We are using an ICE video streaming solution using GStreamer. But for some reason I can't find out how to detect if the receiver has suddenly vanished. GStreamer just keeps happily sending data to no recipient.
I already had thoughts about using webrtcbin's "connection-state" property but not sure if this will actually work if the client just quietly drops. Seems like it will just stay in connected state. Plus very unsure about the implementation.
Any help would be greatly appreciated.
I'm using VBA for Excel to communicate with hardware via serial communication. The code uses API calls similar to this here: http://dev.emcelettronica.com/serial-port-communication-in-excel-vba.
I've been successful with rs232 but it isn't working with rs485. After sending data and reading back the response, the read times out and it reads the same data that was sent.
I have access to software that someone else developed and their software works, so I know that the hardware is ok. I used a serial port sniffer and their code seems to have a lot of redundancy but it looks like its using the same configuration and sending the same data as my code. But their code gets a valid response while mine doesn't.
Could someone share some basic troubleshooting tips for this type of problem?
A major difference between rs232 and rs485 is that rs485 has an additional configuration setting for wire mode. The rs485 can support 2-wire or 4-wire configurations, with 3 different 2-wire configurations. Once I selected the correct configuration, the same code that I used for rs232 worked for rs485.
Hi I have started a project which connects to a database and creates/logs in a user at the moment i have a LAN messenger that works very well, and a FTP chat which is not exactly what i was hoping for.
my idea now is to create two tables in the database message 1 and message 2 both of which display the user who is sending and the message sent. and the program uses threading to connect and download the messages.
My question is, is there a better way of completing this task (if so could you send a link or two this way? or express your opinion).
and or any problems you guys/girls think i would run into. Cheers :D
If you require to see some code just ask and i'll edit the post thanks
Although its easy on paper to do a chat application that uses a 'DB' as a backend/comms layer .. its not really the best approach. It will work... but with load, it may not be a very good approach.
Most chat clients uses a peer to peer connection, or even client server with the coding and implementation of a server that handles what happens with messages going/destined where ever.
If you really want to get low down and dirty, google for 'TCP chat application' examples. If you want to operate a bit higher (not handle the really gritty low down mechanics), then look for some 'wcf chat' examples.
I made some code in vb.net which checks if a certain process is running, and returns a 1 if it is, or a 0 if it isn't. Now I want it to send a packet to my server or something which would log the IP of the client, or something similar.
What would be the easiest way to approach this?
There are a lot of different solutions to this task. First, which comes to my mind is WCF - maybe the easiest one as you do not think about opening ports, establishing the connections, parsing the input socket string and so on.
Here is on more link:
Introducing Windows Communication Foundation in .NET Framework 4
I'm writing a GUI-based app in VB.net that talks to a LambdaMOO server via telnet, sends commands to display the object hierarchy, then parses the output and creates a visual representation of the object hierarchy.
So my question is: is there some kind of "telnet client" class for .NET to simplify the sending and receiving of data, or do I have to write my own using the socket API?
Does Mono have something like this?
Barring an easy solution, does anyone have a good tutorial they can point to for telnet client programming in VB.net?
Ok, I had a similar issue and ignoring all security complications and the like, wanted to TELNET from a VB initiated connection to a remote device and do stuff. I concur that the whole negotiation process is a hellish thing to do but once you've worked it out it's actually pretty simple to implement. I decided not to stop because I kept reading things that said it couldn't be done when it clearly can be done if you can write and read 1's and 0's into/from a network stream.
The code in the link below will initiate the connection and get you through to actually exchanging clear text information over TELNET. Given the example of sending a username and password combo shows how to read and write to the connection.
Big tips - initially have a nice big textbox or something to trap everything that comes into the buffer (variable returndata). This will help you diagnose problems. Also check on my blog there how to do this without the textbox blinking like a flashing thing. Once you've done all that and you know your script is reliable, trun off any screen updates and it will whizz through rather than take an age.
Apologies for the really dirty code and the crappy website layout.
http://myhead-online.blogspot.com/2009/05/vb-net2008-express-telnet-to-sun.html
The telnet protocol is basically just the usual TCP protocol, with a bunch of optional stuff that you probably won't need to implement. So you'd open a socket and start sending and receiving data with the socket stream interface.
Give it a try with the regular socket API, you'll probably find that it's quite straightforward.
just a suggestion. you may try to program your vb application to execute an existing telnet application in batch mode.
here is the link for your reference. refer to 7.3 Using Plink in batch files and scripts. Hope it helps.
You can grab one of any number of libraries to use. Here's one library:
LINK
For others try googling something along the lines of: library telnet mud .NET
Lastly, there are any number of opensource MUD/MOO/MUSH projects open at any time who are willing the share ideas and looking for people to help with projects.
I had my trials with telnet. You've to use tools like wireshark in conjuntion to figure out what commands needs to be initiated. I did find communicating with my unix box quite a challenge. For one thing you must know your telnet instructions. You might find it difficult to determined the state of the application - whether it is logged in or not innately. You'd have to formulate your own logic for it.
Another thing you'd have to do is parse the bytes returned by telnet into commands or instruction data i.e. you have to know if the bytes received is an instruction or some other thing it is trying to send you. Here is a ref that would come in handy.
First I suggest you start using the wireshark tool and get the communications send to and fro manually as well as via application.
From the LambdaMOO end of things, if you have wizard access or are friends with someone who does, you can have the MOO give you the data over another protocol that you might be able to work with more readily, such as HTTP. All you need is an object on the MOO with a do_login_command() set to handle requests, and then use the listen() builtin to get that object to listen on a given port. As long as a protocol doesn't require anything complex SSL, it's fairly easy to code up on the MOO end. So that might be worthwhile if VB.net has easier handling for HTTP etc.