navidrome/cmd/plugin.go
Deluan Quintão 45c408a674
feat(plugins): allow Plugins to call the Subsonic API (#4260)
* chore: .gitignore any navidrome binary

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: implement internal authentication handling in middleware

Signed-off-by: Deluan <deluan@navidrome.org>

* feat(manager): add SubsonicRouter to Manager for API routing

Signed-off-by: Deluan <deluan@navidrome.org>

* feat(plugins): add SubsonicAPI Host service for plugins and an example plugin

Signed-off-by: Deluan <deluan@navidrome.org>

* fix lint

Signed-off-by: Deluan <deluan@navidrome.org>

* feat(plugins): refactor path handling in SubsonicAPI to extract endpoint correctly

Signed-off-by: Deluan <deluan@navidrome.org>

* docs(plugins): add SubsonicAPI service documentation to README

Signed-off-by: Deluan <deluan@navidrome.org>

* feat(plugins): implement permission checks for SubsonicAPI service

Signed-off-by: Deluan <deluan@navidrome.org>

* feat(plugins): enhance SubsonicAPI service initialization with atomic router handling

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor(plugins): better encapsulated dependency injection

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor(plugins): rename parameter in WithInternalAuth for clarity

Signed-off-by: Deluan <deluan@navidrome.org>

* docs(plugins): update SubsonicAPI permissions section in README for clarity and detail

Signed-off-by: Deluan <deluan@navidrome.org>

* feat(plugins): enhance SubsonicAPI permissions output with allowed usernames and admin flag

