[darwin] Add support for file input selection (#2209)

This will show a message on the console
"+[CATransaction synchronize] called within transaction"
but there's seem no way to mitigate that. Still everything
works as expected.

v2/internal/frontend/desktop/darwin/WailsContext.h

@@ -29,7 +29,7 @@
 - (void) disableWindowConstraints;
 @end
 
-@interface WailsContext : NSObject <WKURLSchemeHandler,WKScriptMessageHandler,WKNavigationDelegate>
+@interface WailsContext : NSObject <WKURLSchemeHandler,WKScriptMessageHandler,WKNavigationDelegate,WKUIDelegate>
 
 @property (retain) WailsWindow* mainWindow;
 @property (retain) WKWebView* webview;

v2/internal/frontend/desktop/darwin/WailsContext.m

@@ -250,7 +250,8 @@
     }
     
     [self.webview setNavigationDelegate:self];
-    
+    self.webview.UIDelegate = self;
+
     NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
     [defaults setBool:FALSE forKey:@"NSAutomaticQuoteSubstitutionEnabled"];
     
@@ -407,6 +408,25 @@
    [self.webview evaluateJavaScript:script completionHandler:nil];
 }
 
+- (void)webView:(WKWebView *)webView runOpenPanelWithParameters:(WKOpenPanelParameters *)parameters 
+    initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSArray<NSURL *> * URLs))completionHandler {
+    
+    NSOpenPanel *openPanel = [NSOpenPanel openPanel];
+    openPanel.allowsMultipleSelection = parameters.allowsMultipleSelection;
+    if (@available(macOS 10.14, *)) {
+        openPanel.canChooseDirectories = parameters.allowsDirectories;
+    }
+    
+    [openPanel 
+        beginSheetModalForWindow:webView.window
+        completionHandler:^(NSInteger result) {
+            if (result == NSModalResponseOK)
+                completionHandler(openPanel.URLs);
+            else
+                completionHandler(nil);
+        }];
+}
+
 - (void) processURLResponse:(unsigned long long)requestId :(int)statusCode :(NSData *)headersJSON :(NSData *)data {
     NSNumber *key = [NSNumber numberWithUnsignedLongLong:requestId];
 

website/src/pages/changelog.mdx

@@ -22,6 +22,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - The `WindowSetAlwaysOnTop` method is now exposed in the JS runtime. Fixed by @gotid in [PR](https://github.com/wailsapp/wails/pull/2128)
 - The [AssetServer](/docs/reference/options#assetserver) now supports serving the index.html file when requesting a directory. Added by @stffabi in [PR](https://github.com/wailsapp/wails/pull/2110)
 - Added support for WebKit2GTK 2.36+ on Linux. This brings additional features for the [AssetServer](/docs/reference/options#assetserver), like support for HTTP methods and Headers. The app must be compiled with the Go build tag `webkit2_36` to activate support for this features. This also bumps the minimum requirement of WebKit2GTK to 2.36 for your app. Fixed by @stffabi in this [PR](https://github.com/wailsapp/wails/pull/2151)
+- Added support for file input selection on macOS. Added by @stffabi in [PR](https://github.com/wailsapp/wails/pull/2209)
 
 ### Fixed
 - The `noreload` flag in wails dev wasn't applied. Fixed by @stffabi in this [PR](https://github.com/wailsapp/wails/pull/2081)