[bmx] Get default browser path (Windows only) by BlitzSupport [ 1+ years ago ]

[BlitzBot]

Title : Get default browser path (Windows only)
Author : BlitzSupport
Posted : 1+ years ago

Description : Retrieves the path to the Windows default browser; can also check for, and retrieve paths to, a few common browsers by passing specific strings.

Could feasibly be used to determine the 'best' browser available for a specific use, eg. viewing a set of help docs; for instance, I wrote a program intended to open a bunch of tabs in one go, which, weirdly, Internet Explorer still can't do from the command line (no, really), even at version 10! If IE was the default browser, I looked for others, and failing that just gave an error message. (If others were available, I used one of those instead.)

Not heavily tested, but seems to work on both Windows 7 64-bit and a Windows 8 system I don't have direct access to... I would expect it to work on at least 32-bit XP and above.

Code :

Code: BlitzMax

1. ' Some registry references to common browsers:
2.  
3. ' Note that, for most web browsers, this string can be found in the registry under:
4.  
5. ' HKEY_LOCAL_MACHINESOFTWAREClientsStartMenuInternetWEB_BROWSERCapabilitiesFileAssociations.html
6.  
7. ' ... hence it should be fairly easy to check for other browsers by passing this string to GetBrowserPath...
8.  
9. Const IE:String                 = "IE.HTTP"
10. Const FIREFOX:String    = "FirefoxHTML"
11. Const CHROME:String             = "ChromeHTML"
12. Const OPERA:String              = "Opera.HTML"
13. Const OPERANEXT:String  = "Operanext"
14.  
15. Extern "win32"
16.  
17.         Const ERROR_SUCCESS:Int                 = 0
18.  
19.         Const HKEY_CLASSES_ROOT:Int             = $80000000
20.         Const HKEY_CURRENT_USER:Int             = $80000001
21.         Const HKEY_LOCAL_MACHINE:Int    = $80000002
22.         Const HKEY_USERS:Int                    = $80000003
23.         Const HKEY_CURRENT_CONFIG:Int   = $80000005
24.         Const KEY_READ:Int                              = $20019
25.  
26.         Function RegOpenKeyExA (hKey:Int, lpSubKey:Byte Ptr, ulOptions:Int, samDesired:Int, phkResult:Byte Ptr)
27.         Function RegQueryValueExA (hKey:Int, lpValueName:Byte Ptr, lpReserved:Byte Ptr, lpType:Byte Ptr, lpData:Byte Ptr, lpcbData:Byte Ptr)
28.         Function RegCloseKey (hKey:Int)
29.  
30. End Extern
31.  
32. Function GetBrowserPath:String (force:String = "")
33.  
34.         ' Can pass "default" or "" for default browser...
35.        
36.         If Lower (force) = "default"
37.                 force = ""
38.         EndIf
39.        
40.         Local browser:Byte []   ' C string to receive browser path
41.         Local key:Int                   ' Registry key handle (re-used repeatedly)
42.        
43.         ' Find user choice browser ID...
44.        
45.         If RegOpenKeyExA (HKEY_CURRENT_USER, "SoftwareMicrosoftWindowsCurrentVersionExplorerFileExts.htmlUserChoice".ToCString (), 0, KEY_READ, Varptr key) = ERROR_SUCCESS
46.        
47.                 If key
48.                
49.                         Local size:Int
50.                        
51.                         If RegQueryValueExA (key, "Progid".ToCString (), Null, Null, Null, Varptr size) = ERROR_SUCCESS
52.                                 Local classname:Byte [size]
53.                                 RegQueryValueExA (key, "Progid".ToCString (), Null, Null, classname, Varptr size)
54.                         EndIf
55.                
56.                         RegCloseKey key
57.                
58.                         Local browserclassname:String = String.FromCString (classname)
59.                        
60.                         ' Got it, but caller wants to override to retrieve specific browser path...
61.                        
62.                         If force
63.                                 browserclassname = force
64.                         EndIf
65.                        
66.                         ' Use browser ID to get path...
67.                        
68.                         If RegOpenKeyExA (HKEY_CLASSES_ROOT, (String.FromCString (browserclassname) + "shellopencommand").ToCString (), 0, KEY_READ, Varptr key) = ERROR_SUCCESS
69.                                 If RegQueryValueExA (key, "".ToCString (), Null, Null, Null, Varptr size) = ERROR_SUCCESS
70.                                         browser = New Byte [size]
71.                                         RegQueryValueExA (key, "".ToCString (), Null, Null, browser, Varptr size)
72.                                 EndIf
73.                                 RegCloseKey key
74.                         EndIf
75.                        
76.                         Local defaultbrowser:String = String.FromCString (browser)
77.                         Local quote2:Int        ' Used to find second quote in browser string...
78.                        
79.                         ' Usually "path/subpath/browser.exe" plus some extra crap. Just want browser in quotes...
80.                        
81.                         If defaultbrowser
82.                                 quote2 = Instr (defaultbrowser, Chr (34), 2) - 1
83.                                 defaultbrowser = Chr (34) + Mid (defaultbrowser, 2, quote2 - 1) + Chr (34)
84.                         Else
85.                        
86.                                 ' Still nothing? Try generic http handler instead...
87.                                
88.                                 If RegOpenKeyExA (HKEY_CLASSES_ROOT, "httpshellopencommand".ToCString (), 0, KEY_READ, Varptr key) = ERROR_SUCCESS
89.                                         If RegQueryValueExA (key, "".ToCString (), Null, Null, Null, Varptr size) = ERROR_SUCCESS
90.                                                 browser = New Byte [size]
91.                                                 RegQueryValueExA (key, "".ToCString (), Null, Null, browser, Varptr size)
92.                                         EndIf
93.                                         RegCloseKey key
94.                                 EndIf
95.  
96.                                 defaultbrowser = String.FromCString (browser)
97.  
98.                                 ' Strip junk...
99.                                
100.                                 If defaultbrowser
101.                                         quote2 = Instr (defaultbrowser, Chr (34), 2) - 1
102.                                         defaultbrowser = Chr (34) + Mid (defaultbrowser, 2, quote2 - 1) + Chr (34)
103.                                 EndIf
104.  
105.                         EndIf
106.                        
107.                         Return defaultbrowser
108.                        
109.                 EndIf
110.        
111.         EndIf
112.  
113. End Function
114.  
115. ' D E M O . . .
116.  
117. Print ""
118. Print "Checking for default browser..."
119. Print ""
120.  
121.         Print "~tDefault: " + GetBrowserPath () ' or "Default" or ""
122.  
123. Print ""
124. Print "Checking for a few common browsers..."
125. Print ""
126.  
127.         Print "~tInternet Explorer: "   + GetBrowserPath (IE)
128.         Print "~tFirefox: "             + GetBrowserPath (FIREFOX)
129.         Print "~tChrome: "              + GetBrowserPath (CHROME)
130.         Print "~tOpera: "               + GetBrowserPath (OPERA)
131.         Print "~tOpera Next: "          + GetBrowserPath (OPERANEXT)
132.  
133. ' Done!

