#0 enh - Gzipping main bundle on the fly

rsanchez

2017-06-08 d00705286218a5f501ab18bc8a50ec22f043b8b7

#0 enh - Gzipping main bundle on the fly

 securis/src/main/java/net/curisit/securis/GzipFilter.java
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@@ -10,13 +10,16 @@
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 import javax.servlet.ServletRequest;
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 import javax.servlet.ServletResponse;
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 import javax.servlet.annotation.WebFilter;
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+import javax.servlet.http.HttpServletRequest;
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 import javax.servlet.http.HttpServletResponse;
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 import org.apache.logging.log4j.LogManager;
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 import org.apache.logging.log4j.Logger;
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+import net.curisit.securis.utils.GZipServletResponseWrapper;
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+
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 @ApplicationScoped
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-@WebFilter(urlPatterns = "*.gz")
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+@WebFilter(urlPatterns = "*.js")
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 public class GzipFilter implements Filter {
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 	@SuppressWarnings("unused")
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@@ -27,12 +30,24 @@
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 	}
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 	@Override
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-	public void doFilter(ServletRequest sreq, ServletResponse sres, FilterChain fc) throws IOException, ServletException {
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-		//HttpServletRequest req = (HttpServletRequest) sreq;
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-		HttpServletResponse res = (HttpServletResponse) sres;
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-		res.addHeader("Content-Encoding", "gzip");
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-		// LOG.info("Content served as gzip: {}", req.getRequestURI());
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-		fc.doFilter(sreq, sres);
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+	public void doFilter(ServletRequest sreq, ServletResponse sres, FilterChain chain) throws IOException, ServletException {
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+		HttpServletRequest httpRequest = (HttpServletRequest) sreq;
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+		HttpServletResponse httpResponse = (HttpServletResponse) sres;
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+
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+		if (acceptsGZipEncoding(httpRequest)) {
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+			httpResponse.addHeader("Content-Encoding", "gzip");
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+			GZipServletResponseWrapper gzipResponse = new GZipServletResponseWrapper(httpResponse);
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+			chain.doFilter(sreq, gzipResponse);
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+			gzipResponse.close();
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+		} else {
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+			chain.doFilter(sreq, sres);
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+		}
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+	}
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+
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+	private boolean acceptsGZipEncoding(HttpServletRequest httpRequest) {
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+		String acceptEncoding = httpRequest.getHeader("Accept-Encoding");
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+
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+		return acceptEncoding != null && acceptEncoding.indexOf("gzip") != -1;
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 	}
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 	@Override
 securis/src/main/java/net/curisit/securis/utils/GZipServletResponseWrapper.java
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@@ -0,0 +1,139 @@
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+package net.curisit.securis.utils;
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+
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+import java.io.IOException;
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+import java.io.OutputStreamWriter;
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+import java.io.PrintWriter;
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+import java.util.zip.GZIPOutputStream;
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+
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+import javax.servlet.ServletOutputStream;
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+import javax.servlet.WriteListener;
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+import javax.servlet.http.HttpServletResponse;
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+import javax.servlet.http.HttpServletResponseWrapper;
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+
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+public class GZipServletResponseWrapper extends HttpServletResponseWrapper {
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+
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+	private GZIPServletOutputStream gzipOutputStream = null;
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+	private PrintWriter printWriter = null;
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+
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+	public GZipServletResponseWrapper(HttpServletResponse response) throws IOException {
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+		super(response);
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+	}
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+
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+	public void close() throws IOException {
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+
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+		//PrintWriter.close does not throw exceptions.
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+		//Hence no try-catch block.
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+		if (this.printWriter != null) {
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+			this.printWriter.close();
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+		}
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+
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+		if (this.gzipOutputStream != null) {
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+			this.gzipOutputStream.close();
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+		}
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+	}
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+
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+	/**
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+	 * Flush OutputStream or PrintWriter
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+	 *
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+	 * @throws IOException
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+	 */
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+
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+	@Override
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+	public void flushBuffer() throws IOException {
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+
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+		//PrintWriter.flush() does not throw exception
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+		if (this.printWriter != null) {
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+			this.printWriter.flush();
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+		}
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+
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+		IOException exception1 = null;
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+		try {
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+			if (this.gzipOutputStream != null) {
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+				this.gzipOutputStream.flush();
