ssh_sftp(3erl) Erlang Module Definition ssh_sftp(3erl)
NAME
ssh_sftp - SFTP client.
DESCRIPTION
This module implements an SSH FTP (SFTP) client. SFTP is a secure, en-
crypted file transfer service available for SSH.
DATA TYPES
sftp_option() =
{timeout, timeout()} |
{sftp_vsn, integer() >= 1} |
{window_size, integer() >= 1} |
{packet_size, integer() >= 1}
Error cause
reason() = atom() | string() | tuple()
A description of the reason why an operation failed.
The atom() value is formed from the sftp error codes in the pro-
tocol-level responses as defined in draft-ietf-secsh-filexfer-13
section 9.1. The codes are named as SSH_FX_* which are trans-
formed 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.
The string() reason is the error information from the server in
case of an exit-signal. If that information is empty, the reason
is the exit signal name.
The tuple() reason are other errors like for example {exit_sta-
tus,1}.
Crypto operations for open_tar
tar_crypto_spec() = encrypt_spec() | decrypt_spec()
encrypt_spec() = {init_fun(), crypto_fun(), final_fun()}
decrypt_spec() = {init_fun(), crypto_fun()}
Specifies the encryption or decryption applied to tar files when
using open_tar/3 or open_tar/4.
The encryption or decryption is applied to the generated stream
of bytes prior to sending the resulting stream to the SFTP
server.
For code examples see Section Example with encryption in the ssh
Users Guide.
init_fun() =
fun(() -> {ok, crypto_state()}) |
fun(() -> {ok, crypto_state(), chunk_size()})
chunk_size() = undefined | integer() >= 1
crypto_state() = any()
The init_fun() in the tar_crypto_spec is applied once prior to
any other crypto operation. The intention is that this function
initiates the encryption or decryption for example by calling
crypto:crypto_init/4 or similar. The crypto_state() is the state
such a function may return.
If the selected cipher needs to have the input data partioned
into blocks of a certain size, the init_fun() should return the
second form of return value with the chunk_size() set to the
block size. If the chunk_size() is undefined, the size of the
PlainBins varies, because this is intended for stream crypto,
whereas a fixed chunk_size() is intended for block crypto. A
chunk_size() can be changed in the return from the crypto_fun().
The value can be changed between pos_integer() and undefined.
crypto_fun() =
fun((TextIn :: binary(), crypto_state()) -> crypto_result())
crypto_result() =
{ok, TextOut :: binary(), crypto_state()} |
{ok, TextOut :: binary(), crypto_state(), chunk_size()}
The initial crypto_state() returned from the init_fun() is
folded into repeated applications of the crypto_fun() in the
tar_crypto_spec. The binary returned from that fun is sent to
the remote SFTP server and the new crypto_state() is used in the
next call of the crypto_fun().
If the crypto_fun() reurns a chunk_size(), that value is as
block size for further blocks in calls to crypto_fun().
final_fun() =
fun((FinalTextIn :: binary(), crypto_state()) ->
{ok, FinalTextOut :: binary()})
If doing encryption, the final_fun() in the tar_crypto_spec is
applied to the last piece of data. The final_fun() is responsi-
ble for padding (if needed) and encryption of that last piece.
EXPORTS
apread(ChannelPid, Handle, Position, Len) -> {async, N} | Error
Types:
ChannelPid = pid()
Handle = term()
Position = Len = integer()
Error = {error, reason()}
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
Types:
ChannelPid = pid()
Handle = term()
Position = integer()
Data = binary()
Error = {error, reason()}
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
Types:
ChannelPid = pid()
Handle = term()
Len = integer()
Error = {error, reason()}
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 re-
sult from the read, either {ok, Data}, eof, or {error, rea-
son()}.
awrite(ChannelPid, Handle, Data) -> {async, N} | Error
Types:
ChannelPid = pid()
Handle = term()
Data = binary()
Error = {error, reason()}
N = term()
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) -> ok | Error
close(ChannelPid, Handle, Timeout) -> ok | Error
Types:
ChannelPid = pid()
Handle = term()
Timeout = timeout()
Error = {error, reason()}
Closes a handle to an open file or directory on the server.
