View Source ssh_sftp (ssh v5.2)
SFTP client.
This module implements an SSH FTP (SFTP) client. SFTP is a secure, encrypted file transfer service available for SSH.
Summary
Types: Error cause
A description of the reason why an operation failed.
Types: Crypto operations for open_tar
The initial crypto_state/0 returned from the init_fun/0 is folded into
repeated applications of the crypto_fun/0 in the
tar_crypto_spec. The binary returned from that fun is
sent to the remote SFTP server and the new crypto_state/0 is used in the
next call of the crypto_fun/0.
The init_fun/0 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/0 is the state such a
function may return.
Specifies the encryption or decryption applied to tar files when using
open_tar/3 or open_tar/4.
If doing encryption, the final_fun/0 in the
tar_crypto_spec is applied to the last piece of data.
The final_fun/0 is responsible for padding (if needed) and encryption of
that last piece.
Functions
The apread/4 function reads from a specified position, combining
the position/3 and aread/3 functions.
The apwrite/4 function writes to a specified position,
combining the position/3 and awrite/3 functions.
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()}.
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()}.
Equivalent to close/3
Closes a handle to an open file or directory on the server.
Equivalent to del_dir/3
Deletes a directory specified by Name. The directory must be empty before it
can be successfully deleted.
Equivalent to delete/3
Deletes the file specified by Name.
Equivalent to list_dir/3
Lists the given directory on the server, returning the filenames as a list of strings.
Equivalent to make_dir/3
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.
Equivalent to make_symlink/4
Creates a symbolic link pointing to Target with the name Name.
Equivalent to open/4
Opens a file on the server and returns a handle, which can be used for reading or writing.
Equivalent to open_tar/4
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.
Equivalent to opendir/3
Opens a handle to a directory on the server. The handle can be used for reading directory contents.
Equivalent to position/4
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
Equivalent to pread/5
The pread/3,4 function reads from a specified position, combining the
position/3 and read/3,4 functions.
Equivalent to pwrite/5
The pwrite/3,4 function writes to a specified position, combining the
position/3 and write/3,4 functions.
Equivalent to read/4
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.
Equivalent to read_file/3
Reads a file from the server, and returns the data in a binary.
Equivalent to read_file_info/3
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.
Equivalent to read_link/3
Reads the link target from the symbolic link specified by name.
Equivalent to read_link_info/3
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.
Equivalent to rename/4
Renames a file named OldName and gives it the name NewName.
Equivalent to start_channel/3
Equivalent to start_channel/3
start_channel(Host, Port, Options) ->
Stops an SFTP channel. Does not close the SSH connection. Use ssh:close/1 to
close it.
Equivalent to write/4
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.
Equivalent to write_file/4
Writes a file to the server. The file is created if it does not exist but overwritten if it exists.
Equivalent to write_file_info/4
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.
Types: Error cause
A description of the reason why an operation failed.
The atom/0 value is formed from the sftp error codes in the protocol-level
responses as defined in
draft-ietf-secsh-filexfer-13
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/0 to be no_such_file.
The string/0 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/0 reason are other errors like for example {exit_status,1}.
Types: Crypto operations for open_tar
-type chunk_size() :: undefined | pos_integer().
-type crypto_fun() :: fun((TextIn :: binary(), crypto_state()) -> crypto_result()).
-type crypto_result() :: {ok, TextOut :: binary(), crypto_state()} | {ok, TextOut :: binary(), crypto_state(), chunk_size()}.
The initial crypto_state/0 returned from the init_fun/0 is folded into
repeated applications of the crypto_fun/0 in the
tar_crypto_spec. The binary returned from that fun is
sent to the remote SFTP server and the new crypto_state/0 is used in the
next call of the crypto_fun/0.
If the crypto_fun/0 reurns a chunk_size/0, that value is as block size
for further blocks in calls to crypto_fun/0.
-type crypto_state() :: any().
The init_fun/0 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/0 is the state such a
function may return.
