):
+			return pathAbs, sh, UrlNotFound
+		case err != nil:
+			return pathAbs, sh, UrlForbidden
+		case fi.IsDir():
+			return pathAbs, sh, UrlDir
+		default:
+			return pathAbs, sh, UrlFile
+		}
+	}
+	return url, nil, UrlNotFound
+}