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ftp - Client-side tcl implementation of the ftp protocol
package require Tcl
package require ftp ?2.3?
package require ftp::geturl ?0.1? ; # for ftp::geturl command
ftp::Open server user passwd ?options?
ftp::Close handle
ftp::Cd handle directory
ftp::Pwd handle
ftp::Type handle ?ascii|binary|tenex?
ftp::List handle ?directory?
ftp::NList handle ?directory?
ftp::FileSize handle file
ftp::ModTime handle file
ftp::Delete handle file
ftp::Rename handle from to
ftp::Put handle (local | -data data | -channel chan) ?remote?
ftp::Append handle (local | -data data | -channel chan) ?remote?
ftp::Get handle remote ?(local | -variable varname | -channel chan)?
ftp::Reget handle remote ?local? ?from? ?to?
ftp::Newer handle remote ?local?
ftp::MkDir handle directory
ftp::RmDir handle directory
ftp::Quote handle arg1 arg2 ...
ftp::DisplayMsg handle msg ?state?
ftp::geturl url
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The ftp library package provides the client side of the ftp protocol. The package implements both active (default) and passive ftp sessions.
A new ftp session is started with the Open command. To shutdown an existing ftp session use Close. All other commands are restricted to usage in an an open ftp session. They will generate errors if they are used out of context. The ftp package includes file and directory manipulating commands for remote sites. To perform the same operations on the local site use commands built into the core, like cd or file.
The output of the package is controlled by two state variables, ftp::VERBOSE and ftp::DEBUG. Setting ftp::VERBOSE to 1 forces the package to show all responses from a remote server. The default value is 0. Setting ftp::DEBUG to 1 enables debugging and forces the package to show all return codes, states, state changes and «real» ftp commands. The default value is 0.
The procedure DisplayMsg is used to show the different messages from the ftp session. The setting of VERBOSE determines if this command is called or not. The current implementation of the command uses the log module of tcllib to write the messages to their final destination. This means that the behaviour of DisplayMsg can be customized without changing its implementation. For more radical changes overwriting its implementation by the application is of course still possible. Note that the default implementation honors the -output option to ftp::Open for a session specific log command.
Caution: The default implementation logs error messages like all other messages. If this behaviour is changed to throwing an error instead all commands in the API will change their behaviour too. In such a case they will not return a failure code as described below but pass the thrown error to their caller.
ftp::geturl url
This command lives in its own package, ftp::geturl,
and can be used by the generic uri::geturl command
to retrieve the contents of ftp urls. Internally it
uses the ftp commands described below to fulfill
the request.
The contents of an ftp url are defined as follows:
directory
A listing of the contents of the directory
in key value notation where the file name is
the key and its attributes the associated
value.
link The attributes of the link, including the path it refers to.
ftp::Open server user passwd ?options?
This command is used to start a FTP session by
establishing a control connection to the FTP
server. The defaults are used for any option not
specified by the caller.
The command takes a host name server, a user name user and a password password as its parameters and returns a session handle that is an integer number greater than or equal to 0, if the connection is successfully established. Otherwise it returns -1. The server parameter must be the name or internet address (in dotted decimal notation) of the ftp server to connect to. The user and passwd parameters must contain a valid user name and password to complete the login process.
The options overwrite some default values or set special abilities:
When evaluating the callback one argument is appended to the callback script, the current accumulated number of bytes transferred so far.
When evaluating the callback several arguments are appended to the callback script, namely the keyword of the operation that has completed and any additional arguments specific to the operation. If an error occured during the execution of the operation the callback is given the keyword error.
ftp::Close handle
This command terminates the specified ftp session.
If no file transfer is in progress, the server will
close the control connection immediately. If a file
transfer is in progress however, the control connection
will remain open until the transfers completes.
When that happens the server will write the
result response for the transfer to it and close
the conenction afterward.
ftp::Cd handle directory
This command changes the current working directory
on the ftp server to a specified target directory.
The command returns 1 if the current working directory
was successfully changed to the specified
directory or 0 if it fails. The target directory
can be
ftp::Pwd handle
This command returns the complete path of the current
working directory on the ftp server, or an
empty string in case of an error.
ftp::Type handle ?ascii|binary|tenex?
This command sets the ftp file transfer type to
either ascii, binary, or tenex. The command always
returns the currently set type. If called without
type no change is made.
Currently only ascii and binary types are supported. There is some early (alpha) support for Tenex mode. The type ascii is normally used to convert text files into a format suitable for text editors on the platform of the destination machine. This mainly affects end-of-line markers. The type binary on the other hand allows the undisturbed transfer of non-text files, such as compressed files, images and executables.
ftp::List handle ?pattern?
This command returns a human-readable list of
files. Wildcard expressions such as *.tcl are
allowed. If pattern refers to a specific directory,
then the contents of that directory are
returned. If the pattern is not a fully-qualified
path name, the command lists entries relative to
the current remote directory. If no pattern is
specified, the contents of the current remote
directory is returned.
The listing includes any system-dependent information that the server chooses to include. For example most UNIX systems produce output from the command ls -l. The command returns the retrieved information as a tcl list with one item per entry. Empty lines and UNIX's «total» lines are ignored and not included in the result as reported by this command.
If the command fails an empty list is returned.
ftp::NList handle ?directory?
