_Help File Web Links_
by Robert Lord

Listing One

1   // URLHelp.c -- written by Bob Lord 3/96
2   
3   #include <windows.h>
4   #include <ddeml.h>
5   #include <limits.h>
6   #include <stdio.h>
7   
8   extern HWND FindWindowByTitle(LPCSTR lpszTitle);
9   
10  const char cszDDECommandKey[]     = 
11    "SOFTWARE\\classes\\http\\shell\\open\\command";
12  const char cszDDEExecKey[]        = 
13    "SOFTWARE\\classes\\http\\shell\\open\\ddeexec";
14  const char cszDDEApplicationKey[] = 
15    "SOFTWARE\\classes\\http\\shell\\open\\ddeexec\\Application";
16  const char cszDDETopicKey[]       = 
17    "SOFTWARE\\classes\\http\\shell\\open\\ddeexec\\Topic";
18  
19  HDDEDATA CALLBACK DdeCallback(UINT uType, UINT uFmt, HCONV hconv, HSZ hsz1,
20                                HSZ hsz2, HDDEDATA hdata, DWORD dwData1,
21                                DWORD dwData2) 
22  { 
23      switch (uType)
24      { 
25          case XTYP_ADVDATA: 
26              return (HDDEDATA)DDE_FACK; 
27  
28          default: 
29              return (HDDEDATA)NULL; 
30      } 
31  } 
32   
33  LONG GetRegSzValue(HKEY hKey, LPCTSTR lpSubKey, LPCTSTR lpName,
34                     LPSTR *lplpszValue)
35  {
36      LONG result;
37      HKEY hkRegKey;
38      DWORD dwType;
39      DWORD dwSize;
40      
41      result = RegOpenKeyEx(hKey, lpSubKey, 0L, KEY_READ, &hkRegKey);
42      if (result == ERROR_SUCCESS)
43      {
44          result = RegQueryValueEx(hkRegKey, lpName, NULL, &dwType, NULL,
45                                   &dwSize);
46          if (result == ERROR_SUCCESS)
47          {
48              *lplpszValue = NULL;
49              if (dwType == REG_SZ)
50                  if (dwSize != 0 && dwSize <= UINT_MAX)
51                  {   
52                      *lplpszValue = malloc(dwSize);
53                      if (*lplpszValue != NULL)
54                          result = RegQueryValueEx(hkRegKey, lpName, NULL,
55                                                 &dwType,*lplpszValue,&dwSize);
56                  }
57          }
58          RegCloseKey(hkRegKey);
59          if (*lplpszValue == NULL)
60               result = ERROR_INVALID_FUNCTION;
61      }
62      return result;
63  }
64  
65  __declspec(dllexport) void DisplayURL(LPCSTR lpszURL)
66  {
67      LPSTR lpszCommand=NULL;
68      LPSTR lpszExec=NULL;
69      LPSTR lpszURLExec=NULL;
70      LPSTR lpszApplication=NULL;
71      LPSTR lpszTopic=NULL;
72      DWORD idInst=0;
73      HSZ hszService, hszTopic, hszItem;
74      HCONV hConv;
75      HDDEDATA hData;
76      HCURSOR hcurStarting, hcurOld;
77      
78      hcurStarting = LoadCursor(NULL, IDC_APPSTARTING);
79      hcurOld = SetCursor(hcurStarting);
80  
81      GetRegSzValue(HKEY_LOCAL_MACHINE, cszDDEExecKey, NULL, &lpszExec);
82      if (lpszExec)
83      {
84          lpszURLExec = malloc(lstrlen(lpszExec) - 2 + lstrlen(lpszURL) + 1);
85          if (lpszURLExec)
86          {
87              char *pFrom = lpszExec;
88              char *pTo = lpszURLExec;
89  
90              while (*pFrom != '%' && *(pFrom + 1) != '1')
91                  *pTo++ = *pFrom++;
92              lstrcpy(pTo, lpszURL);
93              pFrom += 2;
94              lstrcat(pTo, pFrom);
95          }
96      }
97      free(lpszExec);
98  
99      GetRegSzValue(HKEY_LOCAL_MACHINE, cszDDECommandKey, NULL, &lpszCommand);
100     GetRegSzValue(HKEY_LOCAL_MACHINE, cszDDEApplicationKey, NULL,
101                   &lpszApplication);
102     GetRegSzValue(HKEY_LOCAL_MACHINE, cszDDETopicKey, NULL, &lpszTopic);
103 
104     if (lpszCommand && lpszURLExec && lpszApplication && lpszTopic)
105     {
106         if (DdeInitialize(&idInst, DdeCallback,
107           APPCLASS_STANDARD | APPCMD_CLIENTONLY, 0L) == DMLERR_NO_ERROR)
108         {
109             hszService = DdeCreateStringHandle(idInst, lpszApplication,
110                                                CP_WINANSI);
