Clients/BonjourExample/BonjourExample.cpp

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  *
   3  * Copyright (c) 2005 Apple Computer, Inc. All rights reserved.
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16
  17     Change History (most recent first):
  18
  19 $Log: BonjourExample.cpp,v $
  20 Revision 1.2  2006/08/14 23:23:57  cheshire
  21 Re-licensed mDNSResponder daemon source code under Apache License, Version 2.0
  22
  23 Revision 1.1  2005/05/20 22:01:01  bradley
  24 Bonjour for Windows example code to browse for HTTP services and deliver via Window messages.
  25
  26 */
  27
  28 #include        "stdafx.h"
  29
  30 #include        <assert.h>
  31 #include        <stdio.h>
  32
  33 #include        "dns_sd.h"
  34
  35 // Constants
  36
  37 #define BONJOUR_EVENT           ( WM_USER + 0x100 )     // Message sent to the Window when a Bonjour event occurs.
  38
  39 // Prototypes
  40
  41 static LRESULT CALLBACK WndProc( HWND inWindow, UINT inMsg, WPARAM inWParam, LPARAM inLParam );
  42
  43 static void DNSSD_API
  44         BrowserCallBack(
  45                 DNSServiceRef           inServiceRef,
  46                 DNSServiceFlags         inFlags,
  47                 uint32_t                        inIFI,
  48                 DNSServiceErrorType     inError,
  49                 const char *            inName,
  50                 const char *            inType,
  51                 const char *            inDomain,
  52                 void *                          inContext );
  53
  54 // Globals
  55
  56 DNSServiceRef           gServiceRef = NULL;
  57
  58 // Main entry point for application.
  59
  60 int _tmain( int argc, _TCHAR *argv[] )
  61 {
  62         HINSTANCE                               instance;
  63         WNDCLASSEX                              wcex;
  64         HWND                                    wind;
  65         MSG                                             msg;
  66         DNSServiceErrorType             err;
  67
  68         (void) argc; // Unused
  69         (void) argv; // Unused
  70
  71         // Create the window. This window won't actually be shown, but it demonstrates how to use Bonjour
  72         // with Windows GUI applications by having Bonjour events processed as messages to a Window.
  73
  74         instance = GetModuleHandle( NULL );
  75         assert( instance );
  76
  77         wcex.cbSize                     = sizeof( wcex );
  78         wcex.style                      = 0;
  79         wcex.lpfnWndProc        = (WNDPROC) WndProc;
  80         wcex.cbClsExtra         = 0;
  81         wcex.cbWndExtra         = 0;
  82         wcex.hInstance          = instance;
  83         wcex.hIcon                      = NULL;
  84         wcex.hCursor            = NULL;
  85         wcex.hbrBackground      = NULL;
  86         wcex.lpszMenuName       = NULL;
  87         wcex.lpszClassName      = TEXT( "BonjourExample" );
  88         wcex.hIconSm            = NULL;
  89         RegisterClassEx( &wcex );
  90
  91         wind = CreateWindow( wcex.lpszClassName, wcex.lpszClassName, 0, CW_USEDEFAULT, 0, CW_USEDEFAULT,
  92                 0, NULL, NULL, instance, NULL );
  93         assert( wind );
  94
  95         // Start browsing for services and associate the Bonjour browser with our window using the
  96         // WSAAsyncSelect mechanism. Whenever something related to the Bonjour browser occurs, our
  97         // private Windows message will be sent to our window so we can give Bonjour a chance to
  98         // process it. This allows Bonjour to avoid using a secondary thread (and all the issues
  99         // with synchronization that would introduce), but still process everything asynchronously.
 100         // This also simplifies app code because Bonjour will only run when we explicitly call it.
 101
 102         err = DNSServiceBrowse(
 103                 &gServiceRef,                                   // Receives reference to Bonjour browser object.
 104                 0,                                                              // No flags.
 105                 kDNSServiceInterfaceIndexAny,   // Browse on all network interfaces.
 106                 "_http._tcp",                                   // Browse for HTTP service types.
 107                 NULL,                                                   // Browse on the default domain (e.g. local.).
