Provided by: erlang-manpages_20.2.2+dfsg-1ubuntu2_all 
NAME
ssh_sftp - SFTP client.
DESCRIPTION
This module implements an SSH FTP (SFTP) client. SFTP is a secure, encrypted file transfer
service available for SSH.
DATA TYPES
Type definitions that are used more than once in this module, or abstractions to indicate
the intended use of the data type, or both:
reason():
= atom() A description of the reason why an operation failed.
The value is formed from the sftp error codes in the protocol-level responses as
defined in draft-ietf-secsh-filexfer-13.txt section 9.1.
The codes are named as SSH_FX_* which are transformed into lowercase of the star-part.
E.g. the error code SSH_FX_NO_SUCH_FILE will cause the reason() to be no_such_file.
ssh_connection_ref() =:
opaque() - as returned by ssh:connect/3
timeout():
= infinity | integer() in milliseconds. Default infinity.
TIME-OUTS
If the request functions for the SFTP channel return {error, timeout}, no answer was
received from the server within the expected time.
The request may have reached the server and may have been performed. However, no answer
was received from the server within the expected time.
EXPORTS
apread(ChannelPid, Handle, Position, Len) -> {async, N} | {error, reason()}
Types:
ChannelPid = pid()
Handle = term()
Position = integer()
Len = integer()
N = term()
The apread/4 function reads from a specified position, combining the position/3 and
aread/3 functions.
apwrite(ChannelPid, Handle, Position, Data) -> {async, N} | {error, reason()}
Types:
ChannelPid = pid()
Handle = term()
Position = integer()
Len = integer()
Data = binary()
Timeout = timeout()
N = term()
The apwrite/4 function writes to a specified position, combining the position/3 and
awrite/3 functions.
aread(ChannelPid, Handle, Len) -> {async, N} | {error, reason()}
Types:
ChannelPid = pid()
Handle = term()
Position = integer()
Len = integer()
N = term()
Reads from an open file, without waiting for the result. If the handle is valid,
the function returns {async, N}, where N is a term guaranteed to be unique between
calls of aread. The actual data is sent as a message to the calling process. This
message has the form {async_reply, N, Result}, where Result is the result from the
read, either {ok, Data}, eof, or {error, reason()}.
awrite(ChannelPid, Handle, Data) -> {async, N} | {error, reason()}
Types:
ChannelPid = pid()
Handle = term()
Position = integer()
Len = integer()
Data = binary()
Timeout = timeout()
Writes to an open file, without waiting for the result. If the handle is valid, the
function returns {async, N}, where N is a term guaranteed to be unique between
calls of awrite. The result of the write operation is sent as a message to the
calling process. This message has the form {async_reply, N, Result}, where Result
is the result from the write, either ok, or {error, reason()}.
close(ChannelPid, Handle) ->
close(ChannelPid, Handle, Timeout) -> ok | {error, reason()}
Types:
ChannelPid = pid()
Handle = term()
Timeout = timeout()
Closes a handle to an open file or directory on the server.
delete(ChannelPid, Name) ->
delete(ChannelPid, Name, Timeout) -> ok | {error, reason()}
Types:
ChannelPid = pid()
Name = string()
Timeout = timeout()
Deletes the file specified by Name.
del_dir(ChannelPid, Name) ->
del_dir(ChannelPid, Name, Timeout) -> ok | {error, reason()}
Types:
ChannelPid = pid()
Name = string()
Timeout = timeout()
Deletes a directory specified by Name. The directory must be empty before it can be
successfully deleted.
list_dir(ChannelPid, Path) ->
list_dir(ChannelPid, Path, Timeout) -> {ok, Filenames} | {error, reason()}
Types:
ChannelPid = pid()
Path = string()
Filenames = [Filename]
Filename = string()
Timeout = timeout()
Lists the given directory on the server, returning the filenames as a list of
strings.
make_dir(ChannelPid, Name) ->
make_dir(ChannelPid, Name, Timeout) -> ok | {error, reason()}
Types:
ChannelPid = pid()
Name = string()
Timeout = timeout()
Creates a directory specified by Name. Name must be a full path to a new directory.
