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<H1>The <A HREF="http://java.sun.com/">Java<SUP>(tm)</SUP></A>
Telnet Applet: Documentation</H1>
© 1996-98 <A HREF="mailto:leo@mud.de">Matthias L. Jugel</A>,
<A HREF="mailto:marcus@mud.de">Marcus Meißner</A>
<HR>
<P>
The package contains several parts of which the most important one is the
<B>Telnet Applet/Application</B>. Select from the list below what you
are interested in. If you only want to use the applet choose <A
HREF="#SetupTelnet">Telnet</A> from <B>Setup</B> and if you want to use the
<A HREF="Source/packages.html">packages</A> in your own programming, select the
appropriate from <B>Source Code</B>.
<H3 ALIGN=CENTER><A HREF="#Readme">READ THIS FIRST</A></H3>
<H3 ALIGN=CENTER><A HREF="#SetupDoc">Setup</A></H3>
<P ALIGN=CENTER>
<B>[
<A HREF="#SetupTelnet">Telnet</A> |
<A HREF="#SetupTerminal">Terminal Emulation</A> |
<A HREF="#SetupModules">Modules</A>
]<BR>[
<A HREF="#SetupAppWrapper">Applet Wrapper</A> |
<A HREF="#SetupProxy">Proxy Server</A>
]</B>
<H3 ALIGN=CENTER><A HREF="#SourceDoc">Source Code</A></H3>
<P ALIGN=CENTER>
<B>[
<A HREF="Source/telnet.html">Telnet</A> |
<A HREF="#SourceTerminal">Terminal Emulation</A> |
<A HREF="#SourceModules">Modules</A>
]<BR>[
<A HREF="Source/appWrapper.html">Applet Wrapper</A> |
<A HREF="Source/proxy.html">Proxy Server</A>
]<BR>[
<A HREF="Source/packages.html">Packages</A> |
<A HREF="Source/AllNames.html">Field and Method Index</A> |
<A HREF="Source/tree.html">Class Tree</A>
]</B>
<P>
<A HREF="../index.html">
<IMG SRC="images/left.gif" BORDER=0 ALT="[BACK]"></A>
<B>Get the <A HREF="http://www.first.gmd.de/persons/leo/java/Telnet">latest
version</A> here!</B>
<HR>
<A NAME="Readme"></A>
<H1>READ THIS FIRST</H1>
We found that some people have no knowlegde whatsoever of java and its
restrictions. We have compiled a few questions and answers here as well
as some reasons why you should or should not use
<B>The Java<SUP>(tm)</SUP> Telnet Applet</B>:
<DL>
<DT><B>Some web page told me I need telnet, is this it?</B>
<DD>Yes and No! The Applet is a fully featured Telnet and Terminal
emulator, but usually you're better off using the program that
comes with your system. Most of the UNIX based systems have very
good terminal emulators (xterm) and alway have a telnet
application. Windows 95 comes with a telnet if you have the network
stuff installed it's there: c:\windows\telnet.exe. It should be
sufficient. If you want better terminal emulation and <I>colours</I>
the better choice is <B>The Java<SUP>(tm)</SUP> Telnet Applet</B>!
<P>
<DT><B>I cannot connect to some.where.com? It only says
"Trying some.where.com ..."</B>
<DD>A Java applet is restricted in several ways. One of the restrictions
is that it may <I>only</I> connect to the web server where it was
downloaded from! So if you put the applet on <I>www.where.com</I> but
set the "address" field to <I>some.where.com</I> you
won't get a connection. Read about our
<A HREF="#SetupProxy">relayd daemons</A>!
<P>
<DT><B>But I loaded the HTML file from my harddisk and it still does
not work!</B>
<DD>Netscape and Internet Explorer do not accept your hard disk as
secure space. So they will prevent the applet from accessing any
resource, such as the network. You may overcome that by adding the
directory where the applet is stored to your "CLASSPATH"
environment variable <I>before</I> running the browser.
