macOS Find Default Application
This article applies to macOS only.
See also: Multiplatform Programming Guide
Overview
From time to time your application may need to determine the user's default application for opening certain content - for example, a web URL or a system file.
Example code which demonstrates how to do this is set out below. Note that these are obviously not the only two content for which you may wish to determine the user's default application, but the same general approach will apply for those other content types.
The alternative example code below demonstrates how to do this for various URL schemes (eg mailto:, http:, https:, sms:, tel:, etc).
Example code
unit Unit1;
{$mode objfpc}{$H+}
{$modeswitch objectivec2}
interface
uses
Classes,
Forms,
Dialogs, // needed for ShowMessage()
StdCtrls, // needed for buttons
CocoaAll, // needed for Cocoa framework (origin the NeXTSTEP libraries)
CocoaUtils; // needed for NSStringToString()
type
{ TForm1 }
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
private
public
end;
var
Form1: TForm1;
implementation
{$R *.lfm}
{ TForm1 }
procedure TForm1.Button1Click(Sender: TObject);
var
contentUrl: NSUrl;
defAppUrl: NSUrl;
defAppName: String;
begin
contentUrl := NSUrl.URLWithString(NSSTR('https://sentinel.sentry.org/'));
defAppUrl := NSWorkspace.sharedWorkspace.URLForApplicationToOpenURL(contentUrl);
// Bundle ID (required)
ShowMessage(NSStringToString(NSBundle.bundleWithURL(defAppUrl).bundleIdentifier));
// Bundle Display Name (optional)
defAppName := NSStringToString(NSBundle.bundleWithURL(defAppUrl).objectForInfoDictionaryKey(NSStr('CFBundleDisplayName').description));
// Bundle Name (conventionally required)
if (defAppName = '') then
defAppName := NSStringToString(NSBundle.bundleWithURL(defAppUrl).objectForInfoDictionaryKey(NSStr('CFBundleName').description));
// Cannot fail :-)
if (defAppName = '') then
defAppName := NSStringToString(defAppUrl.URLByDeletingPathExtension.lastPathComponent);
// Show result
ShowMessage(defAppName);
end;
procedure TForm1.Button2Click(Sender: TObject);
var
contentUrl: NSUrl;
defAppUrl: NSUrl;
defAppName: String;
begin
contentUrl := NSUrl.URLWithString(NSSTR('file:///Users/trev/my_defaults.txt'));
defAppUrl := NSWorkspace.sharedWorkspace.URLForApplicationToOpenURL(contentUrl);
// Bundle ID (required)
ShowMessage(NSStringToString(NSBundle.bundleWithURL(defAppUrl).bundleIdentifier));
// Bundle Display Name (optional)
defAppName := NSStringToString(NSBundle.bundleWithURL(defAppUrl).objectForInfoDictionaryKey(NSStr('CFBundleDisplayName').description));
// Bundle Name (conventionally required)
if (defAppName = '') then
defAppName := NSStringToString(NSBundle.bundleWithURL(defAppUrl).objectForInfoDictionaryKey(NSStr('CFBundleName').description));
// Cannot fail :-)
if (defAppName = '') then
defAppName := NSStringToString(defAppUrl.URLByDeletingPathExtension.lastPathComponent);
// Show result
ShowMessage(defAppName);
end;
end.
Full project source code is available from SourceForge.
Alternative example code for URL schemes
Note that LSGetApplicationForURL was deprecated in macOS 10.10 (Yosemite) in favour of LSCopyDefaultApplicationURLForURL which itself was deprecated in macOS 12 (Monterey), both functions are still working in macOS 12.0.1. There is no example code for LSCopyDefaultApplicationURLForURL because the function is missing from the FPC packages/univint/src/LSInfo.pas file.
unit Unit1;
{$mode objfpc}{$H+}
{$modeswitch objectivec1}
interface
uses
SysUtils, Forms, StdCtrls,
MacOSAll, CocoaAll, CocoaUtils;
type
{ TForm1 }
TForm1 = class(TForm)
Button1: TButton;
Memo1: TMemo;
procedure Button1Click(Sender: TObject);
private
public
end;
var
Form1: TForm1;
implementation
{$R *.lfm}
{ TForm1 }
procedure TForm1.Button1Click(Sender: TObject);
var
myURL: NSURL;
URLRef: CFURLRef;
OSStatus: Integer;
myStr: String;
begin
// Create URL scheme from one of:
// file:///
// file://localhost/
// mailto:
// http:
// https:
// ftp:
// sms:
// tel:
// facetime:
// ... There are probably more.
myURL := NSURL.alloc.initWithString(NSStr('mailto:'));
// Check for default pplication
OSStatus := LSGetApplicationForURL(CFURLRef(myURL), kLSRolesAll, Nil, @URLRef);
// Check for error (eg application not found for URL = -10814)
if(OSStatus <> 0) then
begin
Memo1.Append('LSGetApplicationForURL error status: ' + IntToStr(OSStatus));
Exit;
end;
// Get CFString from CFURLRef, Cast to NSString, Convert to AnsiString
myStr := NSStringToString(NSString(CFURLGetString(URLRef)));
// Output to memo
memo1.Append('LSGetApplicationForURL status: ' + IntToStr(OSStatus)
+ LineEnding + LineEnding + 'Default app: ' + myStr);
// Housekeeping
myURL.release;
end;
end.
Full project source code is available from SourceForge.
See also
- Find the default web browser - cross-platform example.
External links
- Apple: NSWorkspace - available from macOS 10.0
- Apple: NSURL - available from macOS 10.0
- Apple: CFURL, CFURLRef - available from macOS 10.0
- Apple: LSGetApplicationForURL - available from macOS 10.0 - deprecated in macOS 10.10
- Apple: LSCopyDefaultApplicationURLForURL - available from macOS 10.10 - deprecated in macOS 12