Add new endpoint at /w/chart that mimics http://chart.apis.google.com/chart QR code encoder API. To be deployed shortly to zxing.org

git-svn-id: https://zxing.googlecode.com/svn/trunk@2920 59b500cc-1b3d-0410-9834-0bbf25fbcc57

zxingorg/src/main/java/com/google/zxing/web/ChartServlet.java

@@ -0,0 +1,155 @@
+/*
+ * 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 javax.servlet.ServletRequest;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.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.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.
+ *
+ * @author Sean Owen
+ */
+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(ServletRequest 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;
+    }
+
+    ByteArrayOutputStream pngOut = new ByteArrayOutputStream();
+    MatrixToImageWriter.writeToStream(matrix, "PNG", pngOut);
+    byte[] pngData = pngOut.toByteArray();
+
+    response.setContentType("image/png");
+    response.setContentLength(pngData.length);
+    response.setHeader("Cache-Control", "public");
+    response.getOutputStream().write(pngData);
+  }
+
+  private static ChartServletRequestParameters doParseParameters(ServletRequest request, boolean readBody)
+      throws IOException {
+
+    Preconditions.checkArgument("qr".equals(request.getParameter("cht")), "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 = StandardCharsets.UTF_8;
+    if (outputEncodingName != null) {
+      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);
+  }
+
+}

zxingorg/src/main/java/com/google/zxing/web/ChartServletRequestParameters.java

@@ -0,0 +1,75 @@
+/*
+ * 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.zxing.qrcode.decoder.ErrorCorrectionLevel;
+
+import java.nio.charset.Charset;
+
+/**
+ * Parameters parsed from request for {@link ChartServlet}.
+ *
+ * @author Sean Owen
+ */
+final class ChartServletRequestParameters {
+
+  private final int width;
+  private final int height;
+  private final Charset outputEncoding;
+  private final ErrorCorrectionLevel ecLevel;
+  private final int margin;
+  private final String text;
+
+  ChartServletRequestParameters(int width,
+                                int height,
+                                Charset outputEncoding,
+                                ErrorCorrectionLevel ecLevel,
+                                int margin,
+                                String text) {
+    this.width = width;
+    this.height = height;
+    this.outputEncoding = outputEncoding;
+    this.ecLevel = ecLevel;
+    this.margin = margin;
+    this.text = text;
+  }
+
+  int getWidth() {
+    return width;
+  }
+
+  int getHeight() {
+    return height;
+  }
+
+  Charset getOutputEncoding() {
+    return outputEncoding;
+  }
+
+  ErrorCorrectionLevel getEcLevel() {
+    return ecLevel;
+  }
+
+  int getMargin() {
+    return margin;
+  }
+
+  String getText() {
+    return text;
+  }
+
+}

zxingorg/src/main/java/com/google/zxing/web/DecodeServlet.java

@@ -16,7 +16,6 @@
 
 package com.google.zxing.web;
 
-import com.google.common.base.Charsets;
 import com.google.common.collect.Lists;
 import com.google.common.io.Resources;
 import com.google.common.net.HttpHeaders;
@@ -58,6 +57,7 @@ import java.net.MalformedURLException;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URL;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.EnumMap;
@@ -116,7 +116,7 @@ public final class DecodeServlet extends HttpServlet {
     
     try {
       blockedURLSubstrings =
-          Resources.readLines(Resources.getResource("/private/uri-block-substrings.txt"), Charsets.UTF_8);
+          Resources.readLines(Resources.getResource("/private/uri-block-substrings.txt"), StandardCharsets.UTF_8);
     } catch (IOException ioe) {
       throw new ServletException(ioe);
     }
@@ -392,8 +392,8 @@ public final class DecodeServlet extends HttpServlet {
     boolean minimalOutput = fullParameter != null && !Boolean.parseBoolean(fullParameter);
     if (minimalOutput) {
       response.setContentType(MediaType.PLAIN_TEXT_UTF_8.toString());
-      response.setCharacterEncoding(Charsets.UTF_8.name());
-      try (Writer out = new OutputStreamWriter(response.getOutputStream(), Charsets.UTF_8)) {
+      response.setCharacterEncoding(StandardCharsets.UTF_8.name());
+      try (Writer out = new OutputStreamWriter(response.getOutputStream(), StandardCharsets.UTF_8)) {
         for (Result result : results) {
           out.write(result.getText());
           out.write('\n');

zxingorg/src/web/WEB-INF/web.xml

@@ -32,11 +32,20 @@
     <servlet-class>com.google.zxing.web.DecodeServlet</servlet-class>
     <load-on-startup>1</load-on-startup>
   </servlet>
+  <servlet>
+    <servlet-name>ChartServlet</servlet-name>
+    <servlet-class>com.google.zxing.web.ChartServlet</servlet-class>
+    <load-on-startup>1</load-on-startup>
+  </servlet>
 
   <servlet-mapping>
     <servlet-name>DecodeServlet</servlet-name>
     <url-pattern>/w/decode</url-pattern>
   </servlet-mapping>
+  <servlet-mapping>
+    <servlet-name>ChartServlet</servlet-name>
+    <url-pattern>/w/chart</url-pattern>
+  </servlet-mapping>
 
   <welcome-file-list>
     <welcome-file>index.jspx</welcome-file>