<P>
</DL>
<HR>
<A NAME="SetupDoc"></A>
<H1>Setup Documentation</H1>
<A NAME="SetupTelnet"></A>
<H2>How to setup the Telnet Applet</H2>
Make sure, you got the
<A HREF="http://www.first.gmd.de/persons/leo/java/Telnet">latest version</A>
of the Java<SUP>(tm)</SUP> Telnet Applet. Refer to the
<A HREF="http://www.first.gmd.de/persons/leo/java/Telnet/index.download.html">
download page</A> on how to get it and how to
extract the files from the archive. After successfully extracting the complete
package you should have a directory <B>Telnet/</B> containing <B>*.html</B>,
<B>*.java</B> and <B>*.class</B> files as well as the directores
<B>Documentation/</B>, <B>display/</B>, <B>modules/</B>, <B>socket/</B> and
<B>tools</B>.<P>
To install the applet on your web page you need as least the following files
and directories. Make sure that all files and directories are <B>readable
by other users</B>!
<PRE>
index.test.html
telnet.class
appWrapper.class
display/
display/SoftFont.class
display/CharDisplay.class
display/Terminal.class
display/TerminalHost.class
display/vt320.class
socket/
socket/TelnetIO.class
socket/StatusPeer.class
modules/
modules/Module.class
modules/Script.class
modules/ButtonBar.class
modules/MudConnector.class
</PRE>
Now edit <B>index.test.html</B> to adapt it to your needs or look at the
example below! The file is documented and if you have questions about
the <I>Modules</I> refer to the
<A HREF="#SetupModules">Module Documentation</A> or look at the <A
HREF="Source/Package-modules.html">Source Code</A>. You will find, that not
<B>telnet.class</B> is loaded as applet, but <B>appWrapper.class</B> instead.
This is necessary to enable the <B>detach</B> feature!
<P>
<DL>
<DT><B><I>Important Note:</I></B>
<DD>We would appreciate to see <B>credits</B> on a page using the applet
which includes a link to the <I>
<A HREF="http://www.first.gmd.de/persons/leo/java/Telnet">applets home
page</A></I> and names of the <I>authors</I> as mentioned on
<A HREF="#TOP">top</A> of this page. You may simply use our
<A HREF="../index.test.html">test page</A> and edit it to your needs.<BR>
In response we will include a link to your page on our
<I><A HREF="user.html">user page</A></I>, if you like.
</DL>
<P>
The telnet applet can be customized using the following parameters:
<PRE>
<PARAM NAME=address VALUE="tanis.first.gmd.de">
<PARAM NAME=port VALUE="23">
<PARAM NAME=emulation VALUE="vt320">
<PARAM NAME=proxy VALUE="www.first.gmd.de">
<PARAM NAME=proxyport VALUE="31415">
</PRE>
The <B><I>proxy</I></B> and <B><I>proxyport</I></B> parameters may be left
out. They are needed if your target host is NOT the same as your web server
and you are using the <A HREF="#mrelayd">relay daemon</A>.
<P>
<A NAME="Example_1"></A>
<H3>Example:</H3>
(all possible parameters)
<PRE>
<APPLET CODE="<A HREF="Source/appWrapper.html">appWrapper.class</A>" WIDTH=600 HEIGHT=480>
<!-- appWrapper parameters -->
<PARAM NAME="applet" VALUE="<A HREF="Source/telnet.html">telnet</A>">
<!-- optional (WIDTH and HEIGHT should be changed!) -->
<PARAM NAME="startButton" VALUE="Connect to www.first.gmd.de!">
<PARAM NAME="stopButton" VALUE="Shutdown telnet!">
<PARAM NAME="frameTitle" VALUE="The Java Telnet Applet: WWW">
<!-- applet parameters: address and port and emulation -->
<PARAM NAME="address" VALUE="www.first.gmd.de">
<PARAM NAME="port" VALUE="23">
<PARAM NAME="emulation" VALUE="vt320">
<!-- terminal emulation parameters (optional)-->
<PARAM NAME="VTscrollbar" VALUE="true">
<PARAM NAME="VTresize" VALUE="font">
<PARAM NAME="VTfont" VALUE="Courier">
<PARAM NAME="VTfontsize" VALUE="13">
<PARAM NAME="VTid" VALUE="vt220">
<PARAM NAME="VTcharset" VALUE="ibm">
<!-- module parameters: #1 is a buttonbar (optional) -->
<PARAM NAME="module#1" VALUE="<A HREF="#ButtonBar">ButtonBar</A>@North">
<PARAM NAME="1#Button" VALUE="connect|\$connect()">
<PARAM NAME="2#Button" VALUE="disconnect|\$disconnect()">
<PARAM NAME="3#Button" VALUE="Detach/Delete Window|\$detach()">
<PARAM NAME="4#Button" VALUE="Send:|\@send@\r\n">
<PARAM NAME="5#Input" VALUE="send#10|who">
<!-- module parameter: #2 is a scripting module (optional) -->
<PARAM NAME="module#2" VALUE="<A HREF="#Script">Script</A>">
<PARAM NAME="script" VALUE="login:|leo">
<!-- make sure, non-java-capable browser get a message: -->
<B>
Your Browser seems to have no <A HREF="http://java.sun.com/">Java</A>
support. Please get a new browser or enable Java to see this applet!
