Groovy/FAQ/Сокеты
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Версия от 09:12, 8 декабря 2008; Root (Обсуждение | вклад)
| Groovy · |
Introduction
//---------------------------------------------------------------------------------- myClient = new Socket("Machine name", portNumber) myAddress = myClient.inetAddress myAddress.hostAddress // string representation of host address myAddress.hostName // host name myAddress.address // IP address as array of bytes //----------------------------------------------------------------------------------
Writing a TCP Client
//---------------------------------------------------------------------------------- s = new Socket("localhost", 5000); s << "Why don't you call me anymore?\n" s.close() //----------------------------------------------------------------------------------
Writing a TCP Server
//---------------------------------------------------------------------------------- // commandline socket server echoing input back to originator groovy -l 5000 -e "println line" // commandline socket server eching input to stderr groovy -l 5000 -e "System.err.println line" // a web server as a script (extension to cookbook) server = new ServerSocket(5000) while(true) { server.accept() { socket -> socket.withStreams { input, output -> // ignore input and just serve dummy content output.withWriter { writer -> writer << "HTTP/1.1 200 OK\n" writer << "Content-Type: text/html\n\n" writer << "<html><body>Hello World! It's ${new Date()}</body></html>\n" } } } } //----------------------------------------------------------------------------------
Communicating over TCP
//---------------------------------------------------------------------------------- server = new ServerSocket(5000) while(true) { server.accept() { socket -> socket.withStreams { input, output -> w = new PrintWriter(output) w << "What is your name? " w.flush() r = input.readLine() System.err.println "User responded with $r" w.close() } } } //----------------------------------------------------------------------------------
Setting Up a UDP Client
//---------------------------------------------------------------------------------- // UDP client data = "Message".getBytes("ASCII") addr = InetAddress.getByName("localhost") port = 5000 packet = new DatagramPacket(data, data.length, addr, port) socket = new DatagramSocket() socket.send(packet) //----------------------------------------------------------------------------------
Setting Up a UDP Server
//---------------------------------------------------------------------------------- // UDP server socket = new DatagramSocket(5000) buffer = (' ' * 4096) as byte[] while(true) { incoming = new DatagramPacket(buffer, buffer.length) socket.receive(incoming) s = new String(incoming.data, 0, incoming.length) String reply = "Client said: '$s'" outgoing = new DatagramPacket(reply.bytes, reply.size(), incoming.address, incoming.port); socket.send(outgoing) } // UDP client data = "Original Message".getBytes("ASCII") addr = InetAddress.getByName("localhost") port = 5000 packet = new DatagramPacket(data, data.length, addr, port) socket = new DatagramSocket() socket.send(packet) socket.setSoTimeout(30000) // block for no more than 30 seconds buffer = (' ' * 4096) as byte[] response = new DatagramPacket(buffer, buffer.length) socket.receive(response) s = new String(response.data, 0, response.length) println "Server said: '$s'" // => Server said: 'Client said: 'Original Message'' //----------------------------------------------------------------------------------
Using UNIX Domain Sockets
//---------------------------------------------------------------------------------- // DOMAIN sockets not available in cross platform form. // On Linux, use jbuds: // http://www.graphixprose.com/jbuds/ //----------------------------------------------------------------------------------
Identifying the Other End of a Socket
//---------------------------------------------------------------------------------- // TCP socket socketAddress = tcpSocket.remoteSocketAddress println "$socketAddress.address, $socketAddress.hostName, $socketAddress.port" // UDP packet println "$udpPacket.address, $udpPacket.port" //----------------------------------------------------------------------------------
Finding Your Own Name and Address
//---------------------------------------------------------------------------------- // Print the fully qualified domain name for this IP address println InetAddress.localHost.canonicalHostName //----------------------------------------------------------------------------------
Closing a Socket After Forking
//---------------------------------------------------------------------------------- socket.shutdownInput() socket.shutdownOutput() //----------------------------------------------------------------------------------
Writing Bidirectional Clients
//---------------------------------------------------------------------------------- // Spawn off a thread to handle each direction //----------------------------------------------------------------------------------
Forking Servers
//---------------------------------------------------------------------------------- // Spawn off a thread to handle each request. // This is done automatically by the Groovy accept() method on ServerSocket. // See 17.3 for an example. //----------------------------------------------------------------------------------
Pre-Forking Servers
//---------------------------------------------------------------------------------- // Use a thread pool //----------------------------------------------------------------------------------
Non-Forking Servers
//---------------------------------------------------------------------------------- // Consider using Selector and/or SocketChannel, ServerSocketChannel and DatagramChannel //----------------------------------------------------------------------------------
Writing a Multi-Homed Server
//---------------------------------------------------------------------------------- // When creating a socket on a multihomed machine, use the socket constructor with // 4 params to select a specific address from those available: socket = new Socket(remoteAddr, remotePort, localAddr, localPort) // When creating a server on a multihomed machine supply the optional bindAddr param: new ServerSocket(port, queueLength, bindAddr) //----------------------------------------------------------------------------------
Making a Daemon Server
//---------------------------------------------------------------------------------- // Fork off a thread for your server and call setDaemon(true) on the thread. //----------------------------------------------------------------------------------
Restarting a Server on Demand
//---------------------------------------------------------------------------------- // Consider using special packages designed to provide robust startup/shutdown // capability, e.g.: http://jakarta.apache.org/commons/daemon/ //----------------------------------------------------------------------------------
Program: backsniff
//---------------------------------------------------------------------------------- // Alternative to cookbook as proposed inetd solution is not cross platform. host = 'localhost' for (port in 1..1024) { try { s = new Socket(host, port) println("There is a server on port $port of $host") } catch (Exception ex) {} } // You could open a ServerSocket() on each unused port and monitor those. //----------------------------------------------------------------------------------
Program: fwdport
//---------------------------------------------------------------------------------- // It's not too hard to write a TCP Proxy in Groovy but numerous Java packages // already exist, so we might as well use one of those: // http://ws.apache.org/axis/java/user-guide.html#AppendixUsingTheAxisTCPMonitorTcpmon //----------------------------------------------------------------------------------
