wip

Author: hmottestad

tools/server-spring/src/main/java/org/eclipse/rdf4j/common/webapp/filters/PathFilter.java

@@ -10,16 +10,21 @@
  *******************************************************************************/
 package org.eclipse.rdf4j.common.webapp.filters;
 
-import java.io.CharArrayWriter;
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 
 import javax.servlet.Filter;
 import javax.servlet.FilterChain;
 import javax.servlet.FilterConfig;
 import javax.servlet.ServletException;
+import javax.servlet.ServletOutputStream;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
+import javax.servlet.WriteListener;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpServletResponseWrapper;
@@ -42,39 +47,91 @@ public void destroy() {
 	@Override
 	public void doFilter(ServletRequest req, ServletResponse res, FilterChain filterChain)
 			throws IOException, ServletException {
-		if (req instanceof HttpServletRequest) {
+		if (req instanceof HttpServletRequest && res instanceof HttpServletResponse) {
 			HttpServletRequest request = (HttpServletRequest) req;
 			HttpServletResponse response = (HttpServletResponse) res;
 			String path = request.getContextPath();
 
-			PrintWriter out = response.getWriter();
-			CharResponseWrapper wrapper = new CharResponseWrapper((HttpServletResponse) response);
+			ContentCapturingResponseWrapper wrapper = new ContentCapturingResponseWrapper(response);
 			filterChain.doFilter(request, wrapper);
-			CharArrayWriter caw = new CharArrayWriter();
-			caw.write(wrapper.toString().replace("${path}", path));
-			String result = caw.toString();
-			response.setContentLength(result.length());
-			out.write(result);
+
+			String replaced = wrapper.getCapturedAsString().replace("${path}", path);
+			byte[] body = replaced.getBytes(wrapper.getEncoding());
+
+			response.resetBuffer();
+			response.setContentLength(body.length);
+			response.getOutputStream().write(body);
+		} else {
+			filterChain.doFilter(req, res);
 		}
 	}
 
-	private static class CharResponseWrapper extends HttpServletResponseWrapper {
+	private static class ContentCapturingResponseWrapper extends HttpServletResponseWrapper {
 
-		private final CharArrayWriter output;
+		private final ByteArrayOutputStream content = new ByteArrayOutputStream();
+		private final Charset encoding;
+		private ServletOutputStream outputStream;
+		private PrintWriter writer;
 
-		@Override
-		public String toString() {
-			return output.toString();
+		ContentCapturingResponseWrapper(HttpServletResponse response) {
+			super(response);
+			String characterEncoding = response.getCharacterEncoding();
+			if (characterEncoding == null) {
+				encoding = StandardCharsets.ISO_8859_1;
+			} else {
+				encoding = Charset.forName(characterEncoding);
+			}
 		}
 
-		public CharResponseWrapper(HttpServletResponse response) {
-			super(response);
-			output = new CharArrayWriter();
+		@Override
+		public ServletOutputStream getOutputStream() throws IOException {
+			if (writer != null) {
+				throw new IllegalStateException("getWriter() has already been called on this response.");
+			}
+			if (outputStream == null) {
+				outputStream = new ServletOutputStream() {
+					@Override
+					public boolean isReady() {
+						return true;
+					}
+
+					@Override
+					public void setWriteListener(WriteListener writeListener) {
+						// no-op
+					}
+
+					@Override
+					public void write(int b) throws IOException {
+						content.write(b);
+					}
+				};
+			}
+			return outputStream;
 		}
 
 		@Override
-		public PrintWriter getWriter() {
-			return new PrintWriter(output);
+		public PrintWriter getWriter() throws IOException {
+			if (outputStream != null) {
+				throw new IllegalStateException("getOutputStream() has already been called on this response.");
+			}
+			if (writer == null) {
+				writer = new PrintWriter(new OutputStreamWriter(content, encoding), true);
+			}
+			return writer;
+		}
+
+		String getCapturedAsString() throws IOException {
+			if (writer != null) {
+				writer.flush();
+			}
+			if (outputStream != null) {
+				outputStream.flush();
+			}
+			return content.toString(encoding.name());
+		}
+
+		Charset getEncoding() {
+			return encoding;
 		}
 	}
 }