</B>
</APPLET>
</PRE>
<P>
<HR>
<A NAME="SetupTerminal"></A>
<H2>Setting up the Terminal Emulation</H2>
The Terminal Emulation is a very important part of the Telnet Applet, because
it enables you to use programs that make use of certain features of hardware
terminals like <B>VT100</B> or <B>ANSI</B>. Supplied with the package is an
almost <B>VT320 compliant</B> terminal emulation, that should include the two
mentioned earlier. This means that the applet can do colors, even if the
original <B>VT320</B> terminal cannot!<P>
The applet supports the <B><I>special graphical character set</I></B> of VT
terminals. The new implementation supports all graphical characters with a
small drawback. The more graphical characters on the screen the slower is the
display. We will remove the current implementation when full UNICODE support
is available from all browsers (full JDK 1.2 compatibility).
<P>
To configure the terminal emulation look at the list of parameters below:<BR>
<I>Note:</I> Default values are typeset in <I>italics</I> and other possible
values in <B>bold</B>.
<DL>
<DT><TT><B><PARAM NAME="VTcolumns" VALUE="<I>80</I>"></B></TT>
<DD>Sets the columns of the terminal initially. If the parameter
VTresize is set to <B>screen</B> this may change, else it is fixed.
<DT><B><TT><PARAM NAME="VTrows" VALUE="<I>24</I>"></TT></B>
<DD>Sets the rows of the terminal initially. If the parameter
value of VTresize <B>screen</B> this may change!
<DT><B><TT><PARAM NAME="VTfont" VALUE="<I>Courier</I>"></TT></B>
<DD>Sets the font to be used for the terminal. It is recommended to
use <I>Courier</I> or at least a fixed width font.
<DT><B><TT><PARAM NAME="VTfontsize" VALUE="<I>14</I>"></TT></B>
<DD>Sets the font size for the terminal. If the parameter
value of VTresize is set to <B>font</B> this may change!
<DT><B><TT><PARAM NAME="VTresize" VALUE="<I>font</I>"></TT></B>
<DD>This parameter determines what the terminal should do if the window
is resized. The default setting <I><B>font</B></I> will result in
resizing the font until is matches the window best. Other possible
values are <B>none</B> or <B>screen</B>. <B>none</B> will let nothing
happen and <B>screen</B> will let the display try to change the
amount of rows and columns to match the window best.
<DT><B><TT><PARAM NAME="VTscrollbar" VALUE="<I>false</I>"></TT></B>
<DD>Setting this parameter to <B>true</B> will add a scrollbar west to
the terminal. Other possible values include <B>left</B> to put the
scrollbar on the left side of the terminal and <B>right</B> to put it
explicitely to the right side.
<DT><B><TT><PARAM NAME="VTid" VALUE="<I>vt320</I>"></TT></B>
<DD>This parameter will override the terminal id <I>vt320</I>. It may
be used to determine special terminal abilities of VT Terminals.
<DT><B><TT><PARAM NAME="VTbuffer" VALUE="<I>xx</I>"></TT></B>
<DD>Initially this parameter is the same as the VTrows parameter. It
cannot be less than the amount of rows on the display. It determines
the available scrollback buffer.
<DT><B><TT><PARAM NAME="VTcharset" VALUE="<I>none</I>"></TT></B>
<DD>Setting this parameter to <B>ibm</B> will enable mapping of ibm
characters (as used in PC BBS systems) to UNICODE characters. Note
that those special characters probably won't show on UNIX systems
due to lack in X11 UNICODE support.