The directory can only be created in an existing directory.
make_symlink(ChannelPid, Name, Target) ->
make_symlink(ChannelPid, Name, Target, Timeout) -> ok | {error, reason()}
Types:
ChannelPid = pid()
Name = string()
Target = string()
Creates a symbolic link pointing to Target with the name Name.
open(ChannelPid, File, Mode) ->
open(ChannelPid, File, Mode, Timeout) -> {ok, Handle} | {error, reason()}
Types:
ChannelPid = pid()
File = string()
Mode = [Modeflag]
Modeflag = read | write | creat | trunc | append | binary
Timeout = timeout()
Handle = term()
Opens a file on the server and returns a handle, which can be used for reading or
writing.
opendir(ChannelPid, Path) ->
opendir(ChannelPid, Path, Timeout) -> {ok, Handle} | {error, reason()}
Types:
ChannelPid = pid()
Path = string()
Timeout = timeout()
Opens a handle to a directory on the server. The handle can be used for reading
directory contents.
open_tar(ChannelPid, Path, Mode) ->
open_tar(ChannelPid, Path, Mode, Timeout) -> {ok, Handle} | {error, reason()}
Types:
ChannelPid = pid()
Path = string()
Mode = [read] | [write] | [read,EncryptOpt] | [write,DecryptOpt]
EncryptOpt = {crypto,{InitFun,EncryptFun,CloseFun}}
DecryptOpt = {crypto,{InitFun,DecryptFun}}
InitFun = (fun() -> {ok,CryptoState}) | (fun() -> {ok,CryptoState,ChunkSize})
CryptoState = any()
ChunkSize = undefined | pos_integer()
EncryptFun = (fun(PlainBin,CryptoState) -> EncryptResult)
EncryptResult = {ok,EncryptedBin,CryptoState} |
{ok,EncryptedBin,CryptoState,ChunkSize}
PlainBin = binary()
EncryptedBin = binary()
DecryptFun = (fun(EncryptedBin,CryptoState) -> DecryptResult)
DecryptResult = {ok,PlainBin,CryptoState} | {ok,PlainBin,CryptoState,ChunkSize}
CloseFun = (fun(PlainBin,CryptoState) -> {ok,EncryptedBin})
Timeout = timeout()
Opens a handle to a tar file on the server, associated with ChannelPid. The handle
can be used for remote tar creation and extraction, as defined by the
erl_tar:init/3 function.
For code exampel see Section SFTP Client with TAR Compression and Encryption in the
ssh Users Guide.
The crypto mode option is applied to the generated stream of bytes prior to sending
them to the SFTP server. This is intended for encryption but can be used for other
purposes.
The InitFun is applied once prior to any other crypto operation. The returned
CryptoState is then folded into repeated applications of the EncryptFun or
DecryptFun. The binary returned from those funs are sent further to the remote SFTP
server. Finally, if doing encryption, the CloseFun is applied to the last piece of
data. The CloseFun is responsible for padding (if needed) and encryption of that
last piece.
The ChunkSize defines the size of the PlainBins that EncodeFun is applied to. If
the ChunkSize is undefined, the size of the PlainBins varies, because this is
intended for stream crypto, whereas a fixed ChunkSize is intended for block crypto.
ChunkSizes can be changed in the return from the EncryptFun or DecryptFun. The
value can be changed between pos_integer() and undefined.
position(ChannelPid, Handle, Location) ->
position(ChannelPid, Handle, Location, Timeout) -> {ok, NewPosition | {error, reason()}
Types:
ChannelPid = pid()
Handle = term()
Location = Offset | {bof, Offset} | {cur, Offset} | {eof, Offset} | bof | cur |
eof
Offset = integer()
Timeout = timeout()
NewPosition = integer()
Sets the file position of the file referenced by Handle. Returns {ok, NewPosition}
(as an absolute offset) if successful, otherwise {error, reason()}. Location is one
of the following:
Offset:
The same as {bof, Offset}.
{bof, Offset}:
Absolute offset.
{cur, Offset}:
Offset from the current position.
{eof, Offset}:
Offset from the end of file.
bof | cur | eof:
The same as eariler with Offset 0, that is, {bof, 0} | {cur, 0} | {eof, 0}.
pread(ChannelPid, Handle, Position, Len) ->
pread(ChannelPid, Handle, Position, Len, Timeout) -> {ok, Data} | eof | {error, reason()}
Types:
ChannelPid = pid()
Handle = term()
Position = integer()
Len = integer()
Timeout = timeout()
Data = string() | binary()
The pread/3,4 function reads from a specified position, combining the position/3
and read/3,4 functions.
pwrite(ChannelPid, Handle, Position, Data) -> ok
pwrite(ChannelPid, Handle, Position, Data, Timeout) -> ok | {error, reason()}
Types:
ChannelPid = pid()
Handle = term()
Position = integer()
Data = iolist()
Timeout = timeout()
The pwrite/3,4 function writes to a specified position, combining the position/3
and write/3,4 functions.
read(ChannelPid, Handle, Len) ->
read(ChannelPid, Handle, Len, Timeout) -> {ok, Data} | eof | {error, reason()}
Types:
ChannelPid = pid()
Handle = term()
Position = integer()
Len = integer()
Timeout = timeout()
Data = string() | binary()
Reads Len bytes from the file referenced by Handle. Returns {ok, Data}, eof, or
{error, reason()}. If the file is opened with binary, Data is a binary, otherwise
it is a string.