If the selected cipher needs to have the input data partitioned into blocks of a
certain size, the init_fun/0 should return the second form of return value
with the chunk_size/0 set to the block size. If the chunk_size/0 is
undefined, the size of the PlainBins varies, because this is intended for
stream crypto, whereas a fixed chunk_size/0 is intended for block crypto. A
chunk_size/0 can be changed in the return from the crypto_fun/0. The
value can be changed between pos_integer/0 and undefined.
-type 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.
-type encrypt_spec() :: {init_fun(), crypto_fun(), final_fun()}.
-type final_fun() :: fun((FinalTextIn :: binary(), crypto_state()) -> {ok, FinalTextOut :: binary()}).
If doing encryption, the final_fun/0 in the
tar_crypto_spec is applied to the last piece of data.
The final_fun/0 is responsible for padding (if needed) and encryption of
that last piece.
-type init_fun() :: fun(() -> {ok, crypto_state()}) | fun(() -> {ok, crypto_state(), chunk_size()}).
-type tar_crypto_spec() :: encrypt_spec() | decrypt_spec().
Types
-type sftp_option() :: {timeout, timeout()} | {sftp_vsn, pos_integer()} | {window_size, pos_integer()} | {packet_size, pos_integer()}.
Functions
-spec apread(ChannelPid, Handle, Position, Len) -> {async, N} | Error when ChannelPid :: pid(), Handle :: term(), Position :: integer(), Len :: integer(), Error :: {error, reason()}, N :: term().
The apread/4 function reads from a specified position, combining
the position/3 and aread/3 functions.
-spec apwrite(ChannelPid, Handle, Position, Data) -> {async, N} | Error when 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.
-spec aread(ChannelPid, Handle, Len) -> {async, N} | Error when 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 result from the read, either {ok, Data}, eof, or {error, reason()}.
-spec awrite(ChannelPid, Handle, Data) -> {async, N} | Error when 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()}.
-spec close(ChannelPid, Handle) -> ok | Error when ChannelPid :: pid(), Handle :: term(), Error :: {error, reason()}.
Equivalent to close/3
-spec close(ChannelPid, Handle, Timeout) -> ok | Error when ChannelPid :: pid(), Handle :: term(), Timeout :: timeout(), Error :: {error, reason()}.
Closes a handle to an open file or directory on the server.
-spec del_dir(ChannelPid, Name) -> ok | Error when ChannelPid :: pid(), Name :: string(), Error :: {error, reason()}.
Equivalent to del_dir/3
-spec del_dir(ChannelPid, Name, Timeout) -> ok | Error when 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.
-spec delete(ChannelPid, Name) -> ok | Error when ChannelPid :: pid(), Name :: string(), Error :: {error, reason()}.
Equivalent to delete/3
-spec delete(ChannelPid, Name, Timeout) -> ok | Error when ChannelPid :: pid(), Name :: string(), Timeout :: timeout(), Error :: {error, reason()}.
Deletes the file specified by Name.
-spec list_dir(ChannelPid, Path) -> {ok, FileNames} | Error when ChannelPid :: pid(), Path :: string(), FileNames :: [FileName], FileName :: string(), Error :: {error, reason()}.
Equivalent to list_dir/3
-spec list_dir(ChannelPid, Path, Timeout) -> {ok, FileNames} | Error when 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.
-spec make_dir(ChannelPid, Name) -> ok | Error when ChannelPid :: pid(), Name :: string(), Error :: {error, reason()}.
Equivalent to make_dir/3
-spec make_dir(ChannelPid, Name, Timeout) -> ok | Error when 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 existing directory.
-spec make_symlink(ChannelPid, Name, Target) -> ok | Error when ChannelPid :: pid(), Name :: string(), Target :: string(), Error :: {error, reason()}.
Equivalent to make_symlink/4
-spec make_symlink(ChannelPid, Name, Target, Timeout) -> ok | Error when ChannelPid :: pid(), Name :: string(), Target :: string(), Timeout :: timeout(), Error :: {error, reason()}.
