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Internet

Reads the connection state, combines and cleans URLs, and finds browsers and mail.

The connection and URL functions are thin covers over WinINet, the Internet layer of Windows, returning a ustring or a plain answer instead of filling buffers. The URL functions work on text alone and never go on the network. The browser and mail functions read what is registered on this machine; none of them starts a program.

Importing

#import "sys/win"
using win

Example

A console program that reports the connection, the default browser and a URL built from a base and a relative link:

#import "sys/win"
using win

if InternetGetConnectedState() then
    print "online through "; InternetGetConnectionName()
else
    print "offline"
end if

dim browser as ustring = GetDefaultBrowserName()
if len( browser ) then print "default browser: "; browser else print "no default browser"
print "Edge version: "; GetEdgeVersion()

print InternetCombineUrl( "https://example.com/docs/page.html", "../img/logo.png" )
' https://example.com/img/logo.png

Functions

Function	Does
InternetAttemptConnect	Asks Windows to make a connection to the Internet.
InternetCheckConnection	Tells whether a server can be reached.
InternetCanonicalizeUrl	Escapes unsafe characters in a URL and resolves .. and ..
InternetCombineUrl	Combines a base URL and a relative URL.
InternetGetConnectedState	Tells whether the machine has an Internet connection.
InternetGetConnectionDescription	Returns flags describing the connection.
InternetGetConnectionName	Returns the name of the connection.
GetEdgeVersion	Returns the version of Microsoft Edge.
GetFirefoxVersion	Returns the version of Firefox.
GetChromeVersion	Returns the version of Google Chrome.
GetDefaultBrowserName	Returns the program name of the default browser.
GetDefaultBrowserPath	Returns the full path of the default browser.
GetDefaultMailClientPath	Returns the full path of the default mail program.
GetDefaultMailClientName	Returns the program name of the default mail program.

Reference

InternetAttemptConnect

function InternetAttemptConnect overload() as DWORD

Asks Windows to connect to the Internet, dialling a modem connection if that is how the machine connects; a machine that is already online answers at once. The Windows function, which takes a reserved argument, is still there with one argument.

Returns ERROR_SUCCESS (0) when a connection is there or was made, otherwise a Windows error code.

Example

if InternetAttemptConnect() = ERROR_SUCCESS then print "you can connect to the Internet"

Microsoft Learn: InternetAttemptConnect

InternetCheckConnection

function InternetCheckConnection overload( byval pwszUrl as wstring ptr ) as boolean

Tries to reach the server of a URL (FLAG_ICC_FORCE_CONNECTION): only the host is used, not the page. The call waits for the answer, which can take several seconds when the server does not respond. The Windows function, with a flags argument and a reserved one, is still there.

Parameter	Meaning
pwszUrl	A URL such as "https://example.com/".

Returns true when the server could be reached; on failure false, and GetLastError() says why.

Example

if InternetCheckConnection( "https://example.com/" ) then print "the server answers"

Microsoft Learn: InternetCheckConnectionW

InternetCanonicalizeUrl

function InternetCanonicalizeUrl overload( byval pwszUrl as wstring ptr, byval dwFlags as DWORD = 0 ) as ustring

Puts a URL into its standard form: unsafe characters and spaces become % escape sequences, and .. and . segments are resolved. "http://example.com/a b/../c.html" gives http://example.com/c.html; "http://example.com/my file.html" gives http://example.com/my%20file.html.

The text does not have to be a URL: "not a url" comes back as not%20a%20url.

Parameter	Meaning
pwszUrl	The URL.
dwFlags	ICU_* flags. 0 escapes and resolves. ICU_DECODE or ICU_NO_ENCODE turns %20 back into a space; ICU_DECODE alone decodes and then escapes again. ICU_NO_META leaves .. and . alone.

Returns the URL, or "" when it cannot be processed.

Example

print InternetCanonicalizeUrl( "http://example.com/a%20b", ICU_DECODE or ICU_NO_ENCODE )   ' http://example.com/a b

Microsoft Learn: InternetCanonicalizeUrlW

InternetCombineUrl

function InternetCombineUrl overload( byval pwszBaseUrl as wstring ptr, byval pwszRelativeUrl as wstring ptr, byval dwFlags as DWORD = 0 ) as ustring

Resolves a relative URL, such as a link found in a page, against the URL of the page, the way a browser does, and returns the result in standard form.

pwszBaseUrl	pwszRelativeUrl	Result
https://example.com/docs/page.html	../img/logo.png	https://example.com/img/logo.png
https://example.com/docs/	/forum/index.php?board=1.0	https://example.com/forum/index.php?board=1.0
https://example.com/docs/	intro page.html	https://example.com/docs/intro%20page.html

Parameter	Meaning
pwszBaseUrl	The URL the link is relative to.
pwszRelativeUrl	The link. A complete URL is returned as it is.
dwFlags	ICU_* flags, as for InternetCanonicalizeUrl.

