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Add support for JPEG, GIF images from chart server; can request chart.png / chart.jpg / chart.gif now

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This commit is contained in:
Sean Owen 2017-05-22 13:45:51 +01:00
parent 713c5bb001
commit 11f5278aa7
1 changed files with 36 additions and 5 deletions
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41
zxingorg/src/main/java/com/google/zxing/web/ChartServlet.java
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@ -38,16 +38,19 @@ 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.
* 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")
@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;
@ -64,7 +67,7 @@ public final class ChartServlet extends HttpServlet {
doEncode(request, response, true);
}
private static void doEncode(ServletRequest request, HttpServletResponse response, boolean isPost)
private static void doEncode(HttpServletRequest request, HttpServletResponse response, boolean isPost)
throws IOException {
ChartServletRequestParameters parameters;
@ -95,11 +98,39 @@ public final class ChartServlet extends HttpServlet {
return;
}
String requestURI = request.getRequestURI();
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 pngOut = new ByteArrayOutputStream();
MatrixToImageWriter.writeToStream(matrix, "PNG", pngOut);
MatrixToImageWriter.writeToStream(matrix, imageFormat, pngOut);
byte[] pngData = pngOut.toByteArray();
response.setContentType("image/png");
response.setContentType(contentType);
response.setContentLength(pngData.length);
response.setHeader("Cache-Control", "public");
response.getOutputStream().write(pngData);