<DT><B><TT><PARAM NAME="VTvms" VALUE="<I>false</I>"></TT></B>
<DD>Setting this parameter to <B>true</B> will change the Backspace key
into a delete key, cause the numeric keypad keys to emit VT100
codes when Ctrl is pressed, and make other VMS-important keyboard
definitions.
<DT><B><TT><PARAM NAME="F<I>nr</I>" VALUE="<I>string</I>"></TT></B>
<DD>Function keys from <I>F1</I> to <I>F20</I> are programmable. You can
install any possible string including special characters, such as
<TABLE BORDER>
<TR><TD><TT>\e</TT></TD><TD>Escape</TD><TD></TD>
<TD><TT>\b</TT></TD><TD>Backspace</TD><TD></TD>
<TD><TT>\n</TT></TD><TD>Newline</TD><TD></TD>
<TD><TT>\r</TT></TD><TD>Return</TD>
</TABLE>
</DL>
<P>
Please look at the <A HREF="#Example_1">example above</A>.
<P>
<HR>
<A NAME="SetupModules"></A>
<H2>Setting up Modules</H2>
Another feature of the Java<SUP>(tm)</SUP> Telnet Applet is the ability to
dynamically load <B>modules</B>. A module is a java class that is loaded
after the applet has been initialized and may be used to <I>enhance</I> the
user interface or to background work in some way.<P>
To load a module a special parameter has to be added to the applet PARAM tags:
<P>
<TT><B><PARAM NAME=module#<I>number</I> VALUE="<I>modulename</I>@<I>direction</I>"></B>
</TT>
<UL>
<LI><B><I>number</I></B> is a sequence number, used by the applet to
determine the modules. Numbers must be adjacent or modules may not
be loaded.
<LI><B><I>modulename</I></B> is the name of the modules to be
loaded. Modules already in the package are described below.
<LI><B>@<I>direction</I></B> is the position of the applet in relation to
the window. Possible values are: <B>North, South, East, West</B>. The
module will then be placed accordingly. It is <I>not</I> possible to
place two modules at the same position! <I>The positional parameter may
be left out and the module will then be placed <B>North</B></I>.
</UL>
<P>
At the moment the package features three modules:
<DL>
<DT><A HREF="#ButtonBar"><B>ButtonBar</B></A>
<DD>The ButtonBar is a modules to enhance the user interface. Using
PARAM tags <B>buttons</B> and <B>input fields</B> can be added to
send text to the remote host or to <B>detach</B> the applet.<P>
<DT><A HREF="#Script"><B>Script</B></A>
<DD>Sometimes it is useful to have simple script abilities. This module
<B>executes a script</B> based on text received from the remote host.
<P>
<DT><A HREF="#MudConnector"><B>MudConnector</B></A>
<DD>This module is a special program for the <A
HREF="http://www.mudconnect.com">Mud Connector</A> by Andrew Cowan. It
loads a list of muds and displays information like host and port.
</DL>
<P>
<A NAME="ButtonBar"></A>
<H3>The ButtonBar</H3>
The ButtonBar may be used to add <A HREF="#buttons">buttons</A> to the applet
that execute functions or simply send a specified text to the remote host.
In addition it is possible to specify <A HREF="#fields">input
fields</A> as external input means.<P>
To load the module include the following tag into the <B>.html</B> file
(example):<P>
<TT><B><PARAM NAME=module#<I>1</I> VALUE="<I>ButtonBar</I>"></B>
</TT><P>
Below is a description of possible PARAM tags and a description of supported
functions:
<DL>
<DT><A NAME="buttons"></A><B>Buttons:</B>
<DD><TT><PARAM NAME=<B><I>number</I></B>#Button VALUE="<B><I>buttontext</I></B>|<B><I>buttonaction</I></B>"></TT>
<DD><B><I>number</I></B> is the sequence number and determines the place
of the button on the row.
<P>
<DD><B><I>buttontext</I></B> is a string displayed on the button.
