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The ftp module implements a client for file transfer
according to a subset of the File Transfer Protocol (see RFC 959). Starting from inets version 4.4.1 the ftp client
will always try to use passive ftp mode and only resort to active
ftp mode if this fails. There is a mode option for open/[1,2,3]
where this default behavior may be changed. Also the mode option
replaces the API function force_active/1 that now has become
deprecated. (force_active/1 is removed from the documentation but
is still available in the code for now.)
For a simple example of an ftp session see Inets User's Guide.
In addition to the ordinary functions for receiving and sending
files (see recv/2, recv/3, send/2 and
send/3) there are functions for receiving remote files as
binaries (see recv_bin/2) and for sending binaries to to be
stored as remote files (see send_bin/3).
There is also a set of functions for sending and receiving
contiguous parts of a file to be stored in a remote file (for send
see send_chunk_start/2, send_chunk/2 and
send_chunk_end/1 and for receive see
recv_chunk_start/2 and recv_chunk/).
The particular return values of the functions below depend very
much on the implementation of the FTP server at the remote host. In
particular the results from ls and nlist varies. Often
real errors are not reported as errors by ls, even if for
instance a file or directory does not exist. nlist is usually
more strict, but some implementations have the peculiar behaviour of
responding with an error, if the request is a listing of the
contents of directory which exists but is empty.
Here follows type definitions that are used by more than one function in the FTP client API.
pid() - identifier of an ftp connection.
string() = list of ASCII characters
shortage_reason() = etnospc | epnospc
restriction_reason() = epath | efnamena | elogin | enotbinary
- note not all restrictions may always relevant to all functions
common_reason() = econn | eclosed | term() - some kind of
explanation of what went wrong
account(Pid, Account) -> ok | {error, Reason}
Types:
Pid = pid()
Account = string()
Reason = eacct | common_reason()
If an account is needed for an operation set the account with this operation.
append(Pid, LocalFile [, RemoteFile]) -> ok | {error,
Reason}
Types:
Pid = pid()
LocalFile = RemoteFile = string()
Reason = epath | elogin | etnospc | epnospc | efnamena | common_reason
Transfers the file LocalFile to the remote server. If
RemoteFile is specified, the name of the remote file that the
file will be appended to is set to RemoteFile; otherwise
the name is set to LocalFile If the file does not exists the
file will be created.
append_bin(Pid, Bin, RemoteFile) -> ok | {error, Reason}
Types:
Pid = pid()
Bin = binary()()
RemoteFile = string()
Reason = restriction_reason()| shortage_reason() |
common_reason()
Transfers the binary Bin to the remote server and append
it to the file RemoteFile. If the file does not exists it
will be created.
append_chunk(Pid, Bin) -> ok | {error, Reason}
Types:
Pid = pid()
Bin = binary()
Reason = echunk | restriction_reason() | common_reason()
Transfer the chunk Bin to the remote server, which
append it into the file specified in the call to
append_chunk_start/2.
Note that for some errors, e.g. file system full, it is
neccessery to to call append_chunk_end to get the
proper reason.
append_chunk_start(Pid, File) -> ok | {error, Reason}
Types:
Pid = pid()
File = string()
Reason = restriction_reason() | common_reason()
Start the transfer of chunks for appending to the file
File at the remote server. If the file does not exists
it will be created.
append_chunk_end(Pid) -> ok | {error, Reason}
Types:
Pid = pid()
Reason = echunk | restriction_reason() | shortage_reason()
Stops transfer of chunks for appending to the remote server.
The file at the remote server, specified in the call to
append_chunk_start/2 is closed by the server.
cd(Pid, Dir) -> ok | {error, Reason}
Types:
Pid = pid()
Dir = string()
Reason = restriction_reason() | common_reason()
Changes the working directory at the remote server to Dir.
Types:
Pid = pid()
Ends the ftp session.
delete(Pid, File) -> ok | {error, Reason}
Types:
Pid = pid()
File = string()
Reason = restriction_reason() | common_reason()
Deletes the file File at the remote server.
Types:
Tag = {error, atom()} | atom()
Given an error return value {error, AtomReason},
this function returns a readable string describing the error.
lcd(Pid, Dir) -> ok | {error, Reason}
Types:
Pid = pid()
Dir = string()
Reason = restriction_reason()
Changes the working directory to Dir for the local client.
Types:
Pid = pid()
Returns the current working directory at the local client.
ls(Pid [, Dir]) -> {ok, Listing} | {error, Reason}
Types:
Pid = pid()
Dir = string()
Listing = string()
Reason = restriction_reason() | common_reason()
Returns a listing of the contents of the remote current directory
(ls/1) or the specified directory (ls/2). The format
of Listing is operating system dependent (on UNIX it is
typically produced from the output of the ls -l shell command).
mkdir(Pid, Dir) -> ok | {error, Reason}
Types:
Pid = pid()
Dir = string()
Reason = restriction_reason() | common_reason()
Creates the directory Dir at the remote server.
nlist(Pid [, Dir]) -> {ok, Listing} | {error, Reason}
Types:
Pid = pid()
Dir = string()
Listing = string()
Reason = restriction_reason() | common_reason()
Returns a listing of the contents of the remote current directory
(nlist/1) or the specified directory
(nlist/2). The format of Listing is a stream of
file names, where each name is separated by <CRLF> or
<NL>. Contrary to the ls function, the purpose of
nlist is to make it possible for a program to
automatically process file name information.
open(Host [, Port] [, Flags]) -> {ok, Pid} | {error, Reason}
open({option_list, Option_list}) -> {ok, Pid} | {error, Reason}
Types:
Host = string() | ip_address()
ip_address() = {byte(), byte(), byte(), byte()}
{byte(), byte(), byte(), byte(), byte(), byte(), byte(), byte()}
byte() = 0 | 1 | ... | 255
Port = integer()
Flags = [Flag]
Flag = verbose | debug | ip_v6_disabled
Pid = pid()
Reason = ehost
Option_list = [Options]
Options = {host, Host} | {port, Port} | {mode, Mode} |
{flags, Flags} | {timeout, Timeout} | {progress, ProgressOption}
Mode = active | passive
Timeout = integer()
ProgressOption = ignore | {CBModule, CBFunction,
InitProgress}
CallBackModule = atom()
CallBackFunction = atom()
InitProgress = term()
Opens a session with the ftp server at Host. The argument
Host is either the name of the host, its IP address in
dotted decimal notation (e.g. "150.236.14.136"), or a tuple
of arity 4 (ipv4) or 8 (ipv6) (ex: {150, 236, 14, 136}).
If Port is supplied, a connection is attempted using this
port number instead of the default (21).
Default value for Mode is passive.
If the atom verbose is included in Flags,
response messages from the remote server will be written
to standard output.
The progress option is intended to be used by applications that want create some type of progress report such as a progress bar in a GUI. The default value for the progress option is ignore e.i. the option is not used. When the progress option is specified the following will happen when ftp:send/[3,4] or ftp:recv/[3,4] are called.
CBModule:CBFunction(InitProgress, File, {file_size, FileSize})
CBModule:CBFunction(UserProgressTerm, File, {transfer_size, TransferSize})
CBModule:CBFunction(UserProgressTerm, File, {transfer_size, 0})
The callback function should be defined as
CBModule:CBFunction(UserProgressTerm, File, Size) -> UserProgressTerm
CBModule = CBFunction = atom()
UserProgressTerm = term()
File = string()
Size = {transfer_size, integer()} | {file_size, integer()} | {file_size, unknown}
Alas for remote files it is not possible for ftp to
determine the file size in a platform independent way. In
this case the size will be unknown and it is
left to the application to find out the size.
 |
The callback is made by a middleman process, hence the file transfer will not be affected by the code in the progress callback function. If the callback should crash this will be detected by the ftp connection process that will print an info-report and then go one 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 ASCCI-mode.
The current local working directory (cf. lpwd/1) is
set to the value reported by file:get_cwd/1. the wanted
local directory.
The timeout value is default set to 60000 milliseconds.
The return value Pid is used as a reference to the
newly created ftp client in all other functions, and they should
be called by the process that created the connection. The ftp
client process monitors the process that created it and
will terminate if that process terminates.
pwd(Pid) -> {ok, Dir} | {error, Reason}
Types:
Pid = pid()
Reason = restriction_reason() | common_reason()
Returns the current working directory at the remote server.
recv(Pid, RemoteFile [, LocalFile]) -> ok |
{error, Reason}
Types:
Pid = pid()
RemoteFile = LocalFile = string()
Reason = restriction_reason() | common_reason()
| file_write_error_reason()
file_write_error_reason() = see file:write/2
Transfer the file RemoteFile from the remote server
to the the file system of the local client. If
LocalFile is specified, the local file will be
LocalFile; otherwise it will be
RemoteFile.
If the file write failes
(e.g. enospc), then the command is aborted and {error,
file_write_error_reason()} is returned. The file is
however not removed.
recv_bin(Pid, RemoteFile) -> {ok, Bin} | {error, Reason}
Types:
Pid = pid()
Bin = binary()
RemoteFile = string()
Reason = restriction_reason() | common_reason()
Transfers the file RemoteFile from the remote server and
receives it as a binary.
recv_chunk_start(Pid, RemoteFile) -> ok | {error, Reason}
Types:
Pid = pid()
RemoteFile = string()
Reason = restriction_reason() | common_reason()
Start transfer of the file RemoteFile from the
remote server.
recv_chunk(Pid) -> ok | {ok, Bin} | {error, Reason}
Types:
Pid = pid()
Bin = binary()
Reason = restriction_reason() | common_reason()
Receive a chunk of the remote file (RemoteFile of
recv_chunk_start). The return values has the following
meaning:
ok the transfer is complete.
{ok, Bin} just another chunk of the file.
{error, Reason} transfer failed.
rename(Pid, Old, New) -> ok | {error, Reason}
Types:
Pid = pid()
CurrFile = NewFile = string()
Reason = restriction_reason() | common_reason()
Renames Old to New at the remote server.
rmdir(Pid, Dir) -> ok | {error, Reason}
Types:
Pid = pid()
Dir = string()
Reason = restriction_reason() | common_reason()
Removes directory Dir at the remote server.
send(Pid, LocalFile [, RemoteFile]) -> ok |
{error, Reason}
Types:
Pid = pid()
LocalFile = RemoteFile = string()
Reason = restriction_reason() | common_reason() |
shortage_reason()
Transfers the file LocalFile to the remote server. If
RemoteFile is specified, the name of the remote file is set
to RemoteFile; otherwise the name is set to LocalFile.
send_bin(Pid, Bin, RemoteFile) -> ok | {error, Reason}
Types:
Pid = pid()
Bin = binary()()
RemoteFile = string()
Reason = restriction_reason() | common_reason() |
shortage_reason()
Transfers the binary Bin into the file RemoteFile
at the remote server.
send_chunk(Pid, Bin) -> ok | {error, Reason}
Types:
Pid = pid()
Bin = binary()
Reason = echunk | restriction_reason() | common_reason()
Transfer the chunk Bin to the remote server, which
writes it into the file specified in the call to
send_chunk_start/2.
Note that for some errors, e.g. file system full, it is
neccessery to to call send_chunk_end to get the
proper reason.
send_chunk_start(Pid, File) -> ok | {error, Reason}
Types:
Pid = pid()
File = string()
Reason = restriction_reason() | common_reason()
Start transfer of chunks into the file File at the
remote server.
send_chunk_end(Pid) -> ok | {error, Reason}
Types:
Pid = pid()
Reason = restriction_reason() | common_reason() |
shortage_reason()
Stops transfer of chunks to the remote server. The file at the
remote server, specified in the call to send_chunk_start/2
is closed by the server.
type(Pid, Type) -> ok | {error, Reason}
Types:
Pid = pid()
Type = ascii | binary
Reason = etype | restriction_reason() | common_reason()
Sets the file transfer type to ascii or binary. When
an ftp session is opened, the default transfer type of the
server is used, most often ascii, which is the default
according to RFC 959.
user(Pid, User, Password) -> ok | {error, Reason}
Types:
Pid = pid()
User = Password = string()
Reason = euser | common_reason()
Performs login of User with Password.
user(Pid, User, Password,Account) -> ok | {error, Reason}
Types:
Pid = pid()
User = Password = string()
Reason = euser | common_reason()
Performs login of User with Passwordto the acccount
specified by Account .
quote(Pid, Command) -> [FTPLine]
Types:
Pid = pid()
Command = string()
FTPLine = string() - Note the telnet end of line characters, from
the ftp protocol definition, CRLF e.g. "\r\n" has been removed.
Sends an arbitrary FTP command and returns verbatimly a list of the lines sent back by the FTP server. This functions is intended to give an application accesses to FTP commands that are server specific or that may not be provided by this FTP client.
|
FTP commands that require a data connection can not be successfully issued with this function. |
The possible error reasons and the corresponding diagnostic strings
returned by formaterror/1 are as follows:
echunk
send_chunk/2 or
send_chunk_end/1, before a call to
send_chunk_start/2; or a call has been made to another
transfer function during chunk sending, i.e. before a call
to send_chunk_end/1.
eclosed
econn
ehost
elogin
enotbinary
epath
etype
euser
etnospc
epnospc
efnamena
file, filename, J. Postel and J. Reynolds: File Transfer Protocol (RFC 959).