s3browser-backend/internal/types/id.go

package types

import (
	"fmt"
	"path/filepath"
	"regexp"
	"strings"
)

var (
	idRegex = regexp.MustCompile(`(.*?)(@(.*))?:(.*)`)
)

// ID an id of a file consists of at least a Bucket and a Key. Version is optional.
// Can also be used as an ID for a directory. When the key ends with "/" it is treated as dir.
type ID struct {
	Bucket  string `json:"bucket"`  // Name of the bucket
	Key     string `json:"key"`     // Key of the object
	Version string `json:"version"` // Version of the object. For now we ignore it
}

// String Return String representation of an ID
// Looks like this: "bucketName@version:/id/of/obj" or "bucketName:/id/of/obj"
func (i ID) String() string {
	if i.Version == "" {
		return fmt.Sprintf("%s:%s", i.Bucket, i.Key)
	} else {
		return fmt.Sprintf("%s@%s:%s", i.Bucket, i.Version, i.Key)
	}
}

// Normalize normalzes the key to have a "/" prefix
func (i *ID) Normalize() {
	if i.Key == "." {
		i.Key = "/"
	} else if !strings.HasPrefix(i.Key, "/") {
		i.Key = "/" + i.Key
	}
}

// Valid checks if bucket and key is not empty
func (i *ID) Valid() bool {
	return i.Bucket != "" && i.Key != ""
}

func (i *ID) IsDirectory() bool {
	return strings.HasSuffix(i.Key, "/")
}

// Raw for the Key interface for the dataloaders so ID can be used as a dataloader key
func (i ID) Raw() interface{} {
	return i
}

// Parent returns the parent dir ID. If its a file then return containing directory.
// If this is a directory then return the dir one up.
func (i ID) Parent() *ID {
	if i.Key == "/" {
		// Already at root. We dont have a parent
		return nil
	}

	var parent *ID

	if i.IsDirectory() {
		parts := strings.Split(i.Key, "/")
		parent = &ID{
			Bucket: i.Bucket,
			Key:    strings.Join(parts[:len(parts)-2], "/") + "/",
		}
	} else {
		dir := filepath.Dir(i.Key)

		if dir != "/" {
			dir += "/"
		}

		parent = &ID{
			Bucket: i.Bucket,
			Key:    dir,
		}
	}

	parent.Normalize()

	return parent
}

// Name returns filename or directory name
func (i ID) Name() string {
	return filepath.Base(i.Key)
}

// ParseID parses a string to an ID. Null if invalid
func ParseID(id string) *ID {
	match := idRegex.FindStringSubmatch(id)
	if match == nil {
		return nil
	}

	rtn := &ID{
		Bucket:  match[1],
		Version: match[3],
		Key:     match[4],
	}

	if !rtn.Valid() {
		return nil
	}

	rtn.Normalize()

	return rtn
}