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<html><!-- #BeginTemplate "/Templates/tmpl.dwt" --><!-- DW6 -->
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<title>PTypes: networking: examples</title>
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<p><a href="../index.html"><img src="title-21.png" width="253" height="39" alt="C++ Portable Types Library (PTypes) Version 2.1" border="0"></a> 
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<p class="hpath"><a href="index.html">Top</a>: <a href="inet.html">Networking</a>: 
Examples</p>
<p><b><br>
Example 1</b>. A simple IP client that tries to retrieve the main page at www.yahoo.com  via an HTTP request. </p>
<blockquote> 
<pre>
#include <pinet.h>
 
USING_PTYPES
 
int main()
{
    ipstream client("www.yahoo.com", 80);
 
    try
    {
        client.open();
 
        <span class="comment">// send a valid HTTP/1.1 request</span>
        client.put("GET / HTTP/1.1\r\n"<br>            "Accept: * /*\r\n"<br>            "User-Agent: TestAgent/1.0\r\n"<br>            "Host: www.yahoo.com\r\n"<br>            "Connection: close\r\n\r\n");
        client.flush();
 
        <span class="comment">// receive the response and print it line by line</span>
        while (!client.get_eof())
            pout.putline(client.line());
 
        client.close();
    }
    catch(estream* e)
    {
        perr.putf("Error: %s\n", pconst(e->get_message()));
        delete e;
    }
 
    return 0;
}</pre>
</blockquote>
<p><b>Example 2 </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 programs:  test client and test server. The 
server handles requests that contain 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_PTYPES
 
const 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_PTYPES
 
const 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. see multithreading examples for the full multithreaded
        // server template.</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>
                    pout.putf("%t  greeting received from %s (%a)\n",
                        now(), pconst(host), long(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><b>Example 3 </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_PTYPES
 
const 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;
         
        ipaddress src;
        string rsp = msg.receive(maxtoken, src);
        pout.putf("Received: '%s' (from %a)\n", pconst(rsp), long(src));
    }
    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_PTYPES
 
const 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>
                pout.putf("%t  greeting received from %s (%a)\n",
                    now(), pconst(host), long(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>, <a href="async.examples.html">Multithreading 
examples</a></p>
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Source at commit 8edbcdac0d39 created 11 years 11 months ago. By Nathan Adams, initial commit
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