Class: Net::SFTP::Session

Class | Net::SFTP::Session
In: | lib/net/sftp/session.rb
Parent: | Object

The Session class encapsulates a single SFTP channel on a Net::SSH connection. Instances of this class are what most applications will interact with most, as it provides access to both low-level (mkdir, rename, remove, symlink, etc.) and high-level (upload, download, etc.) SFTP operations.

Although Session makes it easy to do SFTP operations serially, you can also set up multiple operations to be done in parallel, too, without needing to resort to threading. You merely need to fire off the requests, and then run the event loop until all of the requests have completed:

      handle1 = sftp.open!("/path/to/file1")
      handle2 = sftp.open!("/path/to/file2")

      r1 = sftp.read(handle1, 0, 1024)
      r2 = sftp.read(handle2, 0, 1024)
      sftp.loop { [r1, r2].any? { |r| r.pending? } }

      puts "chunk #1: #{r1.response[:data]}"
      puts "chunk #2: #{r2.response[:data]}"

By passing blocks to the operations, you can set up powerful state machines, to fire off subsequent operations. In fact, the Net::SFTP::Operations::Upload and Net::SFTP::Operations::Download classes set up such state machines, so that multiple uploads and/or downloads can be running simultaneously.

The convention with the names of the operations is as follows: if the method name ends with an exclamation mark, like read!, it will be synchronous (e.g., it will block until the server responds). Methods without an exclamation mark (e.g. read) are asynchronous, and return before the server has responded. You will need to make sure the SSH event loop is run in order to process these requests. (See loop.)

### Methods

block block! close close! close_channel closed? connect connect! dir download download! file fsetstat fsetstat! fstat fstat! link link! loop lstat lstat! mkdir mkdir! new open open! open? opendir opendir! opening? read read! readdir readdir! readlink readlink! realpath realpath! remove remove! rename rename! rmdir rmdir! send_packet setstat setstat! stat stat! symlink symlink! unblock unblock! upload upload! write write!

### Included Modules

Net::SSH::Loggable Net::SFTP::Constants::PacketTypes

### Constants

HIGHEST_PROTOCOL_VERSION_SUPPORTED | = | 6 |  | The highest protocol version supported by the Net::SFTP library.

### External Aliases

loop | -> | loop_forever

### Attributes

channel | [R] | The Net::SSH::Connection::Channel object that the SFTP session is being processed by.
pending_requests | [R] | The hash of pending requests. Any requests that have been sent and which the server has not yet responded to will be represented here.
protocol | [R] | The protocol instance being used by this SFTP session. Useful for querying the protocol version in effect.
session | [R] | A reference to the Net::SSH session object that powers this SFTP session.
state | [R] | The state of the SFTP connection. It will be :opening, :subsystem, :init, :open, or :closed.

### Public Class methods

new(session, &block)

Creates a new Net::SFTP instance atop the given Net::SSH connection. This will return immediately, before the SFTP connection has been properly initialized. Once the connection is ready, the given block will be called. If you want to block until the connection has been initialized, try this:

      sftp = Net::SFTP::Session.new(ssh)
      sftp.loop { sftp.opening? }

### Public Instance methods

block(handle, offset, length, mask) → request
block(handle, offset, length, mask) { |response| ... } → request

Creates a byte-range lock on the file specified by the given `handle`. This operation is only available in SFTP protocol versions 6 and higher. The lock may be either mandatory or advisory.

The `handle` parameter is a file handle, as obtained by the open method.

The `offset` and `length` parameters describe the location and size of the byte range.

The `mask` describes how the lock should be defined, and consists of some combination of the following bit masks:

- 0x0040 - Read lock. The byte range may not be accessed for reading by via any other handle, though it may be written to.
- 0x0080 - Write lock. The byte range may not be written to via any other handle, though it may be read from.
- 0x0100 - Delete lock. No other handle may delete this file.
- 0x0200 - Advisory lock. The server need not honor the lock instruction.