<P>
<DD><A NAME="buttonaction"><B><I>buttonaction</I></B></A> may be one
of the following functions or strings<BR>
<FONT SIZE=-1>(<I>Note:</I> the backslash character
in front of the dollar sign is mandatory!)</FONT>
<UL>
<LI><TT><I>simple text</I></TT>
to be sent to the remote host. Newline and/or carriage return
characters may be added in C syntax <B>\n</B> and <B>\r</B>.
To support unimplemented function keys the <B>\e</B> escape
character may be useful. The <B>\b</B> backspace character is
also supported.
The text may contain <A HREF="#fieldreference"><B><I>field
reference(s)</I></B></A>.<BR>
<P>
<LI><TT>\$connect(<B><I>host</I></B>[,<B><I>port</I></B>])</TT>
tries to initiate a connection to the <B><I>host</I></B>
at the <B><I>port</I></B>, if given. The standard port is
23. <B><I>host</I></B> and <B><I>port</I></B> may be hostname
and number or <A HREF="#fieldreference"><B><I>field
reference(s)</I></B></A>. If a connection already exists
nothing will happen.<BR>
<FONT SIZE=-1>(<I>Note:</I> It is not allowed to have
spaces anywhere inside the parenthesis!)</FONT>
<P>
<LI><TT>\$disconnect()</TT>
terminates the current connection, but if there was no
connection nothing will happen.
<P>
<LI><A NAME="detach"><TT>\$detach()</TT></A>
detaches the applet from the web browser window and
creates a new frame externally. This may be used to allow
users to use the applet while browsing the web with the
same browser window.<BR>
<FONT SIZE=-1>(<I>Note:</I> You need to load the applet via the
<A HREF="#SetupAppWrapper">Applet Wrapper</A> or
it will not work properly!)</FONT>
</UL>
<P>
<DD><A NAME="Example_2"><B>Examples:</B></A><BR>
<FONT SIZE=-1>(<I>Note:</I> It makes sense if you look at the
examples for <A HREF="#Example_3">input fields</A> below.)</FONT>
<PRE>
<PARAM NAME=1#Button VALUE="HELP!|help\r\n">
<PARAM NAME=2#Button VALUE="HELP:|help \@help@\r\n">
<PARAM NAME=4#Button VALUE="simple|\$connect(localhost)">
<PARAM NAME=5#Button VALUE="complete|\$connect(www,4711)">
<PARAM NAME=6#Button VALUE="connect|\$connect(\@address@)">
<PARAM NAME=8#Button VALUE="connect to port|\$connect(\@address@,\@port@)">
<PARAM NAME=10#Button VALUE="window|\$detach()">
</PRE>
<P>
<A NAME="fields"></A>
<DT><B>Input fields</B>
<DD><TT><PARAM NAME=<B><I>number</I></B>#Input VALUE="<B><I>fieldname</I></B>[#<I><B>length</B></I>]|<B><I>initial text</I></B>[|<B><I>action</I></B>]"></TT>
<DD><B><I>number</I></B> is the sequence number and determines the place
of the field on the row.
<P>
<DD><A NAME="fieldreference"><B><I>fieldname</I></B></A> is a
symbolic name to reference the input field. A reference may be used in
<A HREF="#buttonaction"><B><I>button actions</I></B></A> and
is constructed as follows:
<TT>\@<B><I>fieldname</I></B>@</TT>
The <B>\@fieldname@</B> macro will be replaced by the string entered in
the text field.
<P>
<DD><B><I>length</I></B> is the length of the input field in numbers of
characters.
<P>
<DD><B><I>initial text</I></B> is the text to be placed into the input
field on startup
<P>
<DD><B><I>action</I></B> may be used similar to a
<A HREF="#buttonaction"><B><I>button action</I></B></A>. This action
will be used if the users presses Return in the inputfield. Leave
empty if you only want to use a button to send the text!
<P>
<DD><A NAME="Example_3"><B>Examples:</B></A><BR>
<FONT SIZE=-1>(<I>Note:</I> It makes sense if you look at the
examples for <A HREF="#Example_2">buttons</A> before.)</FONT>
<PRE>
<PARAM NAME=3#Input VALUE="help#10|">
<PARAM NAME=7#Input VALUE="address|www.first.gmd.de">
<PARAM NAME=9#Input VALUE="port#5|4711">
</PRE>
<P>
</DL>
<A NAME="Script"></A>
<H3>The Script Module</H3>
The script module gives a very simple implementation of an <I>input
triggered</I> script executor. This means it sends text to the remote host
when the received text matches a <I>pattern</I> that can be programmed. It
executes each <I>pair of pattern and text</I> only once and stops working
after all patterns have been matched. It will start working again upon a
new connection.
