SFTP Client

An Elixir SFTP Client that wraps Erlang's ssh and ssh_sftp.

Prerequisites

• Erlang 20 or greater
• Elixir 1.8 or greater

Installation

The package can be installed by adding :sftp_client to your list of dependencies in mix.exs:

def deps do
  [
    {:sftp_client, "~> 1.4"}
  ]
end

Usage

There are bang (!) counterparts for almost all available functions.

Connect & Disconnect

To open a new connection to an SFTP server:

{:ok, conn} = SFTPClient.connect(host: "ftp.myhost.com")

Due to a change in OTP 24 that removed automatic public key lookup in the sftp module you may need to define the modify_algorithms option to avoid "Key exchange failed" errors:

{:ok, conn} = SFTPClient.connect(
  host: "ftp.myhost.com",
  modify_algorithms: [
    append: [
      public_key: [:"ssh-rsa"]
    ]
  ]
)

Refer to the docs for SFTPClient.Operations.Connect.connect/1 to find out all available options.

It is strongly recommended to close a connection after your operations have completed:

SFTPClient.disconnect(conn)

For short-lived connections you can also use a function as second argument. After the function body has run or raises, the connection is automatically closed.

SFTPClient.connect([host: "ftp.myhost.com"], fn conn ->
  # Do something with conn
end)

Download

To download a file from the server you can use the following function.

SFTPClient.download_file(conn, "my/remote/dir/file.jpg", "my/dir/local-file.jpg")
# => {:ok, "my/dir/local-file.jpg"}

When the third argument is an existing directory on your file system, the file is downloaded to a file with the same name as the one on the server.

SFTPClient.download_file(conn, "my/remote/dir/image.png", "my/local/dir")
# => {:ok, "my/local/dir/image.png"}

It is also possible to use Streams to download data into a file or memory.

source_stream = SFTPClient.stream_file!(conn, "my/remote/file.jpg")
target_stream = File.stream!("my/local/file.jpg")

source_stream
|> Stream.into(target_stream)
|> Stream.run()

Upload

To upload are file from the file system you can use the following function.

SFTPClient.upload_file(conn, "my/local/dir/file.jpg", "my/remote/dir/file.jpg")
# => {:ok, "my/remote/dir/file.jpg"}

You can also use Streams to upload data. Please make sure to set a proper chunk size or the upload may be very slow.

source_stream = File.stream!("my/local/file.jpg", [], 32_768)
target_stream = SFTPClient.stream_file!(conn, "my/remote/file.jpg")

source_stream
|> Stream.into(target_stream)
|> Stream.run()

List Directory

SFTPClient.list_dir(conn, "my/dir")
# => {:ok, ["my/dir/file_1.jpg", "my/dir/file_2.jpg", ...]}

Create Directory

SFTPClient.make_dir(conn, "my/new/dir")

Note that this operation fails unless the parent directory exists.

Delete

To delete a file:

SFTPClient.delete_file(conn, "my/remote/file.jpg")

To delete a directory:

SFTPClient.delete_dir(conn, "my/remote/dir")

Note that a directory cannot be deleted as long as it still contains files.

Rename

To move/rename a file or directory:

SFTPClient.rename(conn, "my/remote/file.jpg", "my/remote/new-file.jpg")

File Info

You can retrieve meta data about a file from the server such as file size, modification time, file permissions, owner and so on.

SFTPClient.file_info(conn, "my/remote/file.jpg")
# => {:ok, %File.Stat{...}}

Refer to the File.Stat docs for a list of available file information.

Symbolic Links

There are also a couple of functions that handle symlinks.

It is possible to get the target of a symlink.

SFTPClient.read_link(conn, "my/remote/link.jpg")
# => {:ok, "my/remote/file.jpg"}

You can retrieve meta data about symlinks, similar to file_info/2.

SFTPClient.link_info(conn, "my/remote/link.jpg")
# => {:ok, %File.Stat{...}}

And you are able to create symlinks.

SFTPClient.make_link(conn, "my/remote/link.jpg", "my/remote/file.jpg")

License

This library is released under the MIT License. See the LICENSE.md file for further details.