Signed-off-by: Deluan <deluan@navidrome.org>

* feat(plugins): add schema reference to example plugins

Signed-off-by: Deluan <deluan@navidrome.org>

* remove import alias

Signed-off-by: Deluan <deluan@navidrome.org>

---------

Signed-off-by: Deluan <deluan@navidrome.org>
2025-06-25 14:18:32 -04:00

717 lines
21 KiB
Go

package cmd
import (
"cmp"
"crypto/sha256"
"encoding/hex"
"fmt"
"io"
"os"
"path/filepath"
"strings"
"text/tabwriter"
"time"
"github.com/navidrome/navidrome/conf"
"github.com/navidrome/navidrome/log"
"github.com/navidrome/navidrome/plugins"
"github.com/navidrome/navidrome/plugins/schema"
"github.com/navidrome/navidrome/utils"
"github.com/navidrome/navidrome/utils/slice"
"github.com/spf13/cobra"
)
const (
pluginPackageExtension = ".ndp"
pluginDirPermissions = 0700
pluginFilePermissions = 0600
)
func init() {
pluginCmd := &cobra.Command{
Use: "plugin",
Short: "Manage Navidrome plugins",
Long: "Commands for managing Navidrome plugins",
}
listCmd := &cobra.Command{
Use: "list",
Short: "List installed plugins",
Long: "List all installed plugins with their metadata",
Run: pluginList,
}
infoCmd := &cobra.Command{
Use: "info [pluginPackage|pluginName]",
Short: "Show details of a plugin",
Long: "Show detailed information about a plugin package (.ndp file) or an installed plugin",
Args: cobra.ExactArgs(1),
Run: pluginInfo,
}
installCmd := &cobra.Command{
Use: "install [pluginPackage]",
Short: "Install a plugin from a .ndp file",
Long: "Install a Navidrome Plugin Package (.ndp) file",
Args: cobra.ExactArgs(1),
Run: pluginInstall,
}
removeCmd := &cobra.Command{
Use: "remove [pluginName]",
Short: "Remove an installed plugin",
Long: "Remove a plugin by name",
Args: cobra.ExactArgs(1),
Run: pluginRemove,
}
updateCmd := &cobra.Command{
Use: "update [pluginPackage]",
Short: "Update an existing plugin",
Long: "Update an installed plugin with a new version from a .ndp file",
Args: cobra.ExactArgs(1),
Run: pluginUpdate,
}
refreshCmd := &cobra.Command{
Use: "refresh [pluginName]",
Short: "Reload a plugin without restarting Navidrome",
Long: "Reload and recompile a plugin without needing to restart Navidrome",
Args: cobra.ExactArgs(1),
Run: pluginRefresh,
}
devCmd := &cobra.Command{
Use: "dev [folder_path]",
Short: "Create symlink to development folder",
Long: "Create a symlink from a plugin development folder to the plugins directory for easier development",
Args: cobra.ExactArgs(1),
Run: pluginDev,
}
pluginCmd.AddCommand(listCmd, infoCmd, installCmd, removeCmd, updateCmd, refreshCmd, devCmd)
rootCmd.AddCommand(pluginCmd)
}
// Validation helpers
func validatePluginPackageFile(path string) error {
if !utils.FileExists(path) {
return fmt.Errorf("plugin package not found: %s", path)
}
if filepath.Ext(path) != pluginPackageExtension {
return fmt.Errorf("not a valid plugin package: %s (expected %s extension)", path, pluginPackageExtension)
}
return nil
}
func validatePluginDirectory(pluginsDir, pluginName string) (string, error) {
pluginDir := filepath.Join(pluginsDir, pluginName)
if !utils.FileExists(pluginDir) {
return "", fmt.Errorf("plugin not found: %s (path: %s)", pluginName, pluginDir)
}
return pluginDir, nil
}
func resolvePluginPath(pluginDir string) (resolvedPath string, isSymlink bool, err error) {
// Check if it's a directory or a symlink
lstat, err := os.Lstat(pluginDir)
if err != nil {
return "", false, fmt.Errorf("failed to stat plugin: %w", err)
}
isSymlink = lstat.Mode()&os.ModeSymlink != 0
if isSymlink {
// Resolve the symlink target
targetDir, err := os.Readlink(pluginDir)
if err != nil {
return "", true, fmt.Errorf("failed to resolve symlink: %w", err)
}
// If target is a relative path, make it absolute
if !filepath.IsAbs(targetDir) {
targetDir = filepath.Join(filepath.Dir(pluginDir), targetDir)
}
// Verify the target exists and is a directory
targetInfo, err := os.Stat(targetDir)
if err != nil {
return "", true, fmt.Errorf("failed to access symlink target %s: %w", targetDir, err)
}
if !targetInfo.IsDir() {
return "", true, fmt.Errorf("symlink target is not a directory: %s", targetDir)
