Parse Error: Invalid character in chunk size when using ResponseWrapper

Question

I'm getting below errors in different conditions when hitting GET request.

a) Parse Error: Invalid character in chunk size when using postman.

b) Illegal or missing hexadecimal sequence in chunked-encoding when using curl.

So, the application uses Spring RestTemplate for api calls, i am using response wrapper in a servlet-filter in order to capture response metrics for eg: body, headers, some meta data etc.

I only get the above errors when using servlet-filter:

Below is my ResponseWrapper.

package com.demo.utils;

import javax.servlet.ServletOutputStream;
import javax.servlet.WriteListener;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import java.io.*;

public class GenericResponseWrapper extends HttpServletResponseWrapper {
    private ServletOutputStream outputStream;
    private PrintWriter writer;
    private FilterServletOutputStream copier;

    public GenericResponseWrapper(HttpServletResponse response) throws IOException {
        super(response);
    }

    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        if (writer != null) {
            throw new IllegalStateException("getWriter() has already been called on this response.");
        }

        if (outputStream == null) {
            outputStream = getResponse().getOutputStream();
            copier = new FilterServletOutputStream(outputStream);
        }

        return copier;
    }

    @Override
    public PrintWriter getWriter() throws IOException {
        if (outputStream != null) {
            throw new IllegalStateException("getOutputStream() has already been called on this response.");
        }

        if (writer == null) {
            copier = new FilterServletOutputStream(getResponse().getOutputStream());
            writer = new PrintWriter(new OutputStreamWriter(copier, getResponse().getCharacterEncoding()), true);
        }

        return writer;
    }

    @Override
    public void flushBuffer() throws IOException {
        if (writer != null) {
            writer.flush();
        } else if (outputStream != null) {
            copier.flush();
        }
    }

    public byte[] getData() {
        if (copier != null) {
            return copier.getData();
        } else {
            return new byte[0];
        }
    }
}

class FilterServletOutputStream extends ServletOutputStream {
    private final OutputStream outputStream;
    private final ByteArrayOutputStream copy;

    public FilterServletOutputStream(OutputStream outputStream) {
        this.outputStream = outputStream;
        this.copy = new ByteArrayOutputStream(1024);
    }

    @Override
    public void write(int b) throws IOException {
        outputStream.write(b);
        copy.write(b);
    }

    public byte[] getData() {
        return copy.toByteArray();
    }

    @Override
    public boolean isReady() {
        return false;
    }

    @Override
    public void setWriteListener(WriteListener writeListener) {

    }
}

Parse Error: Invalid character in chunk size when using ResponseWrapper

0 Answers0