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+			}
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+		} catch (IOException e) {
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+			exception1 = e;
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+		}
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+
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+		IOException exception2 = null;
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+		try {
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+			super.flushBuffer();
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+		} catch (IOException e) {
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+			exception2 = e;
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+		}
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+
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+		if (exception1 != null)
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+			throw exception1;
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+		if (exception2 != null)
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+			throw exception2;
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+	}
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+
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+	@Override
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+	public ServletOutputStream getOutputStream() throws IOException {
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+		if (this.printWriter != null) {
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+			throw new IllegalStateException("PrintWriter obtained already - cannot get OutputStream");
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+		}
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+		if (this.gzipOutputStream == null) {
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+			this.gzipOutputStream = new GZIPServletOutputStream(getResponse().getOutputStream());
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+		}
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+		return this.gzipOutputStream;
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+	}
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+
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+	@Override
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+	public PrintWriter getWriter() throws IOException {
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+		if (this.printWriter == null && this.gzipOutputStream != null) {
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+			throw new IllegalStateException("OutputStream obtained already - cannot get PrintWriter");
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+		}
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+		if (this.printWriter == null) {
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+			this.gzipOutputStream = new GZIPServletOutputStream(getResponse().getOutputStream());
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+			this.printWriter = new PrintWriter(new OutputStreamWriter(this.gzipOutputStream, getResponse().getCharacterEncoding()));
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+		}
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+		return this.printWriter;
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+	}
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+
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+	@Override
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+	public void setContentLength(int len) {
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+		//ignore, since content length of zipped content
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+		//does not match content length of unzipped content.
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+	}
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+
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+	private static class GZIPServletOutputStream extends ServletOutputStream {
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+		private final ServletOutputStream servletOutputStream;
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+		private final GZIPOutputStream gzipStream;
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+
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+		public GZIPServletOutputStream(ServletOutputStream servletOutputStream) throws IOException {
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+			this.servletOutputStream = servletOutputStream;
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+			this.gzipStream = new GZIPOutputStream(servletOutputStream);
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+		}
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+
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+		@Override
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+		public boolean isReady() {
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+			return this.servletOutputStream.isReady();
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+		}
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+
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+		@Override
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+		public void setWriteListener(WriteListener writeListener) {
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+			this.servletOutputStream.setWriteListener(writeListener);
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+		}
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+
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+		@Override
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+		public void write(int b) throws IOException {
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+			this.gzipStream.write(b);
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+		}
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+
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+		@Override
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+		public void close() throws IOException {
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+			this.gzipStream.close();
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+		}
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+
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+		@Override
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+		public void flush() throws IOException {
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+			this.gzipStream.flush();
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+		}
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+
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+		public void finish() throws IOException {
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+			this.gzipStream.finish();
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+		}
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+	}
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+
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+}
 securis/src/main/webapp/WEB-INF/web.xml
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@@ -60,7 +60,7 @@
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     </filter>    
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     <filter-mapping>
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         <filter-name>GzipFilter</filter-name>
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-        <url-pattern>*.gz</url-pattern>
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+        <url-pattern>/main-bundle.js</url-pattern>
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     </filter-mapping>
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 	<filter>
 securis/src/main/webapp/index.jsp
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@@ -11,7 +11,7 @@
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     <script src="jspm.browser.js"></script>
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     <script src="jspm.config.js"></script>
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-    <script src="main-bundle.js.gz"></script>
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+    <script src="main-bundle.js"></script>
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     <script>
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       System.import('src/main.js').catch(function(err){ console.error(err); });
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     </script>