Clients/BonjourExample/BonjourExample.cpp

   1 /*
   2  * Copyright (c) 2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22
  23     Change History (most recent first):
  24
  25 $Log: BonjourExample.cpp,v $
  26 Revision 1.1  2005/05/20 22:01:01  bradley
  27 Bonjour for Windows example code to browse for HTTP services and deliver via Window messages.
  28
  29 */
  30
  31 #include        "stdafx.h"
  32
  33 #include        <assert.h>
  34 #include        <stdio.h>
  35
  36 #include        "dns_sd.h"
  37
  38 // Constants
  39
  40 #define BONJOUR_EVENT           ( WM_USER + 0x100 )     // Message sent to the Window when a Bonjour event occurs.
  41
  42 // Prototypes
  43
  44 static LRESULT CALLBACK WndProc( HWND inWindow, UINT inMsg, WPARAM inWParam, LPARAM inLParam );
  45
  46 static void DNSSD_API
  47         BrowserCallBack(
  48                 DNSServiceRef           inServiceRef,
  49                 DNSServiceFlags         inFlags,
  50                 uint32_t                        inIFI,
  51                 DNSServiceErrorType     inError,
  52                 const char *            inName,
  53                 const char *            inType,
  54                 const char *            inDomain,
  55                 void *                          inContext );
  56
  57 // Globals
  58
  59 DNSServiceRef           gServiceRef = NULL;
  60
  61 // Main entry point for application.
  62
  63 int _tmain( int argc, _TCHAR *argv[] )
  64 {
  65         HINSTANCE                               instance;
  66         WNDCLASSEX                              wcex;
  67         HWND                                    wind;
  68         MSG                                             msg;
  69         DNSServiceErrorType             err;
  70
  71         (void) argc; // Unused
  72         (void) argv; // Unused
  73
  74         // Create the window. This window won't actually be shown, but it demonstrates how to use Bonjour
  75         // with Windows GUI applications by having Bonjour events processed as messages to a Window.
  76
  77         instance = GetModuleHandle( NULL );
  78         assert( instance );
  79
  80         wcex.cbSize                     = sizeof( wcex );
  81         wcex.style                      = 0;
  82         wcex.lpfnWndProc        = (WNDPROC) WndProc;
  83         wcex.cbClsExtra         = 0;
  84         wcex.cbWndExtra         = 0;
  85         wcex.hInstance          = instance;
  86         wcex.hIcon                      = NULL;
  87         wcex.hCursor            = NULL;
  88         wcex.hbrBackground      = NULL;
  89         wcex.lpszMenuName       = NULL;
  90         wcex.lpszClassName      = TEXT( "BonjourExample" );
  91         wcex.hIconSm            = NULL;
  92         RegisterClassEx( &wcex );
  93
  94         wind = CreateWindow( wcex.lpszClassName, wcex.lpszClassName, 0, CW_USEDEFAULT, 0, CW_USEDEFAULT,
  95                 0, NULL, NULL, instance, NULL );
  96         assert( wind );
  97
  98         // Start browsing for services and associate the Bonjour browser with our window using the
  99         // WSAAsyncSelect mechanism. Whenever something related to the Bonjour browser occurs, our
 100         // private Windows message will be sent to our window so we can give Bonjour a chance to
 101         // process it. This allows Bonjour to avoid using a secondary thread (and all the issues
 102         // with synchronization that would introduce), but still process everything asynchronously.
 103         // This also simplifies app code because Bonjour will only run when we explicitly call it.
 104
 105         err = DNSServiceBrowse(
 106                 &gServiceRef,                                   // Receives reference to Bonjour browser object.
 107                 0,                                                              // No flags.
 108                 kDNSServiceInterfaceIndexAny,   // Browse on all network interfaces.
 109                 "_http._tcp",                                   // Browse for HTTP service types.
 110                 NULL,                                                   // Browse on the default domain (e.g. local.).