delete(ChannelPid, Name) -> ok | Error
delete(ChannelPid, Name, Timeout) -> ok | Error
Types:
ChannelPid = pid()
Name = string()
Timeout = timeout()
Error = {error, reason()}
Deletes the file specified by Name.
del_dir(ChannelPid, Name) -> ok | Error
del_dir(ChannelPid, Name, Timeout) -> ok | Error
Types:
ChannelPid = pid()
Name = string()
Timeout = timeout()
Error = {error, reason()}
Deletes a directory specified by Name. The directory must be
empty before it can be successfully deleted.
list_dir(ChannelPid, Path) -> {ok, FileNames} | Error
list_dir(ChannelPid, Path, Timeout) -> {ok, FileNames} | Error
Types:
ChannelPid = pid()
Path = string()
Timeout = timeout()
FileNames = [FileName]
FileName = string()
Error = {error, reason()}
Lists the given directory on the server, returning the filenames
as a list of strings.
make_dir(ChannelPid, Name) -> ok | Error
make_dir(ChannelPid, Name, Timeout) -> ok | Error
Types:
ChannelPid = pid()
Name = string()
Timeout = timeout()
Error = {error, reason()}
Creates a directory specified by Name. Name must be a full path
to a new directory. The directory can only be created in an ex-
isting directory.
make_symlink(ChannelPid, Name, Target) -> ok | Error
make_symlink(ChannelPid, Name, Target, Timeout) -> ok | Error
Types:
ChannelPid = pid()
Name = Target = string()
Timeout = timeout()
Error = {error, reason()}
Creates a symbolic link pointing to Target with the name Name.
open(ChannelPid, Name, Mode) -> {ok, Handle} | Error
open(ChannelPid, Name, Mode, Timeout) -> {ok, Handle} | Error
Types:
ChannelPid = pid()
Name = string()
Mode = [read | write | append | binary | raw]
Timeout = timeout()
Handle = term()
Error = {error, reason()}
Opens a file on the server and returns a handle, which can be
used for reading or writing.
opendir(ChannelPid, Path) -> {ok, Handle} | Error
opendir(ChannelPid, Path, Timeout) -> {ok, Handle} | Error
Types:
ChannelPid = pid()
Path = string()
Timeout = timeout()
Handle = term()
Error = {error, reason()}
Opens a handle to a directory on the server. The handle can be
used for reading directory contents.
open_tar(ChannelPid, Path, Mode) -> {ok, Handle} | Error
open_tar(ChannelPid, Path, Mode, Timeout) -> {ok, Handle} | Error
Types:
ChannelPid = pid()
Path = string()
Mode = [read | write | {crypto, tar_crypto_spec()}]
Timeout = timeout()
Handle = term()
Error = {error, reason()}
Opens a handle to a tar file on the server, associated with
ChannelPid. The handle can be used for remote tar creation and
extraction. The actual writing and reading is performed by calls
to erl_tar:add/3,4 and erl_tar:extract/2. Note: The
erl_tar:init/3 function should not be called, that one is called
by this open_tar function.
For code examples see Section SFTP Client with TAR Compression
in the ssh Users Guide.
The crypto mode option is explained in the data types section
above, see Crypto operations for open_tar. Encryption is assumed
if the Mode contains write, and decryption if the Mode contains
read.
position(ChannelPid, Handle, Location) ->
{ok, NewPosition} | Error
position(ChannelPid, Handle, Location, Timeout) ->
{ok, NewPosition} | Error
Types:
ChannelPid = pid()
Handle = term()
Location =
Offset |
{bof, Offset} |
{cur, Offset} |
{eof, Offset} |
bof | cur | eof
Timeout = timeout()
Offset = NewPosition = integer()
Error = {error, reason()}
Sets the file position of the file referenced by Handle. Returns
{ok, NewPosition} (as an absolute offset) if successful, other-
wise {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) ->
{ok, Data} | eof | Error
pread(ChannelPid, Handle, Position, Len, Timeout) ->
{ok, Data} | eof | Error
Types:
ChannelPid = pid()
Handle = term()
Position = Len = integer()
Timeout = timeout()
Data = string() | binary()
Error = {error, reason()}
The pread/3,4 function reads from a specified position, combin-
ing the position/3 and read/3,4 functions.