}
return targetDir, true, nil
} else if !lstat.IsDir() {
return "", false, fmt.Errorf("not a valid plugin directory: %s", pluginDir)
}
return pluginDir, false, nil
}
// Package handling helpers
func loadAndValidatePackage(ndpPath string) (*plugins.PluginPackage, error) {
if err := validatePluginPackageFile(ndpPath); err != nil {
return nil, err
}
pkg, err := plugins.LoadPackage(ndpPath)
if err != nil {
return nil, fmt.Errorf("failed to load plugin package: %w", err)
}
return pkg, nil
}
func extractAndSetupPlugin(ndpPath, targetDir string) error {
if err := plugins.ExtractPackage(ndpPath, targetDir); err != nil {
return fmt.Errorf("failed to extract plugin package: %w", err)
}
ensurePluginDirPermissions(targetDir)
return nil
}
// Display helpers
func displayPluginTableRow(w *tabwriter.Writer, discovery plugins.PluginDiscoveryEntry) {
if discovery.Error != nil {
// Handle global errors (like directory read failure)
if discovery.ID == "" {
log.Error("Failed to read plugins directory", "folder", conf.Server.Plugins.Folder, discovery.Error)
return
}
// Handle individual plugin errors - show them in the table
fmt.Fprintf(w, "%s\tERROR\tERROR\tERROR\tERROR\t%v\n", discovery.ID, discovery.Error)
return
}
// Mark symlinks with an indicator
nameDisplay := discovery.Manifest.Name
if discovery.IsSymlink {
nameDisplay = nameDisplay + " (dev)"
}
// Convert capabilities to strings
capabilities := slice.Map(discovery.Manifest.Capabilities, func(cap schema.PluginManifestCapabilitiesElem) string {
return string(cap)
})
fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\t%s\n",
discovery.ID,
nameDisplay,
cmp.Or(discovery.Manifest.Author, "-"),
cmp.Or(discovery.Manifest.Version, "-"),
strings.Join(capabilities, ", "),
cmp.Or(discovery.Manifest.Description, "-"))
}
func displayTypedPermissions(permissions schema.PluginManifestPermissions, indent string) {
if permissions.Http != nil {
fmt.Printf("%shttp:\n", indent)
fmt.Printf("%s Reason: %s\n", indent, permissions.Http.Reason)
fmt.Printf("%s Allow Local Network: %t\n", indent, permissions.Http.AllowLocalNetwork)
fmt.Printf("%s Allowed URLs:\n", indent)
for urlPattern, methodEnums := range permissions.Http.AllowedUrls {
methods := make([]string, len(methodEnums))
for i, methodEnum := range methodEnums {
methods[i] = string(methodEnum)
}
fmt.Printf("%s %s: [%s]\n", indent, urlPattern, strings.Join(methods, ", "))
}
fmt.Println()
}
if permissions.Config != nil {
fmt.Printf("%sconfig:\n", indent)
fmt.Printf("%s Reason: %s\n", indent, permissions.Config.Reason)
fmt.Println()
}
if permissions.Scheduler != nil {
fmt.Printf("%sscheduler:\n", indent)
fmt.Printf("%s Reason: %s\n", indent, permissions.Scheduler.Reason)
fmt.Println()
}
if permissions.Websocket != nil {
fmt.Printf("%swebsocket:\n", indent)
fmt.Printf("%s Reason: %s\n", indent, permissions.Websocket.Reason)
fmt.Printf("%s Allow Local Network: %t\n", indent, permissions.Websocket.AllowLocalNetwork)
fmt.Printf("%s Allowed URLs: [%s]\n", indent, strings.Join(permissions.Websocket.AllowedUrls, ", "))
fmt.Println()
}
if permissions.Cache != nil {
fmt.Printf("%scache:\n", indent)
fmt.Printf("%s Reason: %s\n", indent, permissions.Cache.Reason)
fmt.Println()
}
if permissions.Artwork != nil {
fmt.Printf("%sartwork:\n", indent)
fmt.Printf("%s Reason: %s\n", indent, permissions.Artwork.Reason)
fmt.Println()
}
if permissions.Subsonicapi != nil {
allowedUsers := "All Users"
if len(permissions.Subsonicapi.AllowedUsernames) > 0 {
allowedUsers = strings.Join(permissions.Subsonicapi.AllowedUsernames, ", ")
}
fmt.Printf("%ssubsonicapi:\n", indent)
fmt.Printf("%s Reason: %s\n", indent, permissions.Subsonicapi.Reason)
fmt.Printf("%s Allow Admins: %t\n", indent, permissions.Subsonicapi.AllowAdmins)
fmt.Printf("%s Allowed Usernames: [%s]\n", indent, allowedUsers)
fmt.Println()
}
}
func displayPluginDetails(manifest *schema.PluginManifest, fileInfo *pluginFileInfo, permInfo *pluginPermissionInfo) {
fmt.Println("\nPlugin Information:")
fmt.Printf(" Name: %s\n", manifest.Name)
fmt.Printf(" Author: %s\n", manifest.Author)