Once created, the lock may be removed via the unblock method.

block!(handle, offset, length, mask, &callback)

Identical to block, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the Response object for the request.

close(handle) → request
close(handle) { |response| ... } → request

Closes an open handle, whether obtained via open, or opendir. Returns immediately with a Request object. If a block is given, it will be invoked when the server responds.

      sftp.open("/path/to/file") do |response|
        raise "fail!" unless response.ok?
        sftp.close(response[:handle])
      end
      sftp.loop

close!(handle, &callback)

Identical to close, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it returns the Response object for this request.

      sftp.close!(handle)

close_channel()

Closes the SFTP connection, but not the SSH connection. Blocks until the session has terminated. Once the session has terminated, further operations on this object will result in errors. You can reopen the SFTP session via the connect method.

closed?()

Returns true if the connection has been closed.

connect(&block)

Attempts to establish an SFTP connection over the SSH session given when this object was instantiated. If the object is already open, this will simply execute the given block (if any), passing the SFTP session itself as argument. If the session is currently being opened, this will add the given block to the list of callbacks, to be executed when the session is fully open.

This method does not block, and will return immediately. If you pass a block to it, that block will be invoked when the connection has been fully established. Thus, you can do something like this:

      sftp.connect do
        puts "open!"
      end

If you just want to block until the connection is ready, see the connect! method.

connect!(&block)

Same as the connect method, but blocks until the SFTP connection has been fully initialized.

dir()

Returns a Net::SFTP::Operations::Dir instance, which can be used to conveniently iterate over and search directories on the remote server.

     sftp.dir.glob("/base/path", "*/**/*.rb") do |entry|
       p entry.name
     end

See Net::SFTP::Operations::Dir for a more detailed discussion of how to use this.

download(remote, local, options={}, &block)

Initiates a download from `remote` to `local`, asynchronously. This method will return a new Net::SFTP::Operations::Download instance, and requires that the event loop be run in order for the download to progress. See Net::SFTP::Operations::Download for a full discussion of hos this method can be used.

      download = sftp.download("/remote/path", "/local/path")
      download.wait

download!(remote, local=nil, options={}, &block)

Identical to download, but blocks until the download is complete. If `local` is omitted, downloads the file to an in-memory buffer and returns the result as a string; otherwise, returns the Net::SFTP::Operations::Download instance.

file()

Returns an Net::SFTP::Operations::FileFactory instance, which can be used to mimic synchronous, IO-like file operations on a remote file via SFTP.

      sftp.file.open("/path/to/file") do |file|
        while line = file.gets
          puts line
        end
      end

See Net::SFTP::Operations::FileFactory and Net::SFTP::Operations::File for more details.

fsetstat(handle, attrs, &callback)

The fsetstat method is identical to the setstat method, with the exception that it takes a `handle` as the first parameter, such as would be obtained via the open or opendir methods. (See the setstat method for full documentation.)

fsetstat!(handle, attrs, &callback)

Identical to the fsetstat method, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the Response object for the request.

      sftp.fsetstat!(handle, :permissions => 0644)

fstat(handle, flags=nil, &callback)

The fstat method is identical to the stat and lstat methods, with the exception that it takes a `handle` as the first parameter, such as would be obtained via the open or opendir methods. (See the lstat method for full documentation).

fstat!(handle, flags=nil, &callback)

Identical to the fstat method, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the attribute object describing the path.

      puts sftp.fstat!(handle).permissions

link(new_link_path, existing_path, symlink=true) → request
link(new_link_path, existing_path, symlink=true) { |response| ... } → request

Attempts to create a link, either hard or symbolic. This operation is only available in SFTP protocol versions 6 and higher. If the `symlink` paramter is true, a symbolic link will be created, otherwise a hard link will be created. The link will be named `new_link_path`, and will point to the path `existing_path`.