<P>
To load the module include the following tag into the <B>.html</B> file
(example):<P>
<TT><B><PARAM NAME=module#<I>1</I> VALUE="<I>Script</I>"></B>
</TT><P>
Below is a description of possible PARAM tags and a description of script:
<DL>
<DT><B>Scripts:</B>
<DD><TT><PARAM NAME=script VALUE="<B><I>pattern</I></B>|<B><I>text</I></B>|<B><I>...</I></B>"></TT>
<DD>A script contains of pairs of <I>pattern</I> and <I>text</I> strings.
If the pattern is matched against the output from the remote host,
the corresponding text will be sent. Each pattern will match only
<B>once</B> per connected session.
Thus it is possible to program an autologin as follows:<BR>
<TT><B>"login:|leo|Password:|mypassword|leo@www|ls"</B></TT>
Newlines will be added automatically to the string sent! At the
moment the order of the pattern and text pairs is <I>not</I> relevant.
<P>
It is possible to prompt the user for input if a match occurs. If the
corresponding <I>text</I> is a string enclosed in braces ([] or {}) a
dialog window is opened with <I>text</I> as prompt. A special case
is an empty prompt in which case the <I>pattern</I> will be shown as
prompt. "[Your name:]" would open a dialog window with the
text "Your name" as prompt. Curly braces have a special
meaning; any user input will be shown as "*" which makes
it possible to program password prompts. Example:
"{Your password:}".<P>
A special match like: "login:|[]" can be used to open a
dialog and display "login:" as prompt. This works for
"{}" as well.
</DL>
<P>
<A NAME="MudConnector"></A>
<H3>MudConnector</H3>
This module is a special edition for the <A
HREF="http://www.mudconnect.com/">Mud Connector</A>. It features a list of
MUDs and a few buttons to connect, disconnect and get infos about the MUDs.
A very nice example for a specialized module.
To load the module include the following tag into the <B>.html</B> file
(example):<P>
<TT><B><PARAM NAME=module#<I>1</I> VALUE="<I>MudConnector</I>"></B>
</TT>
The MudConnector expects the following PARAM tags:
<DL>
<DT><B>Mudlist URL:</B>
<DD><TT><PARAM NAME=mudlist VALUE="<B><I>URL</I></B>"></TT>
<DD>The URL should be a file containing line by line the <I>MUD name</I>, the
<I>Mud address</I> and the <I>MUD port</I>, separated by tabulators.
The first line in the file should be the number of MUDs in the file.
<P>
<DD><B>Example:</B><BR>
<TT><PARAM NAME=mudlist VALUE="http://www.mud.de/~leo/mudlist.data"></TT>
<P>
</DL>
<P>
<HR>
<A NAME="SetupAppWrapper"></A>
<H2>The Applet Wrapper Setup</H2>
The applet wrapper is an applet that does nothing else than loading the, for
example, telnet applet. To understand why this is necessary you have to look
at the experiences we have made.<P>
Simply using the telnet applet in the following manner:<P>
<TT><APPLET CODE="telnet.class" WIDTH=600 HEIGHT=480></TT>
and using the <A HREF="#detach">detach</A> function stops the applet after
you have detached the applet and want to browse the web again. It seems that
the Web browser stops all threads connected to the applet if you leave the
page where the applet is located and thus it doesn't even update its display
anymore.<P>
We have found out that this is not true for applets loaded within the applet
on the page (e.g. the appWrapper). Look at the following description on how
to setup the appWrapper. It will probably work with any given applet out on
the web!