Comments :


_PJ_(Posted 1+ years ago)

 That first registry key only exists if users have installed, run and selected the "Browser Choice Menu".The http (htt) root class Key also may not exist, or may not even be set to open with a browser, if, for example, someone has set their Open command to run a web-page design program etc.Since this is for Windows only, and I doubt anybody, especially if viewing this on the website noawadays, is using Netscape Navigator, so I think it may be safe to set a default of IE for when these Registry Keys fail.It's also possible for Registry to be locked (via GP or individual permission sets) against applications (or apps run by particular users) to fail.All such failures will return ""


xlsior(Posted 1+ years ago)

 <div class="quote"> That first registry key only exists if users have installed, run and selected the "Browser Choice Menu". </div>Which, FWIW, only exists in the European releases of Windows. The majority of windows users don't get that option.


BlitzSupport(Posted 1+ years ago)

 <div class="quote"> [Browser Choice Menu] only exists in the European releases of Windows. The majority of windows users don't get that option. </div>Ah, you learn something every day! But still, as a fallback...<div class="quote"> The http (htt) root class Key also may not exist, or may not even be set to open with a browser, if, for example, someone has set their Open command to run a web-page design program etc. </div>There must be very few systems where this doesn't exist (I mean, what happens if you click on a web shortcut with no browser specified in either of the above locations?).In cases where it's been set to another type of application, that application must surely 'become' the default web browser?Defaulting to IE isn't necessarily safe, either, of course, as it can be uninstalled by 3rd party programs (or not even installed in the first place depending on the setup in bespoke Windows installers).There's nothing to stop a real-world application asking before opening the default browser (and perhaps saving the answer), or providing an option to disable opening, or offering to run a browser from a given path.I think the above makes for a reasonably wide net, but I of course realise that you can't take anything for granted.