 111                 BrowserCallBack,                                // Callback function when Bonjour events occur.
 112                 NULL );                                                 // No callback context needed.
 113         assert( err == kDNSServiceErr_NoError );
 114
 115         err = WSAAsyncSelect( (SOCKET) DNSServiceRefSockFD( gServiceRef ), wind, BONJOUR_EVENT, FD_READ | FD_CLOSE );
 116         assert( err == kDNSServiceErr_NoError );
 117
 118         fprintf( stderr, "Browsing for _http._tcp\n" );
 119
 120         // Main event loop for the application. All Bonjour events are dispatched while in this loop.
 121
 122         while( GetMessage( &msg, NULL, 0, 0 ) )
 123         {
 124                 TranslateMessage( &msg );
 125                 DispatchMessage( &msg );
 126         }
 127
 128         // Clean up Bonjour. This is not strictly necessary since the normal process cleanup will
 129         // close Bonjour socket(s) and release memory, but it's here to demonstrate how to do it.
 130
 131         if( gServiceRef )
 132         {
 133                 WSAAsyncSelect( (SOCKET) DNSServiceRefSockFD( gServiceRef ), wind, BONJOUR_EVENT, 0 );
 134                 DNSServiceRefDeallocate( gServiceRef );
 135         }
 136         return( 0 );
 137 }
 138
 139 // Callback for the Window. Bonjour events are delivered here.
 140
 141 static LRESULT CALLBACK WndProc( HWND inWindow, UINT inMsg, WPARAM inWParam, LPARAM inLParam )
 142 {
 143         LRESULT                                 result;
 144         DNSServiceErrorType             err;
 145
 146         switch( inMsg )
 147         {
 148                 case BONJOUR_EVENT:
 149
 150                         // Process the Bonjour event. All Bonjour callbacks occur from within this function.
 151                         // If an error occurs while trying to process the result, it most likely means that
 152                         // something serious has gone wrong with Bonjour, such as it being terminated. This
 153                         // does not normally occur, but code should be prepared to handle it. If the error
 154                         // is ignored, the window will receive a constant stream of BONJOUR_EVENT messages so
 155                         // if an error occurs, we disassociate the DNSServiceRef from the window, deallocate
 156                         // it, and invalidate the reference so we don't try to deallocate it again on quit.
 157                         // Since this is a simple example app, if this error occurs, we quit the app too.
 158
 159                         err = DNSServiceProcessResult( gServiceRef );
 160                         if( err != kDNSServiceErr_NoError )
 161                         {
 162                                 fprintf( stderr, "### ERROR! serious Bonjour error: %d\n", err );
 163
 164                                 WSAAsyncSelect( (SOCKET) DNSServiceRefSockFD( gServiceRef ), inWindow, BONJOUR_EVENT, 0 );
 165                                 DNSServiceRefDeallocate( gServiceRef );
 166                                 gServiceRef = NULL;
 167
 168                                 PostQuitMessage( 0 );
 169                         }
 170                         result = 0;
 171                         break;
 172
 173                 default:
 174                         result = DefWindowProc( inWindow, inMsg, inWParam, inLParam );
 175                         break;
 176         }
 177         return( result );
 178 }
 179
 180 // Callback for Bonjour browser events. Called when services are added or removed.
 181
 182 static void DNSSD_API
 183         BrowserCallBack(
 184                 DNSServiceRef           inServiceRef,
 185                 DNSServiceFlags         inFlags,
 186                 uint32_t                        inIFI,
 187                 DNSServiceErrorType     inError,
 188                 const char *            inName,
 189                 const char *            inType,
 190                 const char *            inDomain,
 191                 void *                          inContext )
 192 {
 193         (void) inServiceRef;    // Unused
 194         (void) inContext;               // Unused
 195
 196         if( inError == kDNSServiceErr_NoError )
 197         {
 198                 const char *            action;
 199                 const char *            more;
 200
 201                 if( inFlags & kDNSServiceFlagsAdd )                     action  = "ADD";
 202                 else                                                                            action  = "RMV";
 203                 if( inFlags & kDNSServiceFlagsMoreComing )      more    = " (MORE)";
 204                 else                                                                            more    = "";
 205
 206                 fprintf( stderr, "%s %30s.%s%s on interface %d%s\n", action, inName, inType, inDomain, (int) inIFI, more );
 207         }
 208         else
 209         {
 210                 fprintf( stderr, "Bonjour browser error occurred: %d\n", inError );
 211         }
 212 }