<P>
<PRE>
<APPLET CODE="appWrapper.class" WIDTH=600 HEIGHT=480>
<PARAM NAME=applet VALUE="<I>telnet</I>>
<!-- optional (WIDTH and HEIGHT should be changed!) -->
<PARAM NAME=startButton VALUE="<I>text</I>">
<PARAM NAME=stopButton VALUE="<I>text</I>">
<PARAM NAME=frameTitle VALUE="<I>text</I>">
<!-- all other telnet applet parameters go here -->
</APPLET>
</PRE>
The <B>appWrapper</B> knows only about the PARAM tag <B>applet</B>, which is
the applet to be loaded. In this case it must be in the same directory as the
<B>appWrapper.class</B>. Refer to the <A HREF="#Example_1">telnet example</A>
above for the telnet parameters.<P>
If a <B>startButton</B> is specified the applet won't start automatically,
but instead the appWrapper will display a button with the <I>text</I> on
it. The <B>stopButton</B> defines the text that appears on the button when
the applet is loaded and running and <B>frameTitle</B> specifies the frame
title text of the window the applet runs in.
<P>
<HR>
<A NAME="SetupProxy"></A>
<H2>Setting up the proxy server</H2>
There are two proxy servers provided with the telnet applet. The first one
is written in java and does support connections to <B>one</B> target host only
and the second one is written in C and supports different targets (called
relay daemon).<P>
<H4 ALIGN=CENTER>
[<A HREF="#javaproxy">Java Proxy</A> |
<A HREF="#relayd">Simple Relay Daemon</A> |
<A HREF="#mrelayd">Relay Daemon</A>]
</H4>
<P>
<A NAME="javaproxy"></A>
<H3>The Java Proxy Server</H3>
The proxy server is a small java program
to overcome the security restrictions of java capable web browsers.<P>
The proxy is used to redirect a connection to a given
host. Usually an applet can only connect to the web server it has
been loaded from. Installing the proxy on your web server allows the
applet to connect to a host you would like to connect to.<P>
<DL>
<DT><B>How to run the proxy application?</B>
<DD>To run the proxy you require the following:
<OL>
<LI>A java interpreter (usually included in the JDK)
<LI>A compiled version of the proxy
(<A HREF="tools/proxy.class">proxy.class</A>)
</OL><P>
On the <I>WWW-Server command line</I> run the proxy server as follows:
<TT>java proxy 9999 remotehostname 23
</TT>
This lets the proxy listen on port 9999 and it redirects
all connections to the host "remotehostname" at port 23. You
can leave the port parameter out if it is 23 (telnet port).
<P>
The proxy should start with something like the output below:
<TT>
proxy: destination host is remotehostname at port 23
proxy: listening on port 9999
</TT>
Upon successful connection the output should produce something
like this:
<TT>
proxy: accepted connection from augra.first.gmd.de
proxy: connecting www.first.gmd.de <-> remotehostname
</TT>
<DT><B>How to shut down the proxy?</B>
<DD>To shut down the proxy press ^C (Ctrl+C or Strg+C on a german
keyboard) if you have startet it normally. More advanced users
will run the proxy like
<TT>java proxy 9999 remotehost 23 >& errorlog &</TT>
to put it into the background. The "errorlog" file should then
contain any messages. You can kill that process by looking for
the process id (ps | grep proxy) and issuing the kill
<processid> command (this applies to UNIX only).
<P>
<DT><B>I get an error message like "class proxy not found"!</B>
<DD>You may have to set the CLASSPATH environment variable to
point to the current directory or to the directory where
proxy.class is located.
</DL>
<P>
<A NAME="relayd"></A>
<H3>The Simple Relay Daemon</H3>
The <I>simple</I> relay daemon works just like the
<A HREF="#javaproxy">proxy</A> above, but is a C version. It allows
connections only to a specified host and port which is preferrable for
security reasons. You can run the program (after compiling it) with the
following command line:
<TT>
relayd serverport targethost targetport
or just
relayd serverport targethost
</TT>
It will then listen on the <I>serverport</I> of the machine you started it and
connect to the <I>targethost</I>. The standard <I>targetport</I> is 23.
<P>
<A NAME="mrelayd"></A>
<H3>The Relay Daemon</H3>
The relay daemon is a program written by Marcus Meißner to support
different target hosts. It relays the connections from the applet to a
host that must be given to the relay daemon after connecting.<P>
The daemon expects a string
<TT>relay <I>address port</I></TT>
It must be run on the web server of the applet.