fmt.Printf(" Version: %s\n", manifest.Version)
fmt.Printf(" Description: %s\n", manifest.Description)
fmt.Print(" Capabilities: ")
capabilities := make([]string, len(manifest.Capabilities))
for i, cap := range manifest.Capabilities {
capabilities[i] = string(cap)
}
fmt.Print(strings.Join(capabilities, ", "))
fmt.Println()
// Display manifest permissions using the typed permissions
fmt.Println(" Required Permissions:")
displayTypedPermissions(manifest.Permissions, " ")
// Print file information if available
if fileInfo != nil {
fmt.Println("Package Information:")
fmt.Printf(" File: %s\n", fileInfo.path)
fmt.Printf(" Size: %d bytes (%.2f KB)\n", fileInfo.size, float64(fileInfo.size)/1024)
fmt.Printf(" SHA-256: %s\n", fileInfo.hash)
fmt.Printf(" Modified: %s\n", fileInfo.modTime.Format(time.RFC3339))
}
// Print file permissions information if available
if permInfo != nil {
fmt.Println("File Permissions:")
fmt.Printf(" Plugin Directory: %s (%s)\n", permInfo.dirPath, permInfo.dirMode)
if permInfo.isSymlink {
fmt.Printf(" Symlink Target: %s (%s)\n", permInfo.targetPath, permInfo.targetMode)
}
fmt.Printf(" Manifest File: %s\n", permInfo.manifestMode)
if permInfo.wasmMode != "" {
fmt.Printf(" WASM File: %s\n", permInfo.wasmMode)
}
}
}
type pluginFileInfo struct {
path string
size int64
hash string
modTime time.Time
}
type pluginPermissionInfo struct {
dirPath string
dirMode string
isSymlink bool
targetPath string
targetMode string
manifestMode string
wasmMode string
}
func getFileInfo(path string) *pluginFileInfo {
fileInfo, err := os.Stat(path)
if err != nil {
log.Error("Failed to get file information", err)
return nil
}
return &pluginFileInfo{
path: path,
size: fileInfo.Size(),
hash: calculateSHA256(path),
modTime: fileInfo.ModTime(),
}
}
func getPermissionInfo(pluginDir string) *pluginPermissionInfo {
// Get plugin directory permissions
dirInfo, err := os.Lstat(pluginDir)
if err != nil {
log.Error("Failed to get plugin directory permissions", err)
return nil
}
permInfo := &pluginPermissionInfo{
dirPath: pluginDir,
dirMode: dirInfo.Mode().String(),
}
// Check if it's a symlink
if dirInfo.Mode()&os.ModeSymlink != 0 {
permInfo.isSymlink = true
// Get target path and permissions
targetPath, err := os.Readlink(pluginDir)
if err == nil {
if !filepath.IsAbs(targetPath) {
targetPath = filepath.Join(filepath.Dir(pluginDir), targetPath)
}
permInfo.targetPath = targetPath
if targetInfo, err := os.Stat(targetPath); err == nil {
permInfo.targetMode = targetInfo.Mode().String()
}
}
}
// Get manifest file permissions
manifestPath := filepath.Join(pluginDir, "manifest.json")
if manifestInfo, err := os.Stat(manifestPath); err == nil {
permInfo.manifestMode = manifestInfo.Mode().String()
}
// Get WASM file permissions (look for .wasm files)
entries, err := os.ReadDir(pluginDir)
if err == nil {
for _, entry := range entries {
if filepath.Ext(entry.Name()) == ".wasm" {
wasmPath := filepath.Join(pluginDir, entry.Name())
if wasmInfo, err := os.Stat(wasmPath); err == nil {
permInfo.wasmMode = wasmInfo.Mode().String()
break // Just show the first WASM file found
}
}
}
}
return permInfo
}
// Command implementations
func pluginList(cmd *cobra.Command, args []string) {
discoveries := plugins.DiscoverPlugins(conf.Server.Plugins.Folder)
w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
fmt.Fprintln(w, "ID\tNAME\tAUTHOR\tVERSION\tCAPABILITIES\tDESCRIPTION")
for _, discovery := range discoveries {
displayPluginTableRow(w, discovery)
}
w.Flush()
}
func pluginInfo(cmd *cobra.Command, args []string) {
path := args[0]
pluginsDir := conf.Server.Plugins.Folder
var manifest *schema.PluginManifest
var fileInfo *pluginFileInfo
var permInfo *pluginPermissionInfo
if filepath.Ext(path) == pluginPackageExtension {
// It's a package file
pkg, err := loadAndValidatePackage(path)
if err != nil {
log.Fatal("Failed to load plugin package", err)
}
manifest = pkg.Manifest
fileInfo = getFileInfo(path)
// No permission info for package files
} else {
// It's a plugin name
pluginDir, err := validatePluginDirectory(pluginsDir, path)
