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89 lines
3.5 KiB
C++
Executable File
89 lines
3.5 KiB
C++
Executable File
// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
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/*
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This is an example illustrating the use of the sockets and
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sockstreambuf components from the dlib C++ Library.
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This program simply connects to www.google.com at port 80 and requests the
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main Google web page. It then prints what it gets back from Google to the
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screen.
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For those of you curious about HTTP check out the excellent introduction at
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http://www.jmarshall.com/easy/http/
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*/
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#include "dlib/sockets.h"
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#include "dlib/sockstreambuf.h"
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#include <iostream>
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using namespace std;
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using namespace dlib;
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int main()
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{
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try
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{
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// Connect to Google's web server which listens on port 80. If this
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// fails it will throw a dlib::socket_error exception. Note that we
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// are using a smart pointer here to contain the connection pointer
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// returned from connect. Doing this ensures that the connection
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// is deleted even if someone throws an exception somewhere in your code.
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scoped_ptr<connection> con(connect("www.google.com",80));
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{
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// Create a stream buffer for our connection
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sockstreambuf::kernel_2a buf(con);
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// Now stick that stream buffer into an iostream object
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iostream stream(&buf);
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// This command causes the iostream to flush its output buffers
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// whenever someone makes a read request.
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stream.tie(&stream);
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// Now we make the HTTP GET request for the main Google page.
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stream << "GET / HTTP/1.0\r\n\r\n";
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// Here we print each character we get back one at a time.
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int ch = stream.get();
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while (ch != EOF)
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{
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cout << (char)ch;
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ch = stream.get();
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}
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// At the end of this scope buf will be destructed and flush
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// anything it still contains to the connection. Thus putting
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// this } here makes it safe to destroy the connection later on.
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// If we just destroyed the connection before buf was destructed
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// then buf might try to flush its data to a closed connection
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// which would be an error.
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}
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// Here we call close_gracefully(). It takes a connection and performs
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// a proper TCP shutdown by sending a FIN packet to the other end of the
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// connection and waiting half a second for the other end to close the
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// connection as well. If half a second goes by without the other end
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// responding then the connection is forcefully shutdown and deleted.
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//
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// You usually want to perform a graceful shutdown of your TCP connections
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// because there might be some data you tried to send that is still buffered
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// in the operating system's output buffers. If you just killed the
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// connection it might not be sent to the other side (although maybe
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// you don't care, and in the case of this example it doesn't really matter.
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// But I'm only putting this here for the purpose of illustration :-).
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// In any case, this function is provided to allow you to perform a graceful
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// close if you so choose.
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//
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// Also note that the timeout can be changed by suppling an optional second
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// argument to this function.
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close_gracefully(con);
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}
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catch (exception& e)
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{
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cout << e.what() << endl;
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}
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}
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