If the file is read past eof, only the remaining bytes are read and returned. If no
bytes are read, eof is returned.
read_file(ChannelPid, File) ->
read_file(ChannelPid, File, Timeout) -> {ok, Data} | {error, reason()}
Types:
ChannelPid = pid()
File = string()
Data = binary()
Timeout = timeout()
Reads a file from the server, and returns the data in a binary.
read_file_info(ChannelPid, Name) ->
read_file_info(ChannelPid, Name, Timeout) -> {ok, FileInfo} | {error, reason()}
Types:
ChannelPid = pid()
Name = string()
Handle = term()
Timeout = timeout()
FileInfo = record()
Returns a file_info record from the file specified by Name or Handle. See
file:read_file_info/2 for information about the record.
read_link(ChannelPid, Name) ->
read_link(ChannelPid, Name, Timeout) -> {ok, Target} | {error, reason()}
Types:
ChannelPid = pid()
Name = string()
Target = string()
Reads the link target from the symbolic link specified by name.
read_link_info(ChannelPid, Name) -> {ok, FileInfo} | {error, reason()}
read_link_info(ChannelPid, Name, Timeout) -> {ok, FileInfo} | {error, reason()}
Types:
ChannelPid = pid()
Name = string()
Handle = term()
Timeout = timeout()
FileInfo = record()
Returns a file_info record from the symbolic link specified by Name or Handle. See
file:read_link_info/2 for information about the record.
rename(ChannelPid, OldName, NewName) ->
rename(ChannelPid, OldName, NewName, Timeout) -> ok | {error, reason()}
Types:
ChannelPid = pid()
OldName = string()
NewName = string()
Timeout = timeout()
Renames a file named OldName and gives it the name NewName.
start_channel(ConnectionRef) ->
start_channel(ConnectionRef, Options) -> {ok, Pid} | {error, reason()|term()}
start_channel(Host, Options) ->
start_channel(Host, Port, Options) -> {ok, Pid, ConnectionRef} | {error, reason()|term()}
start_channel(TcpSocket) ->
start_channel(TcpSocket, Options) -> {ok, Pid, ConnectionRef} | {error, reason()|term()}
Types:
Host = string()
ConnectionRef = ssh_connection_ref()
Port = integer()
TcpSocket = port()
The socket is supposed to be from gen_tcp:connect or gen_tcp:accept with
option {active,false}
Options = [{Option, Value}]
If no connection reference is provided, a connection is set up, and the new
connection is returned. An SSH channel process is started to handle the
communication with the SFTP server. The returned pid for this process is to be used
as input to all other API functions in this module.
Options:
{timeout, timeout()}:
There are two ways to set a timeout for the underlying ssh connection:
* If the connection timeout option connect_timeout is set, that value is used
also for the negotiation timeout and this option (timeout) is ignored.
* Otherwise, this option (timeout) is used as the negotiation timeout only and
there is no connection timeout set
The value defaults to infinity.
{sftp_vsn, integer()}:
Desired SFTP protocol version. The actual version is the minimum of the desired
version and the maximum supported versions by the SFTP server.
All other options are directly passed to ssh:connect/3 or ignored if a connection
is already provided.
stop_channel(ChannelPid) -> ok
Types:
ChannelPid = pid()
Stops an SFTP channel. Does not close the SSH connection. Use ssh:close/1 to close
it.
write(ChannelPid, Handle, Data) ->
write(ChannelPid, Handle, Data, Timeout) -> ok | {error, reason()}
Types:
ChannelPid = pid()
Handle = term()
Position = integer()
Data = iolist()
Timeout = timeout()
Writes data to the file referenced by Handle. The file is to be opened with write
or append flag. Returns ok if successful or {error, reason()} otherwise.
write_file(ChannelPid, File, Iolist) ->
write_file(ChannelPid, File, Iolist, Timeout) -> ok | {error, reason()}
Types:
ChannelPid = pid()
File = string()
Iolist = iolist()
Timeout = timeout()
Writes a file to the server. The file is created if it does not exist but
overwritten if it exists.
write_file_info(ChannelPid, Name, Info) ->
write_file_info(ChannelPid, Name, Info, Timeout) -> ok | {error, reason()}
Types:
ChannelPid = pid()
Name = string()
Info = record()
Timeout = timeout()
Writes file information from a file_info record to the file specified by Name. See
file:write_file_info/[2,3] for information about the record.