Slim3 GAE/J で request getInputStream の中身がない

Slim3 GAE/Jで request getInputStream の中身がない。
つまり
request.getInputStream().available() が 0 の状態。

これは InputStream がすでに STREAMED だから。

下記の実装および、web.xmlの記述を行い回避できる。

---

BufferedServletInputStream

import java.io.ByteArrayInputStream;
import java.io.IOException;
import javax.servlet.ServletInputStream;

public class BufferedServletInputStream extends ServletInputStream {

    private ByteArrayInputStream inputStream;

    public BufferedServletInputStream(byte[] buffer) {
        this.inputStream = new ByteArrayInputStream(buffer);
    }

    @Override
    public int available() throws IOException {
        return inputStream.available();
    }

    @Override
    public int read() throws IOException {
        return inputStream.read();
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        return inputStream.read(b, off, len);
    }
}

---

BufferedServletRequestWrapper

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

public class BufferedServletRequestWrapper extends HttpServletRequestWrapper {

    private byte[] buffer;

    public BufferedServletRequestWrapper(HttpServletRequest request)
            throws IOException {
        super(request);

        InputStream is = request.getInputStream();
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte buff[] = new byte[1024];
        int read;
        while ((read