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libxrx - RX Netscape Navigator Plug-in
RX Plug-in may be used with Netscape Navigator (3.0 or later) to interpret
documents in the RX MIME type format and start remote applications.
RX Plug-in reads an RX document, from which it gets the list of services
the application wants to use. Based on this information, the RX Plug-in sets
the various requested services, including creating authorization keys if
your X server supports the SECURITY extension. It then passes the relevant
data, such as the X display name, to the application through an HTTP GET
request of the associated CGI script. The Web server then executes the CGI
script to start the application. The client runs on the web server host
connected to your X server. In addition when the RX document is used within
the EMBED tag (a Netscape extension to HTML), the RX Plug-in uses the XC-APPGROUP
extension, if it is supported by your X server, to cause the remote application
to be embedded within the browser page from which it was launched.
install the RX Plug-in so that Netscape Navigator can use it, find the file
named libxrx.so.6.3 or libxrx.sl.6.3 (or similar, depending on your platform)
in <ProjectRoot>/lib (e.g. /usr/X11R6.4/lib) and copy it to either /usr/local/lib/netscape/plugins
or $HOME/.netscape/plugins. Do not install the symlinks libxrx.so or libxrx.sl;
they would confuse Netscape.
If you have configured Netscape Navigator to
use the RX helper program (xrx), you must reconfigure it. Generally you
simply need to remove or comment out the line you may have previously added
in your mailcap file to use the RX helper program. Otherwise the plug-in
will not be enabled. (The usual comment character for mailcap is ``#''.)
are already running Netscape Navigator, you need to exit and restart it
after copying the plug-in library so the new plug-in will be found. Once this
is done you can check that Navigator has successfully loaded the plug-in
by checking the ``About Plug-ins'' page from the Help menu. This should show
File name: /usr/local/lib/netscape/plugins/libxrx.sl.6.3
X Remote Activation Plug-in
Mime Type Description Suffixes Enabled
application/x-rx X Remote Activation Plug-in xrx Yes
Once correctly configured, Netscape Navigator will activate the RX Plug-in
whenever you retrieve any document of the MIME type application/x-rx.
RX Plug-in looks for resources associated with the widget netscape.Navigator
(class Netscape.TopLevelShell) and understands the following resource names
- xrxHasFirewallProxy (class XrxHasFirewallProxy)
whether an X server firewall proxy (see xfwp) is running and should be
used. Default is ``False.'' The X firewall proxy uses the X Security Extension
and this extension will only allow clients to connect to the X server if
host-based authentication is turned on. See xfwp(1)
for more information.
- xrxInternalWebServers (class XrxInternalWebServers)
- The web servers for
which the X server firewall proxy should not be used (only relevant when
xrxHasFirewallProxy is ``True''). Its value is a comma separated list of mask/value
pairs to be used to filter internal web servers, based on their address.
The mask part specifies which segments of the address are to be considered
and the value part specifies what the result should match. For instance
the following list:
matches the address sets: 198.112.45.* and 198.112.46.*. More precisely, the
test is (address & mask) == value.
- xrxFastWebServers (class XrxFastWebServers)
- The web servers for which LBX should not be used. The resource value is
a list of address mask/value pairs, as previously described.
- The web servers from which remote applications
should be run as trusted clients. The default is to run remote applications
as untrusted clients. The resource value is a list of address mask/value
pairs, as previously described.
If the RX document requests X-UI-LBX
service and the default X server does not advertise the LBX extension,
the RX Plug-in will look for the environment variable ``XREALDISPLAY'' to get
a second address for your X server and look for the LBX extension there.
When running your browser through lbxproxy you will need to set XREALDISPLAY
to the actual address of your server if you wish remote applications to
be able to use LBX across the Internet.
If the RX document requests XPRINT
service, RX Plug-in looks for the variable ``XPRINTER'' to get the printer name
and X Print server address to use. If the server address is not specified
as part of XPRINTER, RX Plug-in uses the first one specified through the
variable ``XPSERVERLIST'' when it is set. When it is not RX Plug-in then tries
to use the video server as the print server. If the printer name is not
specified via XPRINTER, RX Plug-in looks for it in the variables ``PDPRINTER'',
then ``LPDEST'', and finally ``PRINTER'',
Finally, if you are using a firewall
proxy, RX Plug-in will look for ``PROXY_MANAGER'' to get the address of your
proxy manager (see proxymngr). When not specified it will use ":6500" as
When an authorization key is created for a remote
application to use the X Print service, the RX Plug-in has to create the
key with an infinite timeout since nobody knows when the application will
actually connect to the X Print server. It then revokes the key when its
instance is destroyed (that is when you go to another page). However, if
the Plug-in does not get destroyed properly, which happens when Netscape
Navigator dies unexpectedly, the print authorization key will never get
, xfwp (1)
, lbxproxy (1)
, proxymngr (1)
, The RX
Arnaud Le Hors and Kaleb Keithley, X Consortium
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