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<html><!-- #BeginTemplate "/Templates/tmpl.dwt" --><head><!-- #BeginEditable "doctitle" --> <title>PTypes: networking: examples</title><!-- #EndEditable --> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link rel="stylesheet" href="styles.css"></head><body bgcolor="#FFFFFF" leftmargin="40" marginwidth="40"><p><a href="../index.html"><img src="title-1.7.gif" width="213" height="34" alt="C++ Portable Types Library (PTypes) Version 1.7" border="0"></a> <hr noshade><!-- #BeginEditable "body" --> <p class="hpath"><a href="index.html">Top</a>: <a href="inet.html">Networking</a>: Examples</p><p> <b>Example 1</b>. This example demonstrates the basic usage of streaming network interfaces <span class="lang">ipstream</span> and <span class="lang">ipstmserver</span>. It consists of two separate programs: the test client and the test server. The server handles requests containing a single word "Hello" by sending a response greeting back to the client. This example would work for named pipes as well, i.e. if you replace the class names <span class="lang">ipstream</span> and <span class="lang">ipstmserver</span> with <span class="lang">namedpipe</span> and <span class="lang">npserver</span> and fix the construction parameters.</p><p><u>Client:</u></p><blockquote> <pre>#include <pinet.h>USING_PTYPESconst int testport = 8085;const int maxtoken = 4096;int main(){ <span class="comment">// create a client socket and send a greeting to the server // assuming that the server is on the same host (127.0.0.1)</span> ipstream client(ipaddress(127, 0, 0, 1), testport); try { client.open(); pout.put("Sending a request to the server...\n"); client.putline("Hello"); client.flush(); <span class="comment">// receive the response</span> string rsp = client.line(maxtoken); pout.putf("Received: %s\n", pconst(rsp)); <span class="comment">// need to close the socket explicitly to gracefully shutdown // the peer host too. otherwise, ~ipstream() will call cancel() // and leave the peer in a waiting state (not forever though)</span>. client.close(); } catch(estream* e) { perr.putf("Error: %s\n", pconst(e->get_message())); delete e; } return 0;}</pre></blockquote><p> </p><p><u>Server:</u></p><blockquote> <pre>#include <ptime.h>#include <pinet.h>USING_PTYPESconst int testport = 8085;const int maxtoken = 4096;void servermain(ipstmserver& svr){ ipstream client; pout.putf("Ready to answer queries on port %d\n", testport); while(true) { <span class="comment">// serve() will wait for a connection request and will prepare // the supplied ipstream object for talking to the peer. // note that (unlikely) exceptions thrown in serve() will be // caught in main()</span> svr.serve(client); <span class="comment">// for better performance the server would start a new thread // for each client request. for simplicity, we serve the request // in-place:</span> if (client.get_active()) { try { <span class="comment">// read the request line: // real-world network applications should limit input data // to prevent potential denial-of-service attacks</span> string req = lowercase(client.line(maxtoken)); if (req == "hello") { <span class="comment">// try to reverse-lookup the client's IP</span> string host = phostbyaddr(client.get_ip()); if (isempty(host)) host = iptostring(client.get_ip()); <span class="comment">// now send our greeting to the client</span> client.putline("Hello, " + host + " (" + iptostring(client.get_ip()) + "), nice to see you!"); client.flush(); <span class="comment">// log this request</span> string timestamp = nowstring("%d-%b-%Y %H:%M:%S", false); pout.putf("%s greeting received from %s (%s)\n", pconst(timestamp), pconst(host), pconst(iptostring(client.get_ip()))); } client.close(); } catch(estream* e) { perr.putf("Error: %s\n", pconst(e->get_message())); delete e; } } }}int main(){ ipstmserver svr; try { <span class="comment">// bind to all local addresses on port 8085</span> svr.bindall(testport);<span class="comment"> // enter an infinite loop of serving requests</span> servermain(svr); } catch(estream* e) { perr.putf("FATAL: %s\n", pconst(e->get_message())); delete e; } return 0;}</pre></blockquote><p> </p><p><b>Example 2</b>. This example demonstrates the use of message-oriented networking interfaces <span class="lang">ipmessage</span> and <span class="lang">ipmsgserver</span>. The client sends a broadcast message to the local network and waits for a response. It may retry the request several times.</p><p><u>Client:</u></p><blockquote><pre>#include <pinet.h>USING_PTYPESconst int testport = 8085;const int maxtoken = 4096;const int tries = 3;const int firsttimeout = 2000;bool dorequest(int timeout){ ipmessage msg(ipbcast, testport); try { pout.put("Broadcasting a request...\n"); msg.send("Hello"); <span class="comment">// wait for a response the specified amount of time</span> if (!msg.waitfor(timeout)) return false; string rsp = msg.receive(maxtoken); pout.putf("Received: %s\n", pconst(rsp)); } catch(estream* e) { perr.putf("Error: %s\n", pconst(e->get_message())); delete e; } return true;}int main(){ int timeout = firsttimeout; for (int i = 0; i < tries; i++) { if (dorequest(timeout)) break; <span class="comment">// double the timeout value</span> timeout *= 2; } return 0;}</pre></blockquote><p> </p><p><u>Server:</u></p><blockquote><pre>#include <ptime.h>#include <pinet.h>USING_PTYPESconst int testport = 8085;const int maxtoken = 4096;void servermain(ipmsgserver& svr){ pout.putf("Ready to answer queries on port %d\n", testport); bool quit = false; do { try { <span class="comment">// receive the "hello" request and send a simple answer // back to the client</span> string req = lowercase(svr.receive(maxtoken)); if (req == "hello") { string host = svr.get_host(); if (isempty(host)) host = iptostring(svr.get_ip()); svr.send("Hello, " + host + " (" + iptostring(svr.get_ip()) + "), nice to see you!"); <span class="comment">// log this request</span> string timestamp = nowstring("%d-%b-%Y %H:%M:%S", false); pout.putf("%s greeting received from %s (%s)\n", pconst(timestamp), pconst(host), pconst(iptostring(svr.get_ip()))); } } catch(estream* e) { perr.putf("Server error: %s\n", pconst(e->get_message())); delete e; } } while (!quit);}int main(){ ipmsgserver svr; try { svr.bindall(testport); <span class="comment">// try to listen on socket once to generate an error right away, // before entering the main server loop</span> svr.poll(); <span class="comment">// enter an infinite loop of serving requests</span> servermain(svr); } catch(estream* e) { perr.putf("FATAL: %s\n", pconst(e->get_message())); delete e; } return 0;}</pre></blockquote><p class="seealso">See also: <a href="inet.ipstream.html">ipstream</a>, <a href="inet.ipstmserver.html">ipstmserver</a>, <a href="inet.ipmessage.html">ipmessage</a>, <a href="inet.ipmsgserver.html">ipmsgserver</a>, <a href="inet.utils.html">Utilities</a></p><!-- #EndEditable --><hr size="1"><a href="../index.html" class="ns">PTypes home</a></body><!-- #EndTemplate --></html>⌨️ 快捷键说明
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