if err != nil {
log.Fatal("Plugin validation failed", err)
}
manifest, err = plugins.LoadManifest(pluginDir)
if err != nil {
log.Fatal("Failed to load plugin manifest", err)
}
// Get permission info for installed plugins
permInfo = getPermissionInfo(pluginDir)
}
displayPluginDetails(manifest, fileInfo, permInfo)
}
func pluginInstall(cmd *cobra.Command, args []string) {
ndpPath := args[0]
pluginsDir := conf.Server.Plugins.Folder
pkg, err := loadAndValidatePackage(ndpPath)
if err != nil {
log.Fatal("Package validation failed", err)
}
// Create target directory based on plugin name
targetDir := filepath.Join(pluginsDir, pkg.Manifest.Name)
// Check if plugin already exists
if utils.FileExists(targetDir) {
log.Fatal("Plugin already installed", "name", pkg.Manifest.Name, "path", targetDir,
"use", "navidrome plugin update")
}
if err := extractAndSetupPlugin(ndpPath, targetDir); err != nil {
log.Fatal("Plugin installation failed", err)
}
fmt.Printf("Plugin '%s' v%s installed successfully\n", pkg.Manifest.Name, pkg.Manifest.Version)
}
func pluginRemove(cmd *cobra.Command, args []string) {
pluginName := args[0]
pluginsDir := conf.Server.Plugins.Folder
pluginDir, err := validatePluginDirectory(pluginsDir, pluginName)
if err != nil {
log.Fatal("Plugin validation failed", err)
}
_, isSymlink, err := resolvePluginPath(pluginDir)
if err != nil {
log.Fatal("Failed to resolve plugin path", err)
}
if isSymlink {
// For symlinked plugins (dev mode), just remove the symlink
if err := os.Remove(pluginDir); err != nil {
log.Fatal("Failed to remove plugin symlink", "name", pluginName, err)
}
fmt.Printf("Development plugin symlink '%s' removed successfully (target directory preserved)\n", pluginName)
} else {
// For regular plugins, remove the entire directory
if err := os.RemoveAll(pluginDir); err != nil {
log.Fatal("Failed to remove plugin directory", "name", pluginName, err)
}
fmt.Printf("Plugin '%s' removed successfully\n", pluginName)
}
}
func pluginUpdate(cmd *cobra.Command, args []string) {
ndpPath := args[0]
pluginsDir := conf.Server.Plugins.Folder
pkg, err := loadAndValidatePackage(ndpPath)
if err != nil {
log.Fatal("Package validation failed", err)
}
// Check if plugin exists
targetDir := filepath.Join(pluginsDir, pkg.Manifest.Name)
if !utils.FileExists(targetDir) {
log.Fatal("Plugin not found", "name", pkg.Manifest.Name, "path", targetDir,
"use", "navidrome plugin install")
}
// Create a backup of the existing plugin
backupDir := targetDir + ".bak." + time.Now().Format("20060102150405")
if err := os.Rename(targetDir, backupDir); err != nil {
log.Fatal("Failed to backup existing plugin", err)
}
// Extract the new package
if err := extractAndSetupPlugin(ndpPath, targetDir); err != nil {
// Restore backup if extraction failed
os.RemoveAll(targetDir)
_ = os.Rename(backupDir, targetDir) // Ignore error as we're already in a fatal path
log.Fatal("Plugin update failed", err)
}
// Remove the backup
os.RemoveAll(backupDir)
fmt.Printf("Plugin '%s' updated to v%s successfully\n", pkg.Manifest.Name, pkg.Manifest.Version)
}
func pluginRefresh(cmd *cobra.Command, args []string) {
pluginName := args[0]
pluginsDir := conf.Server.Plugins.Folder
pluginDir, err := validatePluginDirectory(pluginsDir, pluginName)
if err != nil {
log.Fatal("Plugin validation failed", err)
}
resolvedPath, isSymlink, err := resolvePluginPath(pluginDir)
if err != nil {
log.Fatal("Failed to resolve plugin path", err)
}
if isSymlink {
log.Debug("Processing symlinked plugin", "name", pluginName, "link", pluginDir, "target", resolvedPath)
}
fmt.Printf("Refreshing plugin '%s'...\n", pluginName)
// Get the plugin manager and refresh
mgr := GetPluginManager(cmd.Context())
log.Debug("Scanning plugins directory", "path", pluginsDir)
mgr.ScanPlugins()
log.Info("Waiting for plugin compilation to complete", "name", pluginName)
// Wait for compilation to complete
if err := mgr.EnsureCompiled(pluginName); err != nil {
log.Fatal("Failed to compile refreshed plugin", "name", pluginName, err)
}
log.Info("Plugin compilation completed successfully", "name", pluginName)