      sftp.link("/path/to/symlink", "/path/to/file", true).wait

Note that link is only available for SFTP protocol 6 and higher. You can use symlink for protocols 3 and higher.

link!(new_link_path, existing_path, symlink=true, &callback)

Identical to link, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the Response object for the request.

      sftp.link!("/path/to/symlink", "/path/to/file", true)

loop(&block)

Runs the SSH event loop while the given block returns true. This lets you set up a state machine and then "fire it off". If you do not specify a block, the event loop will run for as long as there are any pending SFTP requests. This makes it easy to do thing like this:

      sftp.remove("/path/to/file")
      sftp.loop

lstat(path, flags=nil) → request
lstat(path, flags=nil) { |response| ... } → request

This method is identical to the stat method, with the exception that it will not follow symbolic links (thus allowing you to stat the link itself, rather than what it refers to). The `flags` parameter is not used in SFTP protocol versions prior to 4, and will be ignored in those versions of the protocol that do not use it. For those that do, however, you may provide hints as to which file proprties you wish to query (e.g., if all you want is permissions, you could pass the Net::SFTP::Protocol::V04::Attributes::F_PERMISSIONS flag as the value for the `flags` parameter).

The method returns immediately with a Request object. If a block is given, it will be invoked when the server responds. The :attrs property of the response will contain an Attributes instance appropriate for the the protocol version (see Protocol::V01::Attributes, Protocol::V04::Attributes, and Protocol::V06::Attributes).

      request = sftp.lstat("/path/to/file") do |response|
        raise "fail!" unless response.ok?
        puts "permissions: %04o" % response[:attrs].permissions
      end
      request.wait

lstat!(path, flags=nil, &callback)

Identical to the lstat method, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the attribute object describing the path.

      puts sftp.lstat!("/path/to/file").permissions

mkdir(path, attrs={}) → request
mkdir(path, attrs={}) { |response| ... } → request

Creates the named directory on the remote server. If an attribute hash is given, it must map to the set of attributes supported by the version of the SFTP protocol in use. (See Protocol::V01::Attributes, Protocol::V04::Attributes, and Protocol::V06::Attributes.)

      sftp.mkdir("/path/to/directory", :permissions => 0550).wait

mkdir!(path, attrs={}, &callback)

Identical to mkdir, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the Response object for the request.

      sftp.mkdir!("/path/to/directory", :permissions => 0550)

open(path, flags="r", options={}) → request
open(path, flags="r", options={}) { |response| ... } → request

Opens a file on the remote server. The `flags` parameter determines how the flag is open, and accepts the same format as IO#open (e.g., either a string like "r" or "w", or a combination of the IO constants). The `options` parameter is a hash of attributes to be associated with the file, and varies greatly depending on the SFTP protocol version in use, but some (like :permissions) are always available.

Returns immediately with a Request object. If a block is given, it will be invoked when the server responds, with a Response object as the only parameter. The :handle property of the response is the handle of the opened file, and may be passed to other methods (like close, read, write, and so forth).

      sftp.open("/path/to/file") do |response|
        raise "fail!" unless response.ok?
        sftp.close(response[:handle])
      end
      sftp.loop

open!(path, flags="r", options={}, &callback)

Identical to open, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the handle of the newly opened file.

      handle = sftp.open!("/path/to/file")

open?()

Returns true if the connection has been initialized.

opendir(path) → request
opendir(path) { |response| ... } → request

Attempts to open a directory on the remote host for reading. Once the handle is obtained, directory entries may be retrieved using the readdir method. The method returns immediately with a Request object. If a block is given, it will be invoked when the server responds.

      sftp.opendir("/path/to/directory") do |response|
        raise "fail!" unless response.ok?
        sftp.close(response[:handle])
      end
      sftp.loop

opendir!(path, &callback)

Identical to opendir, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return a handle to the given path.

      handle = sftp.opendir!("/path/to/directory")

opening?()

Returns true if the connection is in the process of being initialized (e.g., it is not closed, but is not yet fully open).

read(handle, offset, length) → request
read(handle, offset, length) { |response| ... } → request

Requests that `length` bytes, starting at `offset` bytes from the beginning of the file, be read from the file identified by `handle`. (The `handle` should be a value obtained via the open method.) Returns immediately with a Request object. If a block is given, it will be invoked when the server responds.

