How to open URLs with default applications in macOS and Windows

 I'm currently updating an old Delphi 5 Desktop VCL application to to Delphi 11.3 FMX. And one of the capabilities I want to provide is the ability to launch several webpages from within the application. I want to place a link in the main menu to my YouTube channel so customers can easily get to product videos. And there's also a link to my website in the Help > About box.

It was fairly straightforward the last time I did this using VCL because all I had to worry about was the Windows side of things. However, because I want this application to run on both Windows and macOS it presented a challenge.

The Delphi IDE won't recognize the Macapi namespace unless the target is set to MacOS 64-bit

Harry Stahl covers the COCOA API on pages 98-99 of his book Cross-Platform Development with Delphi. He also gives an example of how to use the NSWorkspace object of  Macapi.Appkit. However, he doesn't show how to setup the uses clause.

I also found a fantastic reference on stackoverflow by David Heffernan that was written in 2015. However, there are two issues with Heffernan's if you are looking for a complete answer:

1. There is a reference to a blog post by Malcolm Groves called Opening files and URLs in default applications in OS X which is no longer available or accessible.
2. The example doesn't tell you you need to target the MacOS 64-bit platform before the IDE will recognize Macapi namespace..

The Delphi IDE won't recognize the Macapi namespace unless the target is set to MacOS 64-bit. Shame on me for not reading up on the Embarcadero docs. Wrapping my head around how to use the  {$IFDEF MSWindows} and the {$IFDEF MACOS} was a little tricky But I eventually caught on. 

After a couple hours of going back and forth with code that worked for Windows but didn't work for macOS. And code that worked for macOS but didn't work for Windows, I finally got Heffernan's example to work.

The next step was to extract the code out of the main form and place it into it's own unit. And that is the code I'm sharing with you today. I hope you find this helpful. 

Video demonstration of the below source code

Here is the source code:

Unit1.fmx

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Goto Website'
  ClientHeight = 238
  ClientWidth = 478
  Position = ScreenCenter
  FormFactor.Width = 320
  FormFactor.Height = 480
  FormFactor.Devices = [Desktop]
  DesignerMasterStyle = 0
  object Text1: TText
    AutoSize = True
    Cursor = crHandPoint
    Position.X = 116.000000000000000000
    Position.Y = 83.000000000000000000
    Size.Width = 246.078125000000000000
    Size.Height = 31.921875000000000000
    Size.PlatformDefault = False
    Text = 'https://zilchworks.com'
    TextSettings.Font.Size = 24.000000000000000000
    TextSettings.FontColor = claMediumblue
    OnClick = Text1Click
    OnMouseEnter = Text1MouseEnter
    OnMouseLeave = Text1MouseLeave
  end
end

Unit1.pas

unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.Objects;

type
  TForm1 = class(TForm)
    Text1: TText;
    procedure Text1MouseEnter(Sender: TObject);
    procedure Text1MouseLeave(Sender: TObject);
    procedure Text1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

uses
  u.OpenURL;

{ TForm1 }

procedure TForm1.Text1Click(Sender: TObject);
begin
  GotoWebsite(Text1.Text);
end;

procedure TForm1.Text1MouseEnter(Sender: TObject);
begin
  Text1.Font.Style :=  Text1.Font.Style + [TFontStyle.fsUnderline];
end;

procedure TForm1.Text1MouseLeave(Sender: TObject);
begin
  Text1.Font.Style :=  Text1.Font.Style - [TFontStyle.fsUnderline];
end;

end.

u.OpenUrl.pas

{
+-------------------------------------------------------------------------------
¦ Filename:    u.OpenURL Unit
¦ Author:      Michael J. Riley
¦ Website:     https://zilchworks.com
¦ YouTube:     https://www.youtube.com/@CapeCodGunny
¦ Copyright:   © 2023-2024 by Michael J. Riley. All Rights Reserved.
+-------------------------------------------------------------------------------
¦ Purpose:     Opens a url using the default browser on the users system.
¦
¦ OS:          Windows, macOS
+-------------------------------------------------------------------------------
¦ Developer References:
¦
¦ Book:        Cross-Platform Development with Delphi 10.2 & FireMonkey
¦ Author:      Harry Stahl
¦ ISBN:        https://isbnsearch.org/isbn/9781549545764
¦ Notes:       See pages 98-99.
¦
¦ Websites:    https://stackoverflow.com/q/28858392/195983
¦              https://stackoverflow.com/a/28859000/195983
+-------------------------------------------------------------------------------
¦ DISCLAIMER:
¦
¦ This source code is provided "as is" and without any warranty. Use it at your
¦ own risk. The author(s) make no guarantees or assurances regarding the
¦ correctness or functionality of the code, and disclaim any liability for
¦ damages resulting from its use.
¦
¦ It is advisable to thoroughly review and test the code before deploying it in
¦ any production environment.
¦
¦ By using this code, you agree to these terms and acknowledge that any issues
¦ arising from its use are solely your responsibility.
+-------------------------------------------------------------------------------
}
unit u.OpenURL;

interface

{$IFDEF MSWindows}
uses
  Winapi.ShellAPI,
  Winapi.Windows;
{$ENDIF}

{$IFDEF MACOS}
uses
  Macapi.AppKit,
  Macapi.Foundation,
  Macapi.Helpers;

  procedure macOSGotoWebsite(URL: string);
{$ENDIF}

  procedure GotoWebsite(URL: string);

implementation


procedure GotoWebsite(URL: string);
begin
  {$IFDEF MSWindows}
  ShellExecute(GetDesktopWindow, 'open', PChar(URL), '', '', SW_SHOWNORMAL)
  {$ENDIF}
  {$IFDEF MACOS}
  macOSGotoWebsite(URL);
  {$ENDIF}
end;

{$IFDEF MACOS}
procedure macOSGotoWebsite(URL: string);
var
  macURL: NSURL;
  macWorkspace: NSWorkspace;
begin
  macURL := TNSURL.Wrap(TNSURL.OCClass.URLWithString(StrToNSStr(URL)));
  macWorkspace := TNSWorkspace.Wrap(TNSWorkspace.OCClass.sharedWorkspace);
  macWorkspace.openURL(macURL);
end;
{$ENDIF}

end.

Enjoy!

Gunny Mike
https://zilchworks.com