Experimental file upload element

Author: hugithordarson

ng-appserver/src/main/java/ng/appserver/elements/NGFileUpload.java

@@ -0,0 +1,77 @@
+package ng.appserver.elements;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+import ng.appserver.NGContext;
+import ng.appserver.NGRequest;
+import ng.appserver.NGRequest.UploadedFile;
+import ng.appserver.NGResponse;
+import ng.appserver.templating.NGDynamicElement;
+import ng.appserver.templating.NGElement;
+import ng.appserver.templating.assications.NGAssociation;
+
+public class NGFileUpload extends NGDynamicElement {
+
+	private final NGAssociation _filenameAssociation;
+	private final NGAssociation _dataAssociation;
+	private final NGAssociation _nameAssociation;
+
+	public NGFileUpload( final String name, final Map<String, NGAssociation> associations, final NGElement contentTemplate ) {
+		super( null, null, null );
+		_filenameAssociation = associations.get( "filename" );
+		_dataAssociation = associations.get( "data" );
+		_nameAssociation = associations.get( "name" );
+	}
+
+	@Override
+	public void appendToResponse( final NGResponse response, final NGContext context ) {
+		response.appendContentString( """
+					<input type="file" name="%s" />
+				""".formatted( name( context ) ) );
+	}
+
+	/**
+	 * @return The name of the field (to use in the HTML code)
+	 */
+	private String name( final NGContext context ) {
+
+		if( _nameAssociation != null ) {
+			return (String)_nameAssociation.valueInComponent( context.component() );
+		}
+
+		return context.elementID().toString();
+	}
+
+	@Override
+	public void takeValuesFromRequest( NGRequest request, NGContext context ) {
+		final String name = name( context );
+		final List<String> valuesFromRequest = request.formValuesForKey( name );
+
+		if( !valuesFromRequest.isEmpty() ) {
+
+			// If multiple form values are present for the same field name, the potential for an error condition is probably high enough to just go ahead and fail.
+			if( valuesFromRequest.size() > 1 ) {
+				throw new IllegalStateException( "The request contains %s form values named '%s'. I can only handle one at a time. The values you sent me are (%s).".formatted( valuesFromRequest.size(), name, valuesFromRequest ) );
+			}
+
+			// If we have a value, that's the filename
+			final String filename = valuesFromRequest.get( 0 );
+
+			_filenameAssociation.setValue( filename, context.component() );
+
+			if( _dataAssociation != null ) {
+				final UploadedFile file = request._uploadedFiles().get( filename );
+
+				try {
+					byte[] data = file.stream().readAllBytes();
+					_dataAssociation.setValue( data, context.component() );
+				}
+				catch( IOException e ) {
+					throw new RuntimeException( e );
+				}
+			}
+		}
+	}
+}

ng-appserver/src/main/java/ng/appserver/templating/NGElementManager.java

@@ -13,6 +13,7 @@
 import ng.appserver.elements.NGBrowser;
 import ng.appserver.elements.NGComponentContent;
 import ng.appserver.elements.NGConditional;
+import ng.appserver.elements.NGFileUpload;
 import ng.appserver.elements.NGForm;
 import ng.appserver.elements.NGGenericContainer;
 import ng.appserver.elements.NGGenericElement;
@@ -254,6 +255,7 @@ public void registerFrameworkElementClasses() {
 		registerElementClass( NGBrowser.class, "browser" );
 		registerElementClass( NGComponentContent.class, "content" );
 		registerElementClass( NGConditional.class, "if" );
+		registerElementClass( NGFileUpload.class, "fileUpload" );
 		registerElementClass( NGForm.class, "form" );
 		registerElementClass( NGString.class, "str" );
 		registerElementClass( NGGenericContainer.class, "container" );