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/*
* Copyright 2013 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.zxing.web;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableSet;
import com.google.common.io.CharStreams;
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 jakarta.servlet.ServletRequest;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Collection;
import java.util.EnumMap;
import java.util.Locale;
import java.util.Map;
/**
* A reimplementation of the
* <a href="https://google-developers.appspot.com/chart/infographics/docs/qr_codes">
* Google Chart Server's QR code encoder</a>, which is now deprecated. See
* <a href="https://github.com/zxing/zxing/wiki/Chart-Server-Parameters">the chart server
* parameters wiki page</a> for docs.
*
* @author Sean Owen
*/
@WebServlet({"/w/chart", "/w/chart.png", "/w/chart.gif", "/w/chart.jpg", "/w/chart.jpeg"})
public final class ChartServlet extends HttpServlet {
private static final int MAX_DIMENSION = 4096;
private static final Collection<Charset> SUPPORTED_OUTPUT_ENCODINGS = ImmutableSet.<Charset>builder()
.add(StandardCharsets.UTF_8).add(StandardCharsets.ISO_8859_1).add(Charset.forName("Shift_JIS")).build();
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
doEncode(request, response, false);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
doEncode(request, response, true);
}
private static void doEncode(HttpServletRequest request, HttpServletResponse response, boolean isPost)
throws IOException {
ChartServletRequestParameters parameters;
try {
parameters = doParseParameters(request, isPost);
} catch (IllegalArgumentException | NullPointerException e) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, e.toString());
return;
}
Map<EncodeHintType,Object> hints = new EnumMap<>(EncodeHintType.class);
hints.put(EncodeHintType.MARGIN, parameters.getMargin());
if (!StandardCharsets.ISO_8859_1.equals(parameters.getOutputEncoding())) {
// Only set if not QR code default
hints.put(EncodeHintType.CHARACTER_SET, parameters.getOutputEncoding().name());
}
hints.put(EncodeHintType.ERROR_CORRECTION, parameters.getEcLevel());
BitMatrix matrix;
try {
matrix = new QRCodeWriter().encode(parameters.getText(),
BarcodeFormat.QR_CODE,
parameters.getWidth(),
parameters.getHeight(),
hints);
} catch (WriterException we) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, we.toString());
return;
}
String requestURI = request.getRequestURI();
if (requestURI == null) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST);
return;
}
int lastDot = requestURI.lastIndexOf('.');
String imageFormat;
if (lastDot > 0) {
imageFormat = requestURI.substring(lastDot + 1).toUpperCase(Locale.ROOT);
// Special-case jpg -> JPEG
if ("JPG".equals(imageFormat)) {
imageFormat = "JPEG";
}
} else {
imageFormat = "PNG";
}
String contentType;
switch (imageFormat) {
case "PNG":
contentType = "image/png";
break;
case "JPEG":
contentType = "image/jpeg";
break;
case "GIF":
contentType = "image/gif";
break;
default:
throw new IllegalArgumentException("Unknown format " + imageFormat);
}
ByteArrayOutputStream imageOut = new ByteArrayOutputStream(1024);
MatrixToImageWriter.writeToStream(matrix, imageFormat, imageOut);
byte[] imageData = imageOut.toByteArray();
response.setContentType(contentType);
response.setContentLength(imageData.length);
response.setHeader("Cache-Control", "public");
response.getOutputStream().write(imageData);
}
private static ChartServletRequestParameters doParseParameters(ServletRequest request, boolean readBody)
throws IOException {
String chartType = request.getParameter("cht");
Preconditions.checkArgument(chartType == null || "qr".equals(chartType), "Bad type");
String widthXHeight = request.getParameter("chs");
Preconditions.checkNotNull(widthXHeight, "No size");
int xIndex = widthXHeight.indexOf('x');
Preconditions.checkArgument(xIndex >= 0, "Bad size");
int width = Integer.parseInt(widthXHeight.substring(0, xIndex));
int height = Integer.parseInt(widthXHeight.substring(xIndex + 1));
Preconditions.checkArgument(width > 0 && height > 0, "Bad size");
Preconditions.checkArgument(width <= MAX_DIMENSION && height <= MAX_DIMENSION, "Bad size");
String outputEncodingName = request.getParameter("choe");
Charset outputEncoding;
if (outputEncodingName == null) {
outputEncoding = StandardCharsets.UTF_8;
} else {
outputEncoding = Charset.forName(outputEncodingName);
Preconditions.checkArgument(SUPPORTED_OUTPUT_ENCODINGS.contains(outputEncoding), "Bad output encoding");
}
ErrorCorrectionLevel ecLevel = ErrorCorrectionLevel.L;
int margin = 4;
String ldString = request.getParameter("chld");
if (ldString != null) {
int pipeIndex = ldString.indexOf('|');
if (pipeIndex < 0) {
// Only an EC level
ecLevel = ErrorCorrectionLevel.valueOf(ldString);
} else {
ecLevel = ErrorCorrectionLevel.valueOf(ldString.substring(0, pipeIndex));
margin = Integer.parseInt(ldString.substring(pipeIndex + 1));
Preconditions.checkArgument(margin > 0, "Bad margin");
}
}
String text;
if (readBody) {
text = CharStreams.toString(request.getReader());
} else {
text = request.getParameter("chl");
}
Preconditions.checkArgument(text != null && !text.isEmpty(), "No input");
return new ChartServletRequestParameters(width, height, outputEncoding, ecLevel, margin, text);
}
}
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