-spec account(Client :: client(), Acc :: string()) -> ok | {error, Reason :: term()}.

Sets the account for an operation, if needed.

-spec close(Client :: client()) -> ok.

Ends an FTP session, created using function open.

-spec open(Host :: inet:hostname() | inet:ip_address()) ->
              {ok, Client :: client()} | {error, Reason :: term()}.

Equivalent to open/2.

-spec open(Host :: string() | inet:ip_address(), Opts) ->
              {ok, Client :: client()} | {error, Reason :: term()}
              when
                  Opts :: [Opt],
                  Opt :: StartOption | OpenOption,
                  StartOption :: {verbose, Verbose} | {debug, Debug},
                  Verbose :: boolean(),
                  Debug :: disable | debug | trace,
                  OpenOption ::
                      {ipfamily, IpFamily} |
                      {port, Port :: port()} |
                      {mode, Mode} |
                      {tls, TLSOptions :: [ssl:tls_option()]} |
                      {tls_sec_method, TLSSecMethod :: ftps | ftpes} |
                      {tls_ctrl_session_reuse, TLSSessionReuse :: boolean()} |
                      {timeout, Timeout :: timeout()} |
                      {dtimeout, DTimeout :: timeout()} |
                      {progress, Progress} |
                      {sock_ctrl, SocketCtrls} |
                      {sock_data_act, [SocketControl]} |
                      {sock_data_pass, [SocketControl]},
                  SocketCtrls :: [SocketControl],
                  IpFamily :: inet | inet6 | inet6fb4,
                  Mode :: active | passive,
                  Module :: atom(),
                  Function :: atom(),
                  InitialData :: term(),
                  Progress :: ignore | {Module, Function, InitialData},
                  SocketControl :: gen_tcp:option().

Starts a FTP client process and opens a session with the FTP server at Host.

A session opened in this way is closed using function close/1.

The available configuration options are as follows:

• {host, Host} - Host = string() | ip_address()

• {port, Port} - Default is 0 which aliases to 21 or 990 when used with {tls_sec_method,ftps}).

• {mode, Mode} - Default is passive.

• {verbose, Verbose} - Determines if the FTP communication is to be verbose or not.

  Default is false.

• {debug, Debug} - Debugging using the dbg toolkit.

  Default is disable.

• {ipfamily, IpFamily} - With inet6fb4 the client behaves as before, that is, tries to use IPv6, and only if that does not work it uses IPv4).

  Default is inet (IPv4).

• {timeout, Timeout} - Connection time-out.

  Default is 60000 (milliseconds).

• {dtimeout, DTimeout} - Data connect time-out. The time the client waits for the server to connect to the data socket.

  Default is infinity.

• {tls, TLSOptions} - The FTP session is transported over tls (ftps, see RFC 4217). The list TLSOptions can be empty. The function ssl:connect/3 is used for securing both the control connection and the data sessions.

• {tls_sec_method, TLSSecMethod} - When set to ftps will connect immediately with SSL instead of upgrading with STARTTLS. This suboption is ignored unless the suboption tls is also set.

  Default is ftpes

• {tls_ctrl_session_reuse, boolean()} - When set to true the client will re-use the TLS session from the control channel on the data channel as enforced by many FTP servers as (proposed and implemented first by vsftpd).

  Default is false.

• {sock_ctrl, SocketCtrls :: [SocketControl :: gen_tcp:option()]} - Passes options from SocketCtrls down to the underlying transport layer (tcp).

  gen_tcp:option/0 except for ipv6_v6only, active, packet, mode, packet_size and header.

  Default value is SocketCtrls = [].

• {sock_data_act, [SocketControl]} - Passes options from [SocketControl] down to the underlying transport layer (tcp).

  sock_data_act uses the value of sock_ctrl as default value.

• {sock_data_pass, [SocketControl]} - Passes options from [SocketControl] down to the underlying transport layer (tcp).

  sock_data_pass uses the value of sock_ctrl as default value.

• {progress, Progress} - Progress = ignore | {Module, Function, InitialData}

  Module = atom(), Function = atom()

  InitialData = term()

  Default is ignore.

  Option progress is intended to be used by applications that want to create some type of progress report, such as a progress bar in a GUI. Default for the progress option is ignore, that is, the option is not used. When the progress option is specified, the following happens when ftp:send/[3,4] or ftp:recv/[3,4] are called:

  • Before a file is transferred, the following call is made to indicate the start of the file transfer and how large the file is. The return value of the callback function is to be a new value for the UserProgressTerm that will be used as input the next time the callback function is called.

    Module:Function(InitialData, File, {file_size, FileSize})

  • Every time a chunk of bytes is transferred the following call is made:

    Module:Function(UserProgressTerm, File, {transfer_size, TransferSize})

  • At the end of the file the following call is made to indicate the end of the transfer:

    Module:Function(UserProgressTerm, File, {transfer_size, 0})

  The callback function is to be defined as follows:

  Module:Function(UserProgressTerm, File, Size) -> UserProgressTerm

  UserProgressTerm = term()

  File = string()

  Size = {transfer_size, integer()} | {file_size, integer()} | {file_size, unknown}

  For remote files, ftp cannot determine the file size in a platform independent way. In this case the size becomes unknown and it is left to the application to determine the size.

  Note

  The callback is made by a middleman process, hence the file transfer is not affected by the code in the progress callback function. If the callback crashes, this is detected by the FTP connection process, which then prints an info-report and goes on as if the progress option was set to ignore.

  The file transfer type is set to the default of the FTP server when the session is opened. This is usually ASCII mode.

  The current local working directory (compare lpwd/1) is set to the value reported by file:get_cwd/1, the wanted local directory.

  The return value Pid is used as a reference to the newly created FTP client in all other functions, and they are to be called by the process that created the connection. The FTP client process monitors the process that created it and terminates if that process terminates.

-spec user(Pid :: pid(), User :: string(), Pass :: string()) -> ok | {error, Reason :: term()}.

Performs login of User with Pass.

-spec user(Pid :: pid(), User :: string(), Pass :: string(), Account :: string()) ->
              ok | {error, Reason :: term()}.

Performs login of User with Pass to the account specified by Account.