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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, 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) ->
Types:
ChannelPid = pid()
Handle = term()
Timeout = timeout()
Closes a handle to an open file or directory on the server.
delete(ChannelPid, Name) ->
Types:
ChannelPid = pid()
Name = string()
Timeout = timeout()
Deletes the file specified by Name.
del_dir(ChannelPid, Name) ->
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) ->
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) ->
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) ->
Types:
ChannelPid = pid()
Name = string()
Target = string()
Creates a symbolic link pointing to Target with the name
Name.
open(ChannelPid, File, Mode) ->
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) ->
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) ->
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) ->
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:
pread(ChannelPid, Handle, Position, Len) ->
- 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}.
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
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) ->
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) ->
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) ->
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) ->
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()}
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) ->
Types:
ChannelPid = pid()
OldName = string()
NewName = string()
Timeout = timeout()
Renames a file named OldName and gives it the name NewName.
start_channel(ConnectionRef) ->
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:
All other options are directly passed to ssh:connect/3 or ignored if a
connection is already provided.
stop_channel(ChannelPid) -> ok
- {timeout, timeout()}:
- The time-out is passed to the ssh_channel start function, and 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.
Types:
ChannelPid = pid()
Stops an SFTP channel. Does not close the SSH connection. Use ssh:close/1
to close it.
write(ChannelPid, Handle, Data) ->
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) ->
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) ->
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.
ssh 4.4 | Ericsson AB |