Socket Communications in LiveCode Office of Digital Humanities Back BYU LiveCode Lessons Gateway Socket Communications in LiveCode Sockets are a way to open a direct communication channel between processes different computers or between different processor on the same computer. In learning the rudiments of socket communications, I found the following tips useful. Useful Tips On SocketsThis browser does not support iframes. Tip #1 comes from Brian Yennie, from the use-livecode email list. It gives a very basic description of how to set up a socket connection on a client and server, and so is useful as a first attempt. The second reference is from Dave Cragg, a networking expert in LiveCode. It also appeared on the use-livecode list in response to another developers questions about sockets. Dave wrote some of the networking libraries that come with LiveCode. There are several commands, functions and properties in the LiveCode scripting language for working with sockets. The readings here refer to several of them. Below is a concise listing. More information can be found in the LiveCode Dictionary. LiveCode Language Elements for inter-process communications open socket command - opens a connection to another computer close socket command - closes the connection accept command - accepts a connection request from another computer requesting a socket read from socket command - accepts data from a socket, puts the data into it write to socket command - sends data to a socket resetAll command - closes all open sockets socketError message - message that is sent when an error occurs; allows you to write a handler to handle the error + various functions and properties that allow for fine control of the communication between computers socketTimeoutInterval function - returns the timeout interval for an inactive connection openSockets function - returns a list of open sockets hostNameToAddress function - when given a host name, returns an IP address hostAddressToName function - when given an IP address, returns a host name hostAddress function - returns the IP address of a local system a socket is connected to peerAddress function - returns the IP address of the system at the other end of a socket Some example stacks You can download a pair of stacks that demonstrate the basics of socket communication. There is a client stack and a server stack. You will need two computers, one to run the client stack and another to run the server stack. Note the IP address of the server stack, and enter it into the IP address field of the client. These stacks are more experiments than finished products. I invite you to play with them, modify them and experiment as you try to master socket communications. To get the stacks, enter the following commands, one at a time, in your LiveCode message box: go stack URL "http://livecode.byu.edu/internet/socketclient.rev"
go stack URL "http://livecode.byu.edu/internet/socketServer.rev"
For a more fully-developed example of a real LiveCode application that uses socket communications, see Björnke von Gierke's excellent ChatRev stack. You can download it from inside the LiveCode environment. Make sure you have a good internet connection, then just click on the Rev Online icon on the toolbar. Then click on "All" then "Internet". Select ChatRev from the list that appears. In the right-hand panel, click Download. The stack should open and you can experiment with it. Back BYU LiveCode Lessons Gateway Maintained by Devin Asay. Copyright © 2005 Brigham Young University. This page last updated on January 06, 2020 17:20:35.