Creates a symbolic link pointing to Target with the name Name.
-spec open(ChannelPid, Name, Mode) -> {ok, Handle} | Error when ChannelPid :: pid(), Name :: string(), Mode :: [read | write | append | binary | raw], Handle :: term(), Error :: {error, reason()}.
Equivalent to open/4
-spec open(ChannelPid, Name, Mode, Timeout) -> {ok, Handle} | Error when 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.
-spec open_tar(ChannelPid, Path, Mode) -> {ok, Handle} | Error when ChannelPid :: pid(), Path :: string(), Mode :: [read | write | {crypto, tar_crypto_spec()}], Handle :: term(), Error :: {error, reason()}.
Equivalent to open_tar/4
-spec open_tar(ChannelPid, Path, Mode, Timeout) -> {ok, Handle} | Error when 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.
-spec opendir(ChannelPid, Path) -> {ok, Handle} | Error when ChannelPid :: pid(), Path :: string(), Handle :: term(), Error :: {error, reason()}.
Equivalent to opendir/3
-spec opendir(ChannelPid, Path, Timeout) -> {ok, Handle} | Error when 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.
-spec position(ChannelPid, Handle, Location) -> {ok, NewPosition} | Error when ChannelPid :: pid(), Handle :: term(), Location :: Offset | {bof, Offset} | {cur, Offset} | {eof, Offset} | bof | cur | eof, Offset :: integer(), NewPosition :: integer(), Error :: {error, reason()}.
Equivalent to position/4
-spec position(ChannelPid, Handle, Location, Timeout) -> {ok, NewPosition} | Error when ChannelPid :: pid(), Handle :: term(), Location :: Offset | {bof, Offset} | {cur, Offset} | {eof, Offset} | bof | cur | eof, Timeout :: timeout(), Offset :: integer(), NewPosition :: integer(), Error :: {error, reason()}.
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 withOffset` 0, that is,`{bof, 0} {cur, 0} {eof, 0}`.
-spec pread(ChannelPid, Handle, Position, Len) -> {ok, Data} | eof | Error when ChannelPid :: pid(), Handle :: term(), Position :: integer(), Len :: integer(), Data :: string() | binary(), Error :: {error, reason()}.
Equivalent to pread/5
-spec pread(ChannelPid, Handle, Position, Len, Timeout) -> {ok, Data} | eof | Error when ChannelPid :: pid(), Handle :: term(), Position :: integer(), Len :: integer(), Timeout :: timeout(), Data :: string() | binary(), Error :: {error, reason()}.
The pread/3,4 function reads from a specified position, combining the
position/3 and read/3,4 functions.
-spec pwrite(ChannelPid, Handle, Position, Data) -> ok | Error when ChannelPid :: pid(), Handle :: term(), Position :: integer(), Data :: iolist(), Error :: {error, reason()}.
Equivalent to pwrite/5
-spec pwrite(ChannelPid, Handle, Position, Data, Timeout) -> ok | Error when ChannelPid :: pid(), Handle :: term(), Position :: integer(), Data :: iolist(), Timeout :: timeout(), Error :: {error, reason()}.
The pwrite/3,4 function writes to a specified position, combining the
position/3 and write/3,4 functions.
-spec read(ChannelPid, Handle, Len) -> {ok, Data} | eof | Error when ChannelPid :: pid(), Handle :: term(), Len :: integer(), Data :: string() | binary(), Error :: {error, reason()}.
Equivalent to read/4
-spec read(ChannelPid, Handle, Len, Timeout) -> {ok, Data} | eof | Error when 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 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.
-spec read_file(ChannelPid, File) -> {ok, Data} | Error when ChannelPid :: pid(), File :: string(), Data :: binary(), Error :: {error, reason()}.
