transfer::receiver -
Data source
package require Tcl 8.4
package require snit ? 1.0 ?
package require transfer::data::destination ? 0.2 ?
package require transfer::connect ? 0.2 ?
package require transfer::receiver ? 0.2 ?
transfer::receiver object ? options... ?
transfer::receiver stream channel chan host port ? arg... ?
transfer::receiver stream file path host port ? arg... ?
objectName method ? arg arg ... ?
objectName destroy
objectName start
objectName busy
This package pulls data destinations and connection setup together
into a combined object for the reception of information coming in over
a socket.
These objects understand all the options from objects created by the
packages transfer::data::destination and
transfer::connect.
-
transfer::receiver object ? options... ?
-
This command creates a new receiver object with an associated Tcl
command whose name is objectName.
This object command is explained in full detail in the sections
Object command and Object methods. The set of
supported options is explained in section Options.
The object command will be created under the current namespace if the
objectName is not fully qualified, and in the specified
namespace otherwise.
The fully qualified name of the object command is returned as the
result of the command.
-
transfer::receiver stream channel chan host port ? arg... ?
-
This method creates a fire-and-forget transfer for the data coming
from the source at host/port (details below) and writing to the
channel chan, starting at the current seek location. The channel
is configured to use binary translation and encoding for the transfer.
The channel is not closed when the transfer has completed. This
is left to the completion callback.
If both host and port are provided an active
connection to the data source is made. If only a port is
specified (with host the empty string) then a passive
connection is made instead, i.e. the receiver then waits for a
conneciton by the transmitter.
Any arguments after the port are treated as options and are used to
configure the internal receiver object.
See the section Options for a list of the supported options
and their meaning.
Note however that the signature of the command prefix specified
for the -command callback differs from the signature for the
same option of the receiver object.
This callback is only given the number of bytes and transfered, and
possibly an error message. No reference to the internally used
receiver object is made.
The result returned by the command is the empty string
if it was set to make an active connection, and the port the
internal receiver object is listening on otherwise, i.e when it is
configured to connect passively.
See also the package transfer::connect and the description
of the method connect for where this behaviour comes from.
-
transfer::receiver stream file path host port ? arg... ?
-
This method is like stream channel, except that the
received data is written to the file path, replacing any prior
content.
All objects created by the
::transfer::receiver command have the
following general form:
-
objectName method ? arg arg ... ?
-
The method method and its arg'uments determine the
exact behavior of the command.
See section Object methods for the detailed
specifications.
-
objectName destroy
-
This method destroys the object. Doing so while a reception is on
progress will cause errors later on, when the reception completes
and tries to access the now missing data structures of the destroyed
object.
-
objectName start
-
This method initiates the data reception, setting up the connection
first and then copying the received information into the
destination.
The method will throw an error if a reception is already/still in
progress.
I.e. it is not possible to run two receptions in parallel, only in
sequence.
Errors will also be thrown if the configuration of the data
destination is invalid, or if no completion callback was specified.
The result returned by the method is the empty string
for an object configured to make an active connection, and the port the
object is listening on otherwise, i.e when it is
configured to connect passively.
See also the package transfer::connect and the description
of the method connect for where this behaviour comes from.
-
objectName busy
-
This method returns a boolean value telling us whether a reception
is in progress (True), or not (False).
All receiver objects support the union of the options supported by
their connect and data destination components, plus one of their own.
See also the documentation for the packages
transfer::data::destination and
transfer::connect.
-
-command cmdprefix
-
This option specifies the command to invoke when the reception of
the information has been completed.
The arguments given to this command are the same as given to the
completion callback of the command transfer::copy::do provided
by the package transfer::copy.
-
-mode mode
-
This option specifies the mode the object is in. It is optional and
defaults to active mode. The two possible modes are:
- active
-
In this mode the two options -host and -port are
relevant and specify the host and TCP port the object has to connect
to. The host is given by either name or IP address.
- passive
-
In this mode the option -host has no relevance and is ignored
should it be configured.
The only option the object needs is -port, and it specifies
the TCP port on which the listening socket is opened to await the
connection from the partner.
-
-host hostname-or-ipaddr
-
This option specifies the host to connect to in active mode,
either by name or ip-address. An object configured for passive
mode ignores this option.
-
-port int
-
For active mode this option specifies the port the object is
expected to connect to. For passive mode however it is the port
where the object creates the listening socket waiting for a
connection. It defaults to 0, which allows the OS to choose
the actual port to listen on.
-
-socketcmd command
-
This option allows the user to specify which command to use to open a
socket. The default is to use the builtin ::socket. Any
compatible with that command is allowed.
The envisioned main use is the specfication of tls::socket. I.e.
this option allows the creation of secure transfer channels, without
making this package explicitly dependent on the tls package.
See also section Secure connections.
-
-encoding encodingname
-
-
-eofchar eofspec
-
-
-translation transspec
-
These options are the same as are recognized by the builtin command
fconfigure. They provide the configuration to be set for the
channel between the two partners after it has been established, but
before the callback is invoked (See method connect).
-
-channel handle
-
This option specifies that the destination of the data is a channel,
and its associated argument is the handle of the channel to write the
received data to.
-
-file path
-
This option specifies that the destination of the data is a file, and
its associated argument is the path of the file to write the received
data to.
-
-variable varname
-
This option specifies that the destination of the data is a variable,
and its associated argument contains the name of the variable to write
the received data to. The variable is assumed to be global or
namespaced, anchored at the global namespace.
-
-progress command
-
This option, if specified, defines a command to be invoked for each
chunk of bytes received, allowing the user to monitor the progress of
the reception of the data. The callback is always invoked with one
additional argument, the number of bytes received so far.
One way to secure connections made by objects of this package is to
require the package
tls and then configure the option
-socketcmd to force the use of command
tls::socket to
open the socket.
# Load and initialize tls
package require tls
tls::init -cafile /path/to/ca/cert -keyfile ...
# Create a connector with secure socket setup,
transfer::receiver R -socketcmd tls::socket ...
...
This document, and the package it describes, will undoubtedly contain
bugs and other problems.
Please report such in the category
transfer of the
http://sourceforge.net/tracker/?group_id=12883.
Please also report any ideas for enhancements you may have for either
package and/or documentation.
transfer, copy, channel, data destination, receiver, ssl, tls, secure