Alternative FTP client libraries for Erlang

Question

There are at least two HTTP client libraries for Erlang in addition to httpc in the OTP library (which seems to be generally regarded as buggy and clunky): ibrowse and lhttpc. Are there similar alternatives to ftp?

Answer 1

I realize this is an old question, but hopefully others will find this useful:

lftpc is a "Lightweight Erlang FTP Client" modeled after lhttpc and dlhttpc which we have been using in production for the last 6 months or so.

It's not very well documented right now, but here is an example using test.rebex.net:

1> lftpc:start().
ok
2> {ok, {_, _, Socket}} = lftpc:connect("test.rebex.net", 21, []).
{ok,{undefined,{220,[<<"FTP on test.rebex.net ready...">>]},
               <0.65.0>}}
3> lftpc:login(Socket, [{username, <<"demo">>}, {password, <<"password">>}], infinity, []).
{ok,[{undefined,{331,[<<"Password required for demo.">>]},
                undefined},
     {undefined,{230,[<<"User demo logged in.">>]},undefined}]}
4> lftpc:cd(Socket, <<"pub">>, infinity, []).
{ok,{undefined,{250,
                [<<"CWD command successful. \"/pub\" is current directory.">>]},
               undefined}}

By default, there are no decoders used for the control or data connections. So when we list a directory containing 2 files: example and test we get back:

5> lftpc:nlist(Socket, infinity, []).
{ok,{{150,
      [<<"Data connection accepted from 173.198.175.141:53504; transfer starting.">>]},
     {226,[<<"Transfer ok.">>]},
     [<<"example\r\ntest\r\n">>]}}

We can specify a data_decoder:

6> lftpc:nlist(Socket, infinity, [{partial_download, []}, {data_decoder, lftpc_format:nlst_decoder()}]).
{ok,{{150,
      [<<"Data connection accepted from 127.0.0.1:54359; transfer starting.">>]},
     {226,[<<"Transfer ok.">>]},
     [[<<"example">>,<<"test">>]]}}

We can also specify partial_download to receive the data in chunks:

7> {ok, {_, Download}} = lftpc:nlist(Socket, infinity, [{partial_download, []}, {data_decoder, lftpc_format:nlst_decoder()}]).
{ok,{{150,
      [<<"Data connection accepted from 127.0.0.1:54403; transfer starting.">>]},
     <0.86.0>}}
8> receive {data_part, Download, Data} -> Data end.
[<<"example">>,<<"test">>]
9> receive {ftp_eod, Download, Message} -> Message end.
{226,[<<"Transfer ok.">>]}

Take a look at the main src/lftpc.erl file, there are high-level and low-level functions depending on your needs. You can always drop down to lftpc:request/3,4,5,6 and lftpc:start_transfer/3 to do anything custom.