de.jmens.google.authenticator.QrCodeGenerator Maven / Gradle / Ivy

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package de.jmens.google.authenticator;

import static java.net.URLEncoder.encode;
import static java.text.MessageFormat.format;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.WriterException;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.net.URLEncoder;
import java.nio.file.Paths;
import java.util.EnumMap;
import java.util.Map;
import java.util.Optional;

public class QrCodeGenerator {

	public static Optional generateQRCodePng(String secret, String application, int size) {

		try (final ByteArrayOutputStream output = new ByteArrayOutputStream()) {

			final String text = format(
					"otpauth://totp/{0}?secret={1}",
					encode(application, "UTF-8"),
					encode(secret, "UTF-8")
			);

			final Map hintMap = new EnumMap<>(EncodeHintType.class);
			hintMap.put(EncodeHintType.CHARACTER_SET, "UTF-8");
			hintMap.put(EncodeHintType.MARGIN, 1);
			hintMap.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);

			final QRCodeWriter qrCodeWriter = new QRCodeWriter();
			final BitMatrix bitMatrix = qrCodeWriter.encode(text, BarcodeFormat.QR_CODE, size, size, hintMap);

			MatrixToImageWriter.writeToStream(bitMatrix, "PNG", output);

			return Optional.ofNullable(output.toByteArray());

		} catch (WriterException | IOException e) {
			return Optional.empty();
		}
	}
}