111             hszTopic = DdeCreateStringHandle(idInst, lpszTopic, CP_WINANSI);
112             if (hszService && hszTopic)
113             {
114                 hConv = DdeConnect(idInst, hszService, hszTopic, NULL);
115                 if (!hConv)
116                     WinExec(lpszCommand, SW_SHOWNORMAL);
117                 hConv = DdeConnect(idInst, hszService, hszTopic, NULL);
118                 if (hConv)
119                 {
120                     DdeClientTransaction((LPSTR)lpszURLExec,
121                       lstrlen(lpszURLExec) + 1, hConv, 0, 0, XTYP_EXECUTE,
122                       TIMEOUT_ASYNC, NULL);
123                     DdeDisconnect(hConv);
124                 }
125             }
126 
127             if (lstrcmp(lpszApplication, "IExplore") != 0)
128             {
129                 if (hszTopic)
130                     DdeFreeStringHandle(idInst, hszTopic);
131                 hszTopic = DdeCreateStringHandle(idInst, "WWW_GetWindowInfo",
132                                                  CP_WINANSI);
133                 hszItem = DdeCreateStringHandle(idInst, "-1", CP_WINANSI);
134                 if (hszService && hszTopic && hszItem)
135                 {
136                     hConv = DdeConnect(idInst, hszService, hszTopic, NULL);
137                     if (hConv)
138                     {
139                         char *pStart, *pEnd;
140                         HWND hwnd;
141 
142                         hData = DdeClientTransaction(NULL, 0, hConv, hszItem,
143                           CF_TEXT, XTYP_REQUEST, 1000, NULL);
144                         if (hData)
145                         {
146                             pStart = DdeAccessData(hData, NULL);
147                         
148                             ++pStart;
149                             while (*pStart != '\"')
150                                 ++pStart;
151                             pStart += 3;
152                             pEnd = pStart;
153                             while (*pEnd != '\"')
154                                 ++pEnd;
155                             *pEnd = 0;
156 
157                             hwnd = FindWindowByTitle(pStart);
158                             if (hwnd)
159                             {
160                                 if (IsIconic(hwnd))
161                                     ShowWindow(hwnd, SW_RESTORE);
162                                 SetForegroundWindow(hwnd);
163                             }
164 
165                             DdeUnaccessData(hData);
166                         }
167 
168                         DdeDisconnect(hConv);
169                     }
170                 }
171                 if (hszItem)
172                     DdeFreeStringHandle(idInst, hszItem);
173             }
174             if (hszTopic)
175                 DdeFreeStringHandle(idInst, hszTopic);
176             if (hszService)
177                 DdeFreeStringHandle(idInst, hszService);
178             DdeUninitialize(idInst);
179         }
180     }
181     free(lpszURLExec);
182     free(lpszTopic);
183     free(lpszApplication);
184     free(lpszCommand);
185 
186     SetCursor(hcurOld);
187 } 


Listing Two

1  // FindWin.c -- written by Bob Lord 3/96
2  
3  #include <windows.h>
4  
5  static HWND hwndFound;
6  
7  static BOOL CALLBACK EnumWindowsProc(HWND hwnd, LPARAM lParam)
8  {
9      char szWindowTitle[256];
10     unsigned length;
11 
12     length = lstrlen((char *)lParam) + 1;
13     GetWindowText(hwnd, szWindowTitle, length);
14     if (lstrcmp((char *)(LPCSTR)lParam, szWindowTitle) == 0)
15     {
16         hwndFound = hwnd;
17         return FALSE;
18     }
19     return TRUE;
20 }
21 
22 HWND FindWindowByTitle(LPCSTR lpszTitle)
23 {
24     hwndFound = 0;
25     EnumWindows(EnumWindowsProc, (LPARAM)lpszTitle);
26     return hwndFound;
27 }