fmt.Printf("Plugin '%s' refreshed successfully\n", pluginName)
}
func pluginDev(cmd *cobra.Command, args []string) {
sourcePath, err := filepath.Abs(args[0])
if err != nil {
log.Fatal("Invalid path", "path", args[0], err)
}
pluginsDir := conf.Server.Plugins.Folder
// Validate source directory and manifest
if err := validateDevSource(sourcePath); err != nil {
log.Fatal("Source validation failed", err)
}
// Load manifest to get plugin name
manifest, err := plugins.LoadManifest(sourcePath)
if err != nil {
log.Fatal("Failed to load plugin manifest", "path", filepath.Join(sourcePath, "manifest.json"), err)
}
pluginName := cmp.Or(manifest.Name, filepath.Base(sourcePath))
targetPath := filepath.Join(pluginsDir, pluginName)
// Handle existing target
if err := handleExistingTarget(targetPath, sourcePath); err != nil {
log.Fatal("Failed to handle existing target", err)
}
// Create target directory if needed
if err := os.MkdirAll(filepath.Dir(targetPath), 0755); err != nil {
log.Fatal("Failed to create plugins directory", "path", filepath.Dir(targetPath), err)
}
// Create the symlink
if err := os.Symlink(sourcePath, targetPath); err != nil {
log.Fatal("Failed to create symlink", "source", sourcePath, "target", targetPath, err)
}
fmt.Printf("Development symlink created: '%s' -> '%s'\n", targetPath, sourcePath)
fmt.Println("Plugin can be refreshed with: navidrome plugin refresh", pluginName)
}
// Utility functions
func validateDevSource(sourcePath string) error {
sourceInfo, err := os.Stat(sourcePath)
if err != nil {
return fmt.Errorf("source folder not found: %s (%w)", sourcePath, err)
}
if !sourceInfo.IsDir() {
return fmt.Errorf("source path is not a directory: %s", sourcePath)
}
manifestPath := filepath.Join(sourcePath, "manifest.json")
if !utils.FileExists(manifestPath) {
return fmt.Errorf("source folder missing manifest.json: %s", sourcePath)
}
return nil
}
func handleExistingTarget(targetPath, sourcePath string) error {
if !utils.FileExists(targetPath) {
return nil // Nothing to handle
}
// Check if it's already a symlink to our source
existingLink, err := os.Readlink(targetPath)
if err == nil && existingLink == sourcePath {
fmt.Printf("Symlink already exists and points to the correct source\n")
return fmt.Errorf("symlink already exists") // This will cause early return in caller
}
// Handle case where target exists but is not a symlink to our source
fmt.Printf("Target path '%s' already exists.\n", targetPath)
fmt.Print("Do you want to replace it? (y/N): ")
var response string
_, err = fmt.Scanln(&response)
if err != nil || strings.ToLower(response) != "y" {
if err != nil {
log.Debug("Error reading input, assuming 'no'", err)
}
return fmt.Errorf("operation canceled")
}
// Remove existing target
if err := os.RemoveAll(targetPath); err != nil {
return fmt.Errorf("failed to remove existing target %s: %w", targetPath, err)
}
return nil
}
func ensurePluginDirPermissions(dir string) {
if err := os.Chmod(dir, pluginDirPermissions); err != nil {
log.Error("Failed to set plugin directory permissions", "dir", dir, err)
}
// Apply permissions to all files in the directory
entries, err := os.ReadDir(dir)
if err != nil {
log.Error("Failed to read plugin directory", "dir", dir, err)
return
}
for _, entry := range entries {
path := filepath.Join(dir, entry.Name())
info, err := os.Stat(path)
if err != nil {
log.Error("Failed to stat file", "path", path, err)
continue
}
mode := os.FileMode(pluginFilePermissions) // Files
if info.IsDir() {
mode = os.FileMode(pluginDirPermissions) // Directories
ensurePluginDirPermissions(path) // Recursive
}
if err := os.Chmod(path, mode); err != nil {
log.Error("Failed to set file permissions", "path", path, err)
}
}
}
func calculateSHA256(filePath string) string {
file, err := os.Open(filePath)
if err != nil {
log.Error("Failed to open file for hashing", err)
return "N/A"
}
defer file.Close()
hasher := sha256.New()
if _, err := io.Copy(hasher, file); err != nil {
log.Error("Failed to calculate hash", err)
return "N/A"
}
return hex.EncodeToString(hasher.Sum(nil))
}