This command has the same behavior as the ftp::List
command, except that it only retrieves an abbreviated
listing. This means only file names are
returned in a sorted list.
ftp::FileSize handle file
This command returns the size of the specified file
on the ftp server. If the command fails an empty
string is returned.
ATTENTION! It will not work properly when in ascii mode and is not supported by all ftp server implementations.
ftp::ModTime handle file
This command retrieves the time of the last modification
of the file on the ftp server as a system
dependent integer value in seconds or an empty
string if an error occured. Use the built-in command
clock to convert the retrieves value into
other formats.
ftp::Delete handle file
This command deletes the specified file on the ftp
server. The command returns 1 if the specified file
was successfully deleted or 0 if it failed.
ftp::Rename handle from to
This command renames the file from in the current
directory of the ftp server to the specified new
file name to. This new file name must not be the
same as any existing subdirectory or file name.
The command returns 1 if the specified file was
successfully renamed or 0 if it failed.
ftp::Put handle (local | -data data | -channel chan)
?remote?
This command transfers a local file local to a
remote file remote on the ftp server. If the file
parameters passed to the command do not fully qualified
path names the command will use the current
directory on local and remote host. If the remote
file name is unspecified, the server will use the
name of the local file as the name of the remote
file. The command returns 1 to indicate a sucessful
transfer and 0 in the case of a failure.
If -data data is specified instead of a local file, the system will not transfer a file, but the data passed into it. In this case the name of the remote file has to be specified.
If -channel chan is specified instead of a local file, the system will not transfer a file, but read the contents of the channel chan and write this to the remote file. In this case the name of the remote file has to be specified. After the transfer chan will be closed.
ftp::Append handle (local | -data data | -channel chan)
?remote?
This command behaves like ftp::Puts, but appends
the transfered information to the remote file. If
the file did not exist on the server it will be
created.
ftp::Get handle remote ?(local | -variable varname
-channel chan)?
This command retrieves a remote file remote on the
ftp server and stores its contents into the local
file local. If the file parameters passed to the
command are not fully qualified path names the command
will use the current directory on local and
remote host. If the local file name is unspecified,
the server will use the name of the remote file as
the name of the local file. The command returns 1
to indicate a sucessful transfer and 0 in the case
of a failure. The command will throw an error if
the directory the file local is to be placed in
does not exist.
If -variable varname is specified, the system will store the retrieved data into the variable varname instead of a file.
If -channel chan is specified, the system will write the retrieved data into the channel chan instead of a file. The system will not close chan after the transfer, this is the responsibility of the caller to Get.
ftp::Reget handle remote ?local? ?from? ?to? This command behaves like ftp::Get, except that if local file local exists and is smaller than remote file remote, the local file is presumed to be a partially transferred copy of the remote file and the transfer is continued from the apparent point of failure. The command will throw an error if the directory the file local is to be placed in does not exist. This command is useful when transferring very large files over networks that tend to drop connections.
Specifying the additional byte offsets from and to will cause the command to change its behaviour and to download exactly the specified slice of the remote file. This mode is possible only if a local destination is explicitly provided. Omission of to leads to downloading till the end of the file.
ftp::Newer handle remote ?local?
This command behaves like ftp::Get, except that it
retrieves the remote file only if the modification
time of the remote file is more recent than the
file on the local system. If the file does not
exist on the local system, the remote file is considered
newer. The command will throw an error if
the directory the file local is to be placed in
does not exist.
ftp::MkDir handle directory
This command creates the specified directory on the
ftp server. If the specified path is relative the
new directory will be created as a subdirectory of
the current working directory. Else the created
directory will have the specified path name. The
command returns 1 to indicate a sucessful creation
of the directory and 0 in the case of a failure.
ftp::RmDir handle directory
This command removes the specified directory on the
ftp server. The remote directory has to be empty or
the command will fail. The command returns 1 to
indicate a sucessful removal of the directory and 0
in the case of a failure.
ftp::Quote handle arg1 arg2 ...
This command is used to send an arbitrary ftp command
to the server. It cannot be used to obtain a
directory listing or for transferring files. It is
included to allow an application to execute commands
on the ftp server which are not provided by
this package. The arguments are sent verbatim,
i.e. as is, with no changes.
In constrast to the other commands in this package this command will not parse the response it got from the ftp server but return it verbatim to the caller.
ftp::DisplayMsg handle msg ?state?
This command is used by the package itself to show
the different messages from the ftp sessions. The
package itself declares this command very simple,
writing the messages to stdout (if VERBOSE was set,
see below) and throwing tcl errors for error messages.
It is the responsibility of the application
to overwrite it as needed. A state variable for
different states assigned to different colors is
recommended by the author. The log package can be
useful for this.
ftp::VERBOSE
A state variable controlling the output of the
package. Setting ftp::VERBOSE to 1 forces the package
to show all responses from a remote server. The
default value is 0.
ftp::DEBUG
A state variable controlling the output of ftp.
Setting ftp::DEBUG to 1 enables debugging and
forces the package to show all return codes,
states, state changes and «real» ftp commands. The
default value is 0.
The correct execution of many commands depends upon the proper behavior by the remote server, network and router configuration.
An update command placed in the procedure DisplayMsg may run into persistent errors or infinite loops. The solution to this problem is to use update idletasks instead of update.
ftpd, smtp, pop3, mime
ftp, rfc959, internet, net