FTP with Erlang FTP client

Questions / Help
1

Hi,
I’ve seen a couple of examples using the Erlang FTP client from Elixir and I have succesfully stepped through an example but now I’m stuck.
I keep getting an {:error, :epath} error although the file is there.

ftp_target_directory = ftp_target_directory |> String.to_charlist
ftp_host = Config.get(:importer, :ftp_host) |> String.to_charlist
ftp_user = Config.get(:importer, :ftp_user) |> String.to_charlist
ftp_pass = Config.get(:importer, :ftp_pass) |> String.to_charlist

Logger.info("Downloading files from #{inspect ftp_host} to #{inspect ftp_target_directory}")

:application.start :inets 
{:ok, pid} = :inets.start(:ftpc, host: ftp_host)
:ftp.user(pid, ftp_user, ftp_pass)
:ftp.pwd(pid)
:ftp.lcd(pid, ftp_target_directory)
:ftp.type(pid, :binary)
directory_list = get_listing(pid)
Enum.each(directory_list, fn directory ->
    :ftp.cd(pid, directory)
    files = get_listing(pid)
    Enum.each(files, fn file ->
      Logger.info("Downloading #{inspect file}")
      status = :ftp.recv(pid, file)
      Logger.info("Status #{inspect status}")
    end) 
    :ftp.cd(pid, '..')
end)
end

defp get_listing(pid) do
   {:ok, listing} = :ftp.nlist(pid)
   listing = listing |> String.Chars.List.to_string |> String.split("\r\n", trim: true)
   Enum.map(listing, fn item -> String.to_char_list(item) end)
end

I’ve put the client in verbose mode but I can’t see the client actually requesting the file, all I get is the error above.
I’m using the bitwalker/alpine-erlang:6.1 with elixir 1.4.

iex(testdownload@127.0.0.1)6> {:ok, pid} = :inets.start(:ftpc, host: ftp_host, verbose: true)
\n220 Welcome to the FTP Service."er (v. 7.2.0)
{:ok, #PID<0.647.0>}
iex(testdownload@127.0.0.1)7> :ftp.user(pid, ftp_user, ftp_pass)
“Sending: USER secret”
“Receiving: 331 Password required for secret”
“Sending: PASS secretpass”
“Receiving: 230 Logon OK. Proceed.”
:ok
iex(testdownload@127.0.0.1)8> :ftp.pwd(pid)
“Sending: PWD”
“Receiving: 257 “/” is current directory.”
{:ok, ‘/’}
iex(testdownload@127.0.0.1)9> :ftp.lcd(pid, ftp_target_directory)
:ok
iex(testdownload@127.0.0.1)10> :ftp.type(pid, :binary)
“Sending: TYPE I”
“Receiving: 200 Type set to I”
:ok
iex(testdownload@127.0.0.1)11> :ftp.cd(pid, ‘files’)
“Sending: CWD files”
“Receiving: 250 CWD command successful.”
:ok
iex(testdownload@127.0.0.1)14> :ftp.nlist(pid)
“Sending: PASV”
“Receiving: 227 Entering Passive Mode (147,14,4,15,156,195)”
“Sending: NLST”
“Receiving: 150 Opening data connection for file list.”
“Receiving: 226 Transfer complete.”
{:ok, ‘file.csv\r\n’}
iex(testdownload@127.0.0.1)12> :ftp.recv(pid, ‘file.csv’)
{:error, :epath}

Can anyone tell me what I’m doing wrong? :slight_smile:

1 Like
2

The error you get is described as foolows:

epath
No such file or directory, or directory already exists, or permission denied.

So have you checked with another FTP client if you can download the file using that one? Also put it in verbose and check if it uses relative path to current dir or full path for RECV, change your code accordingly then.

1 Like
3

Hi,
Thanks for your response.
I’ve successfully downloaded the file with the linux ftp client.
The problem with verbose mode is that when I try recv I get the error right away. It is as if the client doesn’t even issue the command.
I’m completely baffled. :slight_smile:

1 Like
4

Please try to use :ftp.recv/3 and provide a path and filename that you are definitevely allowed to write. I’m not quite sure where BEAM will try to create the file if the third parameter is missing.

2 Likes
5

Just a quick follow up. It was indeed file system rights that were my problem.
I was building the release with a docker mix plugin that used the USER directive in the Dockerfile.
Everything works as expected now.

Thanks for your help!

2 Likes
6

I have also run into this when the ftp server deleted the file before I was able to download it (i.e. between running :ftp.nlist/1 and :ftp.recv/2)

1 Like
7

According to the erlang docs, :epath means: “No such file or directory, or directory already exists, or permission denied.”

The error codes are listed at the bottom of this page: http://erlang.org/documentation/doc-5.2/lib/inets-3.0/doc/html/ftp.html

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