230 lines
10 KiB
HTML
230 lines
10 KiB
HTML
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<!DOCTYPE html
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<meta name="DC.Title" content="Example: Write an iterative server program" />
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<meta name="abstract" content="Use this example to create a single server job that handles all incoming connections. When the accept() API is completed, the server handles the entire transaction." />
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<meta name="description" content="Use this example to create a single server job that handles all incoming connections. When the accept() API is completed, the server handles the entire transaction." />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Example: Write an iterative server program</title>
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</head>
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<body id="xiterative"><a name="xiterative"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Example: Write an iterative server program</h1>
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<div><p>Use this example to create a single server job that handles all
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incoming connections. When the <span class="apiname">accept()</span> API is completed,
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the server handles the entire transaction.</p>
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<div class="section"><p>The figure illustrates how the server and client jobs interact
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when the system used the iterative server design. </p>
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</div>
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<div class="section"><p><br /><img src="rxab6505.gif" alt="Server and client job interaction when using iterative server design." /><br /></p>
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</div>
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<div class="section"></div>
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<div class="section"><h4 class="sectiontitle">Flow of socket events: Iterative server</h4><p>The
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following sequence of the socket calls provide a description of the graphic.
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It also describes the relationship between the server and worker applications.
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Each set of flows contain links to usage notes on specific APIs. If you need
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more details on the use of a particular API, you can use these links. The
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following sequence shows the function calls for the iterative server application:</p>
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<ol><li>The <span class="apiname">socket()</span> function returns a socket descriptor representing
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an endpoint. The statement also identifies that the INET (Internet Protocol)
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address family with the TCP transport (SOCK_STREAM) is used for this socket. </li>
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<li>After the socket descriptor is created, the <span class="apiname">bind()</span> function
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gets a unique name for the socket. </li>
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<li>The <span class="apiname">listen()</span> allows the server to accept incoming client
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connections. </li>
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<li>The server uses the <span class="apiname">accept()</span> function to accept an
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incoming connection request. The <span class="apiname">accept()</span> call blocks indefinitely
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waiting for the incoming connection to arrive.</li>
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<li>The <span class="apiname">recv()</span> function receives data from the client application. </li>
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<li>The <span class="apiname">send() </span> function echoes the data back to the client. </li>
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<li>The <span class="apiname">close()</span> function closes any open socket descriptors.</li>
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</ol>
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</div>
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<div class="section"><div class="note"><span class="notetitle">Note:</span> By using the code examples, you agree to the terms of the <a href="codedisclaimer.htm">Code license and disclaimer information</a>.</div>
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<pre>/**************************************************************************/
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/* Application creates an iterative server design */
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/**************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#define SERVER_PORT 12345
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main (int argc, char *argv[])
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{
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int i, len, num, rc, on = 1;
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int listen_sd, accept_sd;
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char buffer[80];
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struct sockaddr_in addr;
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/*************************************************/
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/* If an argument was specified, use it to */
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/* control the number of incoming connections */
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/*************************************************/
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if (argc >= 2)
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num = atoi(argv[1]);
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else
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num = 1;
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/*************************************************/
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/* Create an AF_INET stream socket to receive */
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/* incoming connections on */
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/*************************************************/
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listen_sd = socket(AF_INET, SOCK_STREAM, 0);
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if (listen_sd < 0)
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{
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perror("socket() failed");
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exit(-1);
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}
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/*************************************************/
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/* Allow socket descriptor to be reuseable */
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/*************************************************/
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rc = setsockopt(listen_sd,
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SOL_SOCKET, SO_REUSEADDR,
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(char *)&on, sizeof(on));
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if (rc < 0)
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{
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perror("setsockopt() failed");
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close(listen_sd);
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exit(-1);
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}
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/*************************************************/
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/* Bind the socket */
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/*************************************************/
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memset(&addr, 0, sizeof(addr));
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addr.sin_family = AF_INET;
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addr.sin_addr.s_addr = htonl(INADDR_ANY);
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addr.sin_port = htons(SERVER_PORT);
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rc = bind(listen_sd,
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(struct sockaddr *)&addr, sizeof(addr));
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if (rc < 0)
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{
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perror("bind() failed");
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close(listen_sd);
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exit(-1);
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}
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/*************************************************/
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/* Set the listen back log */
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/*************************************************/
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rc = listen(listen_sd, 5);
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if (rc < 0)
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{
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perror("listen() failed");
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close(listen_sd);
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exit(-1);
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}
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/*************************************************/
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/* Inform the user that the server is ready */
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/*************************************************/
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printf("The server is ready\n");
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/*************************************************/
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/* Go through the loop once for each connection */
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/*************************************************/
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for (i=0; i < num; i++)
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{
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/**********************************************/
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/* Wait for an incoming connection */
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/**********************************************/
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printf("Interation: %d\n", i+1);
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printf(" waiting on accept()\n");
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accept_sd = accept(listen_sd, NULL, NULL);
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if (accept_sd < 0)
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{
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perror("accept() failed");
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close(listen_sd);
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exit(-1);
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}
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printf(" accept completed successfully\n");
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/**********************************************/
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/* Receive a message from the client */
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/**********************************************/
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printf(" wait for client to send us a message\n");
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rc = recv(accept_sd, buffer, sizeof(buffer), 0);
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if (rc <= 0)
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{
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perror("recv() failed");
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close(listen_sd);
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close(accept_sd);
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exit(-1);
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}
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printf(" <%s>\n", buffer);
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/**********************************************/
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/* Echo the data back to the client */
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/**********************************************/
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printf(" echo it back\n");
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len = rc;
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rc = send(accept_sd, buffer, len, 0);
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if (rc <= 0)
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{
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perror("send() failed");
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close(listen_sd);
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close(accept_sd);
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exit(-1);
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}
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/**********************************************/
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/* Close down the incoming connection */
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/**********************************************/
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close(accept_sd);
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}
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/*************************************************/
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/* Close down the listen socket */
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/*************************************************/
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close(listen_sd);
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}</pre>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="xcodesigns.htm" title="There are a number of ways that you can design a connection-oriented socket server on the iSeries. These example programs can be used to create your own connection-oriented designs.">Examples: Connection-oriented designs</a></div>
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</div>
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<div class="relref"><strong>Related reference</strong><br />
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<div><a href="generic.htm" title="This code example contains the code for a common client job.">Example: Generic client</a></div>
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</div>
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<div class="relinfo"><strong>Related information</strong><br />
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<div><a href="../apis/recv.htm">recv()</a></div>
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<div><a href="../apis/bind.htm">bind()</a></div>
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<div><a href="../apis/socket.htm">socket()</a></div>
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<div><a href="../apis/listen.htm">listen()</a></div>
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<div><a href="../apis/accept.htm">accept()</a></div>
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<div><a href="../apis/send.htm">send()</a></div>
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<div><a href="../apis/close.htm">close()</a></div>
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</div>
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</div>
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</body>
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</html> |