 108                 BrowserCallBack,                                // Callback function when Bonjour events occur.
 109                 NULL );                                                 // No callback context needed.
 110         assert( err == kDNSServiceErr_NoError );
 111
 112         err = WSAAsyncSelect( (SOCKET) DNSServiceRefSockFD( gServiceRef ), wind, BONJOUR_EVENT, FD_READ | FD_CLOSE );
 113         assert( err == kDNSServiceErr_NoError );
 114
 115         fprintf( stderr, "Browsing for _http._tcp\n" );
 116
 117         // Main event loop for the application. All Bonjour events are dispatched while in this loop.
 118
 119         while( GetMessage( &msg, NULL, 0, 0 ) )
 120         {
 121                 TranslateMessage( &msg );
 122                 DispatchMessage( &msg );
 123         }
 124
 125         // Clean up Bonjour. This is not strictly necessary since the normal process cleanup will
 126         // close Bonjour socket(s) and release memory, but it's here to demonstrate how to do it.
 127
 128         if( gServiceRef )
 129         {
 130                 WSAAsyncSelect( (SOCKET) DNSServiceRefSockFD( gServiceRef ), wind, BONJOUR_EVENT, 0 );
 131                 DNSServiceRefDeallocate( gServiceRef );
 132         }
 133         return( 0 );
 134 }
 135
 136 // Callback for the Window. Bonjour events are delivered here.
 137
 138 static LRESULT CALLBACK WndProc( HWND inWindow, UINT inMsg, WPARAM inWParam, LPARAM inLParam )
 139 {
 140         LRESULT                                 result;
 141         DNSServiceErrorType             err;
 142
 143         switch( inMsg )
 144         {
 145                 case BONJOUR_EVENT:
 146
 147                         // Process the Bonjour event. All Bonjour callbacks occur from within this function.
 148                         // If an error occurs while trying to process the result, it most likely means that
 149                         // something serious has gone wrong with Bonjour, such as it being terminated. This
 150                         // does not normally occur, but code should be prepared to handle it. If the error
 151                         // is ignored, the window will receive a constant stream of BONJOUR_EVENT messages so
 152                         // if an error occurs, we disassociate the DNSServiceRef from the window, deallocate
 153                         // it, and invalidate the reference so we don't try to deallocate it again on quit.
 154                         // Since this is a simple example app, if this error occurs, we quit the app too.
 155
 156                         err = DNSServiceProcessResult( gServiceRef );
 157                         if( err != kDNSServiceErr_NoError )
 158                         {
 159                                 fprintf( stderr, "### ERROR! serious Bonjour error: %d\n", err );
 160
 161                                 WSAAsyncSelect( (SOCKET) DNSServiceRefSockFD( gServiceRef ), inWindow, BONJOUR_EVENT, 0 );
 162                                 DNSServiceRefDeallocate( gServiceRef );
 163                                 gServiceRef = NULL;
 164
 165                                 PostQuitMessage( 0 );
 166                         }
 167                         result = 0;
 168                         break;
 169
 170                 default:
 171                         result = DefWindowProc( inWindow, inMsg, inWParam, inLParam );
 172                         break;
 173         }
 174         return( result );
 175 }
 176
 177 // Callback for Bonjour browser events. Called when services are added or removed.
 178
 179 static void DNSSD_API
 180         BrowserCallBack(
 181                 DNSServiceRef           inServiceRef,
 182                 DNSServiceFlags         inFlags,
 183                 uint32_t                        inIFI,
 184                 DNSServiceErrorType     inError,
 185                 const char *            inName,
 186                 const char *            inType,
 187                 const char *            inDomain,
 188                 void *                          inContext )
 189 {
 190         (void) inServiceRef;    // Unused
 191         (void) inContext;               // Unused
 192
 193         if( inError == kDNSServiceErr_NoError )
 194         {
 195                 const char *            action;
 196                 const char *            more;
 197
 198                 if( inFlags & kDNSServiceFlagsAdd )                     action  = "ADD";
 199                 else                                                                            action  = "RMV";
 200                 if( inFlags & kDNSServiceFlagsMoreComing )      more    = " (MORE)";
 201                 else                                                                            more    = "";
 202
 203                 fprintf( stderr, "%s %30s.%s%s on interface %d%s\n", action, inName, inType, inDomain, (int) inIFI, more );
 204         }
 205         else
 206         {
 207                 fprintf( stderr, "Bonjour browser error occurred: %d\n", inError );
 208         }
 209 }