The relay daemon is not included in compiled form, because we would have to
support a number of platforms. However, you can write to us if you need a
special compiled version for your hardware platform.<P>
You should include the following tags to tell <A
HREF="#SetupTelnet">telnet</A> that it is supposed to use the prox server
<PRE>
<PARAM NAME=proxy VALUE="www.first.gmd.de">
<PARAM NAME=proxyport VALUE="31415">
</PRE>
<HR>
<A NAME="SourceDoc"></A>
<H1>Source Code Documentation</H1>
The Source Code of <B>The Java<SUP>(tm)</SUP> Telnet Applet</B> is available
under the terms of the <A HREF="http://www.fsf.org/copyleft/gpl.html"><B>GNU
General Public License</B></A> as documented in the file <A
HREF="../COPYING">COPYING</A>. In case you would like to use the packages as
libraries please apply the <A HREF="http://www.fsf.org/copyleft/lgpl.html"><B>
GNU Library General Public License</B></A> as documented in the file <A
HREF="../COPYING.LIB">COPYING.LIB</A>.<P>
Select from the structure below, what you would like to see. Each file
contains a <B>Version:</B> field determining its current status and version.
If you are not sure to have the most current version, please
<A HREF="http://www.first.gmd.de/persons/leo/java/Telnet/index.download.html">
look here</A>.<P>
If you are unsure, whether you've got the newest version, compare your
copy of the file <A HREF="../REVISION"><B>REVISION</B></A> and this
<A HREF="http://www.first.gmd.de/persons/leo/java/Telnet/REVISION">
<B>REVISION</B></A>, which is a direct link to the
<A HREF="http://www.first.gmd.de/persons/leo/java/Telnet/">home page</A>.
The latest changes are documented in the file
<A HREF="../CHANGES"><B>CHANGES</B></A>.
<UL>
<LI><A HREF="Source/appWrapper.html">appWrapper.java</A>
<LI><A HREF="Source/telnet.html">telnet.java</A>
<UL>
<LI><A HREF="Source/Package-socket.html">Socket Package</A>
<UL>
<LI><A HREF="Source/socket.TelnetIO.html">socket/TelnetIO.java</A>
<LI><A HREF="Source/socket.StatusPeer.html">socket/StatusPeer.java</A>
</UL>
<LI><A NAME="SourceTerminal"></A>
<A HREF="Source/Package-display.html">Display Package</A>
<UL>
<LI><A HREF="Source/display.CharDisplay.html">display/CharDisplay.java</A>
<LI><A HREF="Source/display.SoftFont.html">display/SoftFont.java</A>
<LI><A HREF="Source/display.Terminal.html">display/Terminal.java</A>
<LI><A HREF="Source/display.TerminalHost.html">display/TerminalHost.java</A>
<LI><A HREF="Source/display.vt320.html">display/vt320.java</A>
</UL>
<LI><A NAME="SourceModules"></A>
<A HREF="Source/Package-modules.html">Module Package</A>
<UL>
<LI><A HREF="Source/modules.Module.html">modules/Module.java</A>
<LI><A HREF="Source/modules.ButtonBar.html">modules/ButtonBar.java</A>
<LI><A HREF="Source/modules.Script.html">modules/Script.java</A>
<LI><A HREF="Source/modules.MudConnector.html">modules/MudConnector.java</A>
</UL>
</UL>
<LI><A HREF="Source/IOtest.html">IOtest.java</A>
<LI><A HREF="Source/CharDisplayTest.html">CharDisplayTest.html</A>
<LI>Tools
<UL>
<LI><A HREF="Source/proxy.html">tools/proxy</A>
<LI><A HREF="Source/redirector.html">tools/redirector</A> (proxy.java)
<LI><A HREF="../tools/relayd.c">tools/relayd.c</A> (simple proxy)
<LI><A HREF="../tools/mrelayd.c">tools/mrelayd.c</A> (enhanced proxy)
</UL>
</UL>
<HR>
<A HREF="../index.html">
<IMG ALIGN=LEFT SRC="images/left.gif" BORDER=0 ALT="[BACK]"></A>
<B>Get the <A HREF="http://www.first.gmd.de/persons/leo/java/Telnet">latest
version</A> here!</B> <BR>
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