HttpServletRequestWrapper, implementation example for setReadListener / isFinished / isReady?

Question

I am trying to adapt an HttpServletRequestWrapper (see How to read InputStream several times ) so that you can read the body of the HTTP Post after using it in the filter. Now I am faced with a problem how to implement ServletInputStream. Starting with specification 3.1, there are new methods that must be implemented.

• isFinished
• isReady
• setReadListener

I am looking for examples or some code on how these methods can be implemented. Any clues?

Answer 1

Implementation Example:

import com.google.common.primitives.Bytes; import javax.servlet.ReadListener; import javax.servlet.ServletInputStream; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import java.util.Arrays; public class AuthenticationRequestWrapper extends HttpServletRequestWrapper { // tag::variables[] private byte[] requestBody = new byte[0]; private boolean bufferFilled = false; // end::variables[] /** - Constructs a request object wrapping the given request. * - @param request The request to wrap - @throws IllegalArgumentException if the request is null */ public AuthenticationRequestWrapper(HttpServletRequest request) { super(request); } // tag::getRequestBody[] public byte[] getRequestBody() throws IOException { if (bufferFilled) { return Arrays.copyOf(requestBody, requestBody.length); } InputStream inputStream = super.getInputStream(); byte[] buffer = new byte[102400]; // 100kb buffer int bytesRead; while ((bytesRead = inputStream.read(buffer)) != -1) { requestBody = Bytes.concat(this.requestBody, Arrays.copyOfRange(buffer, 0, bytesRead)); // <1> } bufferFilled = true; return requestBody; } // end::getRequestBody[] // tag::getInputStream[] @Override public ServletInputStream getInputStream() throws IOException { return new CustomServletInputStream(getRequestBody()); // <1> } // end::getInputStream[] private static class CustomServletInputStream extends ServletInputStream { private ByteArrayInputStream buffer; public CustomServletInputStream(byte[] contents) { this.buffer = new ByteArrayInputStream(contents); } @Override public int read() throws IOException { return buffer.read(); } @Override public boolean isFinished() { return buffer.available() == 0; } @Override public boolean isReady() { return true; } @Override public void setReadListener(ReadListener listener) { throw new RuntimeException("Not implemented"); } } } 

Answer 2

you can check MockHttpServletRequest in spring structure

Source code can be found here.

Since spring is open source with an Apache2 license, you can start with the code and create your own version.