Returns the combined URL, or "" on failure.

Example

print InternetCombineUrl( "https://example.com/docs/", "intro page.html" )

Microsoft Learn: InternetCombineUrlW

InternetGetConnectedState

function InternetGetConnectedState overload() as boolean

Tells whether the machine has a connection Windows can use to reach the Internet. This is what the network settings say, not a test that a server answers; use InternetCheckConnection for that. The Windows function, which also returns flags, is still there with two arguments.

Returns true when there is a connection.

Example

if InternetGetConnectedState() = false then print "working offline"

Microsoft Learn: InternetGetConnectedState

InternetGetConnectionDescription

function InternetGetConnectionDescription() as DWORD

Returns flags that describe how the machine connects:

Flag	Value	Means
INTERNET_CONNECTION_MODEM	&h01	through a modem
INTERNET_CONNECTION_LAN	&h02	through a local network
INTERNET_CONNECTION_PROXY	&h04	through a proxy server
INTERNET_RAS_INSTALLED	&h10	remote access (dial-up) is installed
INTERNET_CONNECTION_OFFLINE	&h20	the system is in offline mode
INTERNET_CONNECTION_CONFIGURED	&h40	a connection is configured but may not be up

A machine on a local network answered &h12, LAN and remote access installed, when measured.

Returns the flags; 0 when there is no connection.

Example

if InternetGetConnectionDescription() and INTERNET_CONNECTION_PROXY then print "through a proxy"

Microsoft Learn: InternetGetConnectedStateExW

InternetGetConnectionName

function InternetGetConnectionName() as ustring

Returns the name Windows gives the connection: LAN Connection for a local network, or the name of a dial-up entry.

Returns the name, or "" when there is no connection.

Example

print "connected through "; InternetGetConnectionName()

GetEdgeVersion

function GetEdgeVersion() as ustring

Returns the version of Microsoft Edge that the current user runs, as Edge records it in the user's part of the registry: a dotted number such as 154.0.4258.37.

Returns the version, or "" when Edge has not recorded one for this user.

Example

dim edge as ustring = GetEdgeVersion()
if len( edge ) then print "Edge"; val( edge ) ' the major version

Microsoft Learn: RegQueryValueExW

GetFirefoxVersion

function GetFirefoxVersion() as ustring

Returns the version string a machine-wide Firefox installation records in the registry.

Returns the version, or "" when Firefox is not installed for all users.

Example

if len( GetFirefoxVersion() ) = 0 then print "Firefox is not installed"

GetChromeVersion

function GetChromeVersion() as ustring

Returns the version of Google Chrome as Google's updater records it for a machine-wide installation. A copy of Chrome installed for the current user only is not seen.

Returns the version, or "" when no machine-wide Chrome is recorded.

Example

dim chrome as ustring = GetChromeVersion()
if len( chrome ) then print "Chrome "; chrome else print "no machine-wide Chrome"

GetDefaultBrowserName

function GetDefaultBrowserName() as ustring

Returns the program name of the browser that opens http links, without folder or extension: msedge, firefox, chrome.

Returns the name, or "" when no browser is registered.

Example

print "links open in "; GetDefaultBrowserName()

Microsoft Learn: AssocQueryStringW

GetDefaultBrowserPath

function GetDefaultBrowserPath() as ustring

Returns the full path of the program that opens http links, such as C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe.

Returns the path, or "" when no browser is registered.

Example

dim browser as ustring = GetDefaultBrowserPath()
if len( browser ) then ShellExecuteW( NULL, "open", browser, "https://example.com/", NULL, SW_SHOWNORMAL )

GetDefaultMailClientPath

function GetDefaultMailClientPath() as ustring

Returns the full path of the program that opens mailto: links.

Returns the path, or "" when no mail program is registered.

Example

if len( GetDefaultMailClientPath() ) = 0 then print "no mail program is set up"

GetDefaultMailClientName

function GetDefaultMailClientName() as ustring

Returns the program name of the program that opens mailto: links, without folder or extension, such as OUTLOOK or thunderbird, as the file is named on disk.

Returns the name, or "" when no mail program is registered.

Example

print "mail goes through "; GetDefaultMailClientName()

See also

• Category: sys/win
• Common dialogs for the Internet Properties dialog tabs
• CWebView2, the Edge browser control