Equivalent to read_file/3
-spec read_file(ChannelPid, File, Timeout) -> {ok, Data} | Error when ChannelPid :: pid(), File :: string(), Data :: binary(), Timeout :: timeout(), Error :: {error, reason()}.
Reads a file from the server, and returns the data in a binary.
-spec read_file_info(ChannelPid, Name) -> {ok, FileInfo} | Error when ChannelPid :: pid(), Name :: string(), FileInfo :: file:file_info(), Error :: {error, reason()}.
Equivalent to read_file_info/3
-spec read_file_info(ChannelPid, Name, Timeout) -> {ok, FileInfo} | Error when 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.
-spec read_link(ChannelPid, Name) -> {ok, Target} | Error when ChannelPid :: pid(), Name :: string(), Target :: string(), Error :: {error, reason()}.
Equivalent to read_link/3
-spec read_link(ChannelPid, Name, Timeout) -> {ok, Target} | Error when ChannelPid :: pid(), Name :: string(), Target :: string(), Timeout :: timeout(), Error :: {error, reason()}.
Reads the link target from the symbolic link specified by name.
-spec read_link_info(ChannelPid, Name) -> {ok, FileInfo} | Error when ChannelPid :: pid(), Name :: string(), FileInfo :: file:file_info(), Error :: {error, reason()}.
Equivalent to read_link_info/3
-spec read_link_info(ChannelPid, Name, Timeout) -> {ok, FileInfo} | Error when 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.
-spec rename(ChannelPid, OldName, NewName) -> ok | Error when ChannelPid :: pid(), OldName :: string(), NewName :: string(), Error :: {error, reason()}.
Equivalent to rename/4
-spec rename(ChannelPid, OldName, NewName, Timeout) -> ok | Error when ChannelPid :: pid(), OldName :: string(), NewName :: string(), Timeout :: timeout(), Error :: {error, reason()}.
Renames a file named OldName and gives it the name NewName.
-spec start_channel(ssh:open_socket() | ssh:connection_ref() | ssh:host()) -> {ok, pid()} | {ok, pid(), ssh:connection_ref()} | {error, reason()}.
Equivalent to start_channel/3
-spec start_channel(ssh:open_socket(), [ssh:client_option() | sftp_option()]) -> {ok, pid(), ssh:connection_ref()} | {error, reason()}; (ssh:connection_ref(), [sftp_option()]) -> {ok, pid()} | {ok, pid(), ssh:connection_ref()} | {error, reason()}; (ssh:host(), [ssh:client_option() | sftp_option()]) -> {ok, pid(), ssh:connection_ref()} | {error, reason()}.
Equivalent to start_channel/3
-spec start_channel(ssh:host(), inet:port_number(), [ssh:client_option() | sftp_option()]) -> {ok, pid(), ssh:connection_ref()} | {error, reason()}.
start_channel(Host, Port, Options) ->
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_timeoutis 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.- If the connection timeout option
{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.
-spec stop_channel(ChannelPid) -> ok when ChannelPid :: pid().
Stops an SFTP channel. Does not close the SSH connection. Use ssh:close/1 to
close it.
-spec write(ChannelPid, Handle, Data) -> ok | Error when ChannelPid :: pid(), Handle :: term(), Data :: iodata(), Error :: {error, reason()}.
Equivalent to write/4
-spec write(ChannelPid, Handle, Data, Timeout) -> ok | Error when 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.
-spec write_file(ChannelPid, File, Data) -> ok | Error when ChannelPid :: pid(), File :: string(), Data :: iodata(), Error :: {error, reason()}.
Equivalent to write_file/4
-spec write_file(ChannelPid, File, Data, Timeout) -> ok | Error when 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.
-spec write_file_info(ChannelPid, Name, FileInfo) -> ok | Error when ChannelPid :: pid(), Name :: string(), FileInfo :: file:file_info(), Error :: {error, reason()}.
Equivalent to write_file_info/4
-spec write_file_info(ChannelPid, Name, FileInfo, Timeout) -> ok | Error when 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
information about the record.