tempdir.cr

Creates a temporary directory with atomic mkdtemp/mkstemp support.

Features

• Atomic creation: Uses mkdtemp on Unix and CreateFileA on Windows for race-free temp directory/file creation
• Secure permissions: Directories created with 0o700, files with 0o600 (owner-only)
• Cross-platform: Works on Unix/Linux/macOS and Windows
• Convenience methods: create_tempfile for atomic tempfile creation inside temp directories
• Automatic cleanup: Tempdir removes contents on #close, block form auto-cleans

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     tempdir:
       github: kritoke/tempdir
   

2. Run shards install

Usage

require "tempdir"

Dir.mktmpdir

dir = Dir.mktmpdir(*args)

Creates a temporary directory. Arguments are passed to File.tempname as-is. See File.tempname.

The returning object is Tempdir. It removes all entries when #close-d.

With block, the created directory will be removed after block is left.

Dir.mktmpdir do |dir|
  # work with dir
end

Tempdir

The temporary directory class based on Dir.

This class only rewrites the #close method to remove entries in the directory.

create_tempfile

Create a secure tempfile inside the tempdir using atomic mkstemp:

Dir.mktmpdir do |dir|
  path = dir.create_tempfile("myfile_", data: Slice(UInt8).new([1, 2, 3]))
  # path is the created file path with 0o600 permissions
end

The data parameter is optional. If provided, writes the bytes atomically. The file is created with owner-only permissions (0o600) where supported.

Security

• Directories are created with 0o700 permissions (owner-only).
• Files created via create_tempfile use mkstemp for atomic creation and are set to 0o600 (owner read/write only).
• On Unix, uses mkdtemp/mkstemp for atomic creation avoiding TOCTOU races.
• On Windows, falls back to CreateFileA with CREATE_NEW flag for atomic semantics.

Development

crystal spec

Contributing

1. Fork it (https://github.com/kritoke/tempdir/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

License

MIT