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