The :data property of the response will contain the requested data, assuming the call was successful.

      request = sftp.read(handle, 0, 1024) do |response|
        if response.eof?
          puts "end of file reached before reading any data"
        elsif !response.ok?
          puts "error (#{response})"
        else
          print(response[:data])
        end
      end
      request.wait

To read an entire file will usually require multiple calls to read, unless you know in advance how large the file is.

read!(handle, offset, length, &callback)

Identical to read, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. If the end of the file was reached, `nil` will be returned. Otherwise, it returns the data that was read, as a String.

      data = sftp.read!(handle, 0, 1024)

readdir(handle) → request
raeddir(handle) { |response| ... } → request

Reads a set of entries from the given directory handle (which must have been obtained via opendir). If the response is EOF, then there are no more entries in the directory. Otherwise, the entries will be in the :names property of the response:

      loop do
        request = sftp.readdir(handle).wait
        break if request.response.eof?
        raise "fail!" unless request.response.ok?
        request.response[:names].each do |entry|
           puts entry.name
        end
      end

See also Protocol::V01::Name and Protocol::V04::Name for the specific properties of each individual entry (which vary based on the SFTP protocol version in use).

readdir!(handle, &callback)

Identical to readdir, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return nil if there were no more names to read, or an array of name entries.

      while (entries = sftp.readdir!(handle)) do
        entries.each { |entry| puts(entry.name) }
      end

readlink(path) → request
readlink(path) { |response| ... } → request

Queries the server for the target of the specified symbolic link. This operation is only available in protocol versions 3 and higher. The response to this request will include a names property, a one-element array naming the target of the symlink.

      request = sftp.readlink("/path/to/symlink").wait
      puts request.response[:names].first.name

readlink!(path, &callback)

Identical to readlink, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the Name object for the path that the symlink targets.

      item = sftp.readlink!("/path/to/symlink")

realpath(path) → request
realpath(path) { |response| ... } → request

Tries to canonicalize the given path, turning any given path into an absolute path. This is primarily useful for converting a path with ".." or "." segments into an identical path without those segments. The answer will be in the response‘s :names attribute, as a one-element array.

      request = sftp.realpath("/path/../to/../directory").wait
      puts request[:names].first.name

realpath!(path, &callback)

Identical to realpath, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return a name object identifying the path.

      puts(sftp.realpath!("/path/../to/../directory"))

remove(filename) → request
remove(filename) { |response| ... } → request

Attempts to remove the given file from the remote file system. Returns immediately with a Request object. If a block is given, the block will be invoked when the server responds, and will be passed a Response object.

      sftp.remove("/path/to/file").wait

remove!(filename, &callback)

Identical to remove, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the Response object for the request.

      sftp.remove!("/path/to/file")

rename(name, new_name, flags=nil) → request
rename(name, new_name, flags=nil) { |response| ... } → request

Renames the given file. This operation is only available in SFTP protocol versions two and higher. The `flags` parameter is ignored in versions prior to 5. In versions 5 and higher, the `flags` parameter can be used to specify how the rename should be performed (atomically, etc.).

