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How to encapsulate this ?

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Old 11-14-2006
How to encapsulate this ?
Hello !

I have a pretty question.I am working on a client-server chat aplication for Linux shell's.

When a user connect , is receives a window for the username . It has to enter the username, which will be used for future chat and private message ( + other option's ). I'm using socket's for network connection.

The point is , after a user is connect to server socket , the user has to enter a username . The problem here comes like that. Where does the chat server knew , if the username string is an ordinary string , used for chat , or the username string itself ?

I figure to do , some easy encaspulation.When the client connect , and receive username window , the username string is encapsulated with , let's say "***" at the end .

Let's say user !_30 is connected . First the client sends "!_30***" to server , the server dencapsulate those 3 '***' , and knows client username.

The problem here is that , when a user accidentaly send's "***" in main chat , whole sistem is doomed . The server sees "***" at the end .. of ( nothing ) and think's a new user is connected to the server.

How can I make this encapsulation/dencapsulation , transparent to send proces , not altering the string , and be doomed like up ..?

Any idea's , raw socket's ? Because the idea I mention is the only one that came , in that moment in my head .


Any ideas , is apreciate ! Cheer's ! Smilie
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LEARN ABOUT DEBIAN

drawterm

DRAWTERM(1)						      General Commands Manual						       DRAWTERM(1)

NAME

       drawterm - connect to Plan 9 CPU servers from other operating systems

SYNOPSIS

       drawterm [-d] [-a authserver] [-c cpuserver] [-e encription_hash_algs] [-k keyspec] [-s secstoreserver] [-u username] [-C command args ...]

DESCRIPTION

       drawterm  is not a Plan 9 program.  It is a program that users of non-Plan 9 systems can use to establish graphical cpu(1) connections with
       Plan 9 CPU servers.  Just as a real Plan 9 terminal does, a drawterm serves its local name space as well as  some  devices  (the  keyboard,
       mouse,  and  screen) to a remote CPU server, which mounts this name space on /mnt/term and starts a shell.  Typically, either explicitly or
       via the profile, one uses the shell to start rio(1).

       By default, drawterm uses the CPU server $cpu or cpu, and the authentication server $auth or auth,

OPTIONS

       This program follows the syntax of the cpu(1) Plan 9 command.

       A summary of options is included below.

       -h     Show summary of options.

       -a     Specifies the authentication server to use. If not present uses the $auth environment variable, if present, or  tries  with  a  host
	      name of auth.

       -c     Specifies the cpu server to use. If not present uses the $cpu environment variable, if present, or tries with a host name of cpu.

       -u     Specifies  the  username to authenticate with. If not present uses the $USER environment variable, if present, or asks interactively
	      for an username.

       -s     Specifies the secstore server to use.

       -C     Specifies a command to be executed remotely.

       -e,-k  Allow for selecting the hash algorithm and keys used, they have the same meaning as in cpu(1).

SOURCE

       In Plan 9 distributions, /sys/src/cmd/unix/drawterm.

DIAGNOSTICS

       Drawterm prints most diagnostics in its own window.

BUGS

       Although at first drawterm may seem like a Plan 9 terminal, in fact it is just a way to provide a CPU server with  some	terminal  devices.
       The  difference	is important because one cannot run terminal-resident programs when using drawterm.  The illusion can be improved by deli-
       cate adjustments in /usr/$user/lib/profile.

       Should import latest /dev/draw to allow resize of window

       Should copy 9term code and make console window a real 9term window instead.

       Should implement /dev/label.

SEE ALSO

       cpu(1), rio(1) in the Plan 9 documentation

AUTHOR

       drawterm was written by Russ Cox <rsc@swtch.com>.

       This manual page was written by Russ Cox <rsc@swtch.com>, with modifications by Martin Ferrari <tincho@debian.org> for the Debian project.

								 October 16, 2008						       DRAWTERM(1)