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os/user

一般情况下我们可以使用 os/user 包提供的 Current() 函数来获取用户信息：

user, err := user.Current()
if nil == err {
	return user.HomeDir, nil
}

但这个方式交叉编译后不能完全跨平台，在 darwin 下需要 cgo 才能正常工作。

改进

为了解决这个问题，我们需要进行一点增强，在通过 os/user 获取失败时再通过环境变量、命令来获取：

// Home returns the home directory for the executing user.
//
// This uses an OS-specific method for discovering the home directory.
// An error is returned if a home directory cannot be detected.
func Home() (string, error) {
	user, err := user.Current()
	if nil == err {
		return user.HomeDir, nil
	}

	// cross compile support
    
	if "windows" == runtime.GOOS {
		return homeWindows()
	}

	// Unix-like system, so just assume Unix
	return homeUnix()
}

func homeUnix() (string, error) {
	// First prefer the HOME environmental variable
	if home := os.Getenv("HOME"); home != "" {
		return home, nil
	}

	// If that fails, try the shell
	var stdout bytes.Buffer
	cmd := exec.Command("sh", "-c", "eval echo ~$USER")
	cmd.Stdout = &stdout
	if err := cmd.Run(); err != nil {
		return "", err
	}

	result := strings.TrimSpace(stdout.String())
	if result == "" {
		return "", errors.New("blank output when reading home directory")
	}

	return result, nil
}

func homeWindows() (string, error) {
	drive := os.Getenv("HOMEDRIVE")
	path := os.Getenv("HOMEPATH")
	home := drive + path
	if drive == "" || path == "" {
		home = os.Getenv("USERPROFILE")
	}
	if home == "" {
		return "", errors.New("HOMEDRIVE, HOMEPATH, and USERPROFILE are blank")
	}

	return home, nil
}

参考

• Obtain user's home directory
• go-homedir
• 一些有用的工具函数