nathankerr · July 25, 2025 12:08 · Feb 20, 2017
diff --git a/Info.plist b/Info.plist
@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+    <key>CFBundleExecutable</key>
+    <string>myapp</string>
+    <key>CFBundleIdentifier</key>
+    <string>com.pocketgophers.myapp</string>
+    <key>CFBundleURLTypes</key>
+    <array>
+        <dict>
+            <key>CFBundleURLName</key>
+            <string>com.pocketgophers.myapp</string>
+            <key>CFBundleURLSchemes</key>
+            <array>
+                <string>myapp</string>
+            </array>
+        </dict>
+    </array>
+    <key>CFBundleInfoDictionaryVersion</key>
+    <string>6.0</string>
+    <key>CFBundleName</key>
+    <string>MyApp</string>
+    <key>CFBundlePackageType</key>
+    <string>APPL</string>
+    <key>CFBundleShortVersionString</key>
+    <string>1.0.0</string>
+    <key>CFBundleVersion</key>
+    <string>20</string>
+</dict>
+</plist>
diff --git a/Makefile b/Makefile
@@ -0,0 +1,17 @@
+myapp.app: *.go *.h *.m Makefile Info.plist
+	mkdir -p myapp.app/Contents/MacOS
+	go build -i -o myapp.app/Contents/MacOS/myapp
+	cp Info.plist myapp.app/Contents/Info.plist
+
+.PHONY: open
+open: myapp.app
+	open myapp.app
+
+.PHONY: scheme
+scheme: myapp.app
+	open myapp://hello/world
+
+.PHONY: clean
+clean:
+	rm -rf myapp.app
+
diff --git a/handler.h b/handler.h
@@ -0,0 +1,9 @@
+#import <Foundation/Foundation.h>
+
+extern void HandleURL(char*);
+
+@interface GoPasser : NSObject
++ (void)handleGetURLEvent:(NSAppleEventDescriptor *)event;
+@end
+
+void StartURLHandler(void);
diff --git a/handler.m b/handler.m
@@ -0,0 +1,15 @@
+#include "handler.h"
+
+@implementation GoPasser
++ (void)handleGetURLEvent:(NSAppleEventDescriptor *)event
+{
+	HandleURL([[[event paramDescriptorForKeyword:keyDirectObject] stringValue] UTF8String]);
+}
+@end
+
+void StartURLHandler(void) {
+	NSAppleEventManager *appleEventManager = [NSAppleEventManager sharedAppleEventManager];
+    [appleEventManager setEventHandler:[GoPasser class]
+                           andSelector:@selector(handleGetURLEvent:)
+                         forEventClass:kInternetEventClass andEventID:kAEGetURL];
+}
diff --git a/main.go b/main.go
@@ -0,0 +1,56 @@
+package main
+
+/*
+#cgo CFLAGS: -x objective-c
+#cgo LDFLAGS: -framework Foundation
+#include "handler.h"
+*/
+import "C"
+
+import (
+	"log"
+
+	"github.com/andlabs/ui"
+)
+
+// Sources used to figure this out:
+// Info.plist: https://gist.github.com/chrissnell/db95a3c5ad6ceca4c673e96cca0f7548
+// custom url handler example: http://fredandrandall.com/blog/2011/07/30/how-to-launch-your-macios-app-with-a-custom-url/
+// obj-c example: https://gist.github.com/leepro/016d7d6b61021dfc67daf61771c92b3c
+// note: import .h, not .m
+
+var labelText chan string
+
+func main() {
+	log.SetFlags(log.Lshortfile)
+
+	labelText = make(chan string, 1) // the event handler blocks!, so buffer the channel at least once to get the first message
+	C.StartURLHandler()
+
+	err := ui.Main(func() {
+		greeting := ui.NewLabel("greeting\nline 2")
+		window := ui.NewWindow("Hello", 200, 100, true)
+		window.SetChild(greeting)
+		window.OnClosing(func(*ui.Window) bool {
+			ui.Quit()
+			return true
+		})
+		window.Show()
+
+		go func() {
+			for text := range labelText {
+				ui.QueueMain(func() {
+					greeting.SetText(text)
+				})
+			}
+		}()
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+//export HandleURL
+func HandleURL(u *C.char) {
+	labelText <- C.GoString(u)
+}