The following flags are defined in protocol version 5:

- 0x0001 - overwrite an existing file if the new name specifies a file that already exists.
- 0x0002 - perform the rewrite atomically.
- 0x0004 - allow the server to perform the rename as it prefers.

rename!(name, new_name, flags=nil, &callback)

Identical to rename, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the Response object for the request.

      sftp.rename!("/path/to/old", "/path/to/new")

rmdir(path) → request
rmdir(path) { |response| ... } → request

Removes the named directory on the remote server. The directory must be empty before it can be removed.

      sftp.rmdir("/path/to/directory").wait

rmdir!(path, &callback)

Identical to rmdir, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the Response object for the request.

      sftp.rmdir!("/path/to/directory")

send_packet(type, *args)

Formats, constructs, and sends an SFTP packet of the given type and with the given data. This does not block, but merely enqueues the packet for sending and returns.

You should probably use the operation methods, rather than building and sending the packet directly. (See open, close, etc.)

setstat(path, attrs) → request
setstat(path, attrs) { |response| ... } → request

This method may be used to set file metadata (such as permissions, or user/group information) on a remote file. The exact metadata that may be tweaked is dependent on the SFTP protocol version in use, but in general you may set at least the permissions, user, and group. (See Protocol::V01::Attributes, Protocol::V04::Attributes, and Protocol::V06::Attributes for the full lists of attributes that may be set for the different protocols.)

The `attrs` parameter is a hash, where the keys are symbols identifying the attributes to set.

The method returns immediately with a Request object. If a block is given, it will be invoked when the server responds.

      request = sftp.setstat("/path/to/file", :permissions => 0644)
      request.wait
      puts "success: #{request.response.ok?}"

setstat!(path, attrs, &callback)

Identical to the setstat method, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the Response object for the request.

      sftp.setstat!("/path/to/file", :permissions => 0644)

stat(path, flags=nil, &callback)

Identical to the lstat method, except that it follows symlinks (e.g., if you give it the path to a symlink, it will stat the target of the symlink rather than the symlink itself). See the lstat method for full documentation.

stat!(path, flags=nil, &callback)

Identical to stat, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return an attribute object for the named path.

      attrs = sftp.stat!("/path/to/file")

symlink(path, target) → request
symlink(path, target) { |response| ... } → request

Attempts to create a symlink to `path` at `target`. This operation is only available in protocol versions 3, 4, and 5, but the Net::SFTP library mimics the symlink behavior in protocol version 6 using the link method, so it is safe to use this method in protocol version 6.

      sftp.symlink("/path/to/file", "/path/to/symlink").wait

symlink!(path, target, &callback)

Identical to symlink, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the Response object for the request.

      sftp.symlink!("/path/to/file", "/path/to/symlink")

unblock(handle, offset, length) → request
unblock(handle, offset, length) { |response| ... } → request

Removes a previously created byte-range lock. This operation is only available in protocol versions 6 and higher. The `offset` and `length` parameters must exactly match those that were given to block when the lock was acquired.

unblock!(handle, offset, length, &callback)

Identical to unblock, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful. Otherwise, it will return the Response object for the request.

upload(local, remote, options={}, &block)

Initiates an upload from `local` to `remote`, asynchronously. This method will return a new Net::SFTP::Operations::Upload instance, and requires the event loop to be run in order for the upload to progress. See Net::SFTP::Operations::Upload for a full discussion of how this method can be used.

      uploader = sftp.upload("/local/path", "/remote/path")
      uploader.wait

upload!(local, remote, options={}, &block)

Identical to upload, but blocks until the upload is complete.

write(handle, offset, data) → request
write(handle, offset, data) { |response| ... } → request

Requests that `data` be written to the file identified by `handle`, starting at `offset` bytes from the start of the file. The file must have been opened for writing via open. Returns immediately with a Request object. If a block is given, it will be invoked when the server responds.

      request = sftp.write(handle, 0, "hello, world!\n")
      request.wait

write!(handle, offset, data, &callback)

Identical to write, but blocks until the server responds. It will raise a StatusException if the request was unsuccessful, or the end of the file was reached. Otherwise, it returns the Response object for this request.

      sftp.write!(handle, 0, "hello, world!\n")

[Validate]