pwrite(ChannelPid, Handle, Position, Data) -> ok | Error
pwrite(ChannelPid, Handle, Position, Data, Timeout) -> ok | Error
Types:
ChannelPid = pid()
Handle = term()
Position = integer()
Data = iolist()
Timeout = timeout()
Error = {error, reason()}
The pwrite/3,4 function writes to a specified position, combin-
ing the position/3 and write/3,4 functions.
read(ChannelPid, Handle, Len) -> {ok, Data} | eof | Error
read(ChannelPid, Handle, Len, Timeout) -> {ok, Data} | eof | Error
Types:
ChannelPid = pid()
Handle = term()
Len = integer()
Timeout = timeout()
Data = string() | binary()
Error = {error, reason()}
Reads Len bytes from the file referenced by Handle. Returns {ok,
Data}, eof, or {error, reason()}. If the file is opened with bi-
nary, 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) -> {ok, Data} | Error
read_file(ChannelPid, File, Timeout) -> {ok, Data} | Error
Types:
ChannelPid = pid()
File = string()
Data = binary()
Timeout = timeout()
Error = {error, reason()}
Reads a file from the server, and returns the data in a binary.
read_file_info(ChannelPid, Name) -> {ok, FileInfo} | Error
read_file_info(ChannelPid, Name, Timeout) ->
{ok, FileInfo} | Error
Types:
ChannelPid = pid()
Name = string()
Timeout = timeout()
FileInfo = file:file_info()
Error = {error, reason()}
Returns a file_info record from the file system object specified
by Name or Handle. See file:read_file_info/2 for information
about the record.
Depending on the underlying OS:es links might be followed and
info on the final file, directory etc is returned. See
read_link_info/2 on how to get information on links instead.
read_link(ChannelPid, Name) -> {ok, Target} | Error
read_link(ChannelPid, Name, Timeout) -> {ok, Target} | Error
Types:
ChannelPid = pid()
Name = Target = string()
Timeout = timeout()
Error = {error, reason()}
Reads the link target from the symbolic link specified by name.
read_link_info(ChannelPid, Name) -> {ok, FileInfo} | Error
read_link_info(ChannelPid, Name, Timeout) ->
{ok, FileInfo} | Error
Types:
ChannelPid = pid()
Name = string()
FileInfo = file:file_info()
Timeout = timeout()
Error = {error, reason()}
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) -> ok | Error
rename(ChannelPid, OldName, NewName, Timeout) -> ok | Error
Types:
ChannelPid = pid()
OldName = NewName = string()
Timeout = timeout()
Error = {error, reason()}
Renames a file named OldName and gives it the name NewName.
start_channel(ConnectionRef) ->
start_channel(ConnectionRef, SftpOptions) -> {ok, ChannelPid} | Error
start_channel(Host) ->
start_channel(Host, Options) ->
start_channel(Host, Port, Options) ->
start_channel(TcpSocket) ->
start_channel(TcpSocket, Options) -> {ok, ChannelPid, ConnectionRef} |
Error
Types:
Host = ssh:host()
Port = inet:port_number()
TcpSocket = ssh:open_socket()
Options = [ sftp_option() | ssh:client_option() ]
SftpOptions = [ sftp_option() ]
ChannelPid = pid()
ConnectionRef = ssh:connection_ref()
Error = {error, reason()}
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 negotia-
tion 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 ig-
nored 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) -> ok | Error
write(ChannelPid, Handle, Data, Timeout) -> ok | Error
Types:
ChannelPid = pid()
Handle = term()
Data = iodata()
Timeout = timeout()
Error = {error, reason()}
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, Data) -> ok | Error
write_file(ChannelPid, File, Data, Timeout) -> ok | Error
Types:
ChannelPid = pid()
File = string()
Data = iodata()
Timeout = timeout()
Error = {error, reason()}
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, FileInfo) -> ok | Error
write_file_info(ChannelPid, Name, FileInfo, Timeout) -> ok | Error
Types:
ChannelPid = pid()
Name = string()
FileInfo = file:file_info()
Timeout = timeout()
Error = {error, reason()}
Writes file information from a file_info record to the file
specified by Name. See file:write_file_info/[2,3] for informa-
tion about the record.
Ericsson AB ssh 4.10 ssh_sftp(3erl)