account(Pid, Account) -> ok | {error, Reason}
Types
Sets the account for an operation, if needed.
ftp
A File Transfer Protocol client.
This module implements a client for file transfer according to a subset of the File Transfer Protocol (FTP), see RFC 959
.
The FTP client always tries to use passive FTP mode and only resort to active FTP mode if this fails. This default behavior can be changed by start option mode
.
An FTP client is always started as part of the ftp application and legacy start_service
function, is deprecated in OTP-24
For a simple example of an FTP session, see FTP 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 be stored as remote files (see send_bin/3
).
A set of functions is provided 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
. For receive, see recv_chunk_start/2
and recv_chunk/
).
The return values of the following functions depend 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 example, 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 a directory that exists but is empty.
The FTP client can be started and stopped dynamically in runtime by calling the ftp
application API ftp:open(Host, Options)
and ftp:close(Client)
.
The available configuration options are as follows:
Host = string() | ip_address()
Port = integer() > 0
Default is 0
which aliases to 21
or 990
when used with {tls_sec_method,ftps}
).
Mode = active | passive
Default is passive
.
Verbose = boolean()
Determines if the FTP communication is to be verbose or not.
Default is false
.
Debug = trace | debug | disable
Debugging using the dbg toolkit.
Default is disable
.
IpFamily = inet | inet6 | inet6fb4
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 = non_neg_integer()
Connection time-out.
Default is 60000
(milliseconds).
DTimeout = non_neg_integer() | infinity
Data connect time-out. The time the client waits for the server to connect to the data socket.
Default is infinity
.
Progress = ignore | {CBModule, CBFunction, InitProgress}
CBModule = atom()
, CBFunction = atom()
InitProgress = 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.
CBModule:CBFunction(InitProgress, File, {file_size, FileSize})
Every time a chunk of bytes is transferred the following call is made:
CBModule:CBFunction(UserProgressTerm, File, {transfer_size, TransferSize})
At the end of the file the following call is made to indicate the end of the transfer:
CBModule:CBFunction(UserProgressTerm, File, {transfer_size, 0})
The callback function is to be defined as follows:
CBModule:CBFunction(UserProgressTerm, File, Size) -> UserProgressTerm
CBModule = CBFunction = atom()
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.
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.
The following type definitions 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
- all restrictions are not always relevant to all functions
common_reason()
= econn | eclosed | term()
- some explanation of what went wrong
Sets the account for an operation, if needed.
Transfers the file LocalFile
to the remote server. If RemoteFile
is specified, the name of the remote file that the file is appended to is set to RemoteFile
, otherwise to LocalFile
. If the file does not exists, it is created.
Transfers the binary Bin
to the remote server and appends it to the file RemoteFile
. If the file does not exist, it is created.
Transfers the chunk Bin
to the remote server, which appends it to the file specified in the call to append_chunk_start/2
.
For some errors, for example, file system full, it is necessary to call append_chunk_end
to get the proper reason.
Starts the transfer of chunks for appending to the file File
at the remote server. If the file does not exist, it is created.
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.
Changes the working directory at the remote server to Dir
.
Ends an FTP session, created using function open
.
Deletes the file File
at the remote server.
Given an error return value {error, AtomReason}
, this function returns a readable string describing the error.
Changes the working directory to Dir
for the local client.
Returns the current working directory at the local client.
Returns a list of files in long format.
Pathname
can be a directory, a group of files, or a file. The Pathname
string can contain wildcards.
ls/1
implies the current remote directory of the user.
The format of Listing
depends on the operating system. On UNIX, it is typically produced from the output of the ls -l
shell command.
Creates the directory Dir
at the remote server.
Returns a list of files in short format.
Pathname
can be a directory, a group of files, or a file. The Pathname
string can contain wildcards.
nlist/1
implies the current remote directory of the user.
The format of Listing
is a stream of filenames where each filename is separated by <CRLF> or <NL>. Contrary to function ls
, the purpose of nlist
is to enable a program to process filename information automatically.
Starts a FTP client process and opens a session with the FTP server at Host
.
If option {tls, tls_options()}
is present, the FTP session is transported over tls
(ftps
, see RFC 4217
). The list tls_options()
can be empty. The function ssl:connect/3
is used for securing both the control connection and the data sessions.
The suboption {tls_sec_method, tls_sec_method()}
(defaults to ftpes
) 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.
The option {tls_ctrl_session_reuse, boolean()}
(defaults to false
) 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
).
The options sock_ctrl
, sock_data_act
and sock_data_pass
passes options down to the underlying transport layer (tcp). The default value for sock_ctrl
is []
. Both sock_data_act
and sock_data_pass
uses the value of sock_ctrl
as default value.
A session opened in this way is closed using function close
.
Returns the current working directory at the remote server.
Transfers the file RemoteFile
from the remote server to the file system of the local client. If LocalFile
is specified, the local file will be LocalFile
, otherwise RemoteFile
.
If the file write fails (for example, enospc
), the command is aborted and {error, file_write_error_reason()}
is returned. However, the file is not removed.
Transfers the file RemoteFile
from the remote server and receives it as a binary.
Starts transfer of the file RemoteFile
from the remote server.
Receives a chunk of the remote file (RemoteFile
of recv_chunk_start
). The return values have the following meaning:
ok
= the transfer is complete.{ok, Bin}
= just another chunk of the file.{error, Reason}
= transfer failed.Renames Old
to New
at the remote server.
Removes directory Dir
at the remote server.
Transfers the file LocalFile
to the remote server. If RemoteFile
is specified, the name of the remote file is set to RemoteFile
, otherwise to LocalFile
.
Transfers the binary Bin
into the file RemoteFile
at the remote server.
Transfers the chunk Bin
to the remote server, which writes it into the file specified in the call to send_chunk_start/2
.
For some errors, for example, file system full, it is necessary to to call send_chunk_end
to get the proper reason.
Starts transfer of chunks into the file File
at the remote server.
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.
Dynamically starts an FTP
session after the ftp
application has been started.
As long as the ftp
application is operational, the FTP sessions are supervised and can be soft code upgraded.
Stops a started FTP session.
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 default according to RFC 959
.
Performs login of User
with Password
.
Performs login of User
with Password
to the account specified by Account
.
The telnet end of line characters, from the FTP protocol definition, CRLF, for example, "\\r\\n" has been removed.
Sends an arbitrary FTP command and returns verbatim a list of the lines sent back by the FTP server. This function is intended to give application accesses to FTP commands that are server-specific or that cannot be provided by this FTP client.
FTP commands requiring a data connection cannot be successfully issued with this function.
The possible error reasons and the corresponding diagnostic strings returned by formaterror/1
are as follows:
echunk
Synchronization error during chunk sending according to one of the following:
send_chunk/2
or send_chunk_end/1
before a call to send_chunk_start/2
.send_chunk_end/1
.eclosed
The session is closed.
econn
Connection to the remote server is prematurely closed.
ehost
Host is not found, FTP server is not found, or connection is rejected by FTP server.
elogin
User is not logged in.
enotbinary
Term is not a binary.
epath
No such file or directory, or directory already exists, or permission denied.
etype
No such type.
euser
Invalid username or password.
etnospc
Insufficient storage space in system [452].
epnospc
Exceeded storage allocation (for current directory or dataset) [552].
efnamena
Filename not allowed [553].
file(3)
filename(3)
and J. Postel and J. Reynolds: File Transfer Protocol (RFC 959
).
© 2010–2022 Ericsson AB
Licensed under the Apache License, Version 2.0.