Tiny library to distinguish absolute paths from string in Go
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Tiny Absolute Path Library

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abspath is a tiny library to handle file paths a bit better.

In golang, a file path is represented with string (path/filepath standard library is provided).

However, treating file paths with string has some problems. We always go wrong between absolute paths and relative paths. When we create an API which takes a file path, we always need to take care about the parameter (It takes relative path? absolute path? or both of them?). Or we need to design and implement the API to take both the absolute path and relative path.

I don't want to write a program caring about that throughout a program. So I created a type to represent an absolute path. It's just a wrapper of string.

type AbsPath struct {
    underlying string

It's further obvious because its type name is descriptive. And it can't be relative path. For example,

func writeSomethingTo(path AbsPath) error

when we see this API, we can know the path parameter is an absolute path, not a relative path. And we can't fail to pass a relative path to above API because it never accept relative paths.

// Error with 'cannot use a (type AbsPath) as type string in argument'

In addition, AbsPath is kept clean.


$ go get github.com/rhysd/abspath


Create AbsPath Instance

import github.com/rhysd/abspath

var a abspath.AbsPath
var err error

// From a string representing absolute path.
// If it doesn't stand for absolute path, an error will be returned.
a, err = abspath.New("/absolute/path")

// Expanded to $PWD/relative_path
a, err = abspath.ExpandFrom("relative_path")

// Expanded to $HOME/relative_path
a, err = abspath.ExpandFrom("~/relative_path")

// Slashes in the string will be replaced by a file separator.
// In Windows, below can be 'C:\absolute\path'
a, err = abspath.FromSlash("/absoltue/path")

// Similar to ExpandFrom().  But all slashes will be replaced with a file sperator.
a, err = abspath.ExpandFromSlash("relative/path")

// Shortcut of os.Getwd() for AbsPath.
a, err = abspath.Getwd()

// Shortcut for getting an absolute path to home directory.
a, err = abspath.HomeDir()

Operate The Path

AbsPath has some methods deriving function defined in path/filepath standard library. They are helpers to avoid converting between AbsPath and string frequently when you want to use functions in path/filepath package. All method are non-destructive.

For example:

a, _ := abspath.New("/absolute/path")
fmt.Printf("%s\n", a.Dir())
fmt.Printf("%s\n", a.Base())
fmt.Printf("%s\n", a.HasPrefix("/absolute"))

Please see GoDoc for full documentation.

Convert to string

You can simply convert to string by .String() method.

a, _ = abspath.New("/absolute/path")
file.WriteString(a.String())  // 'a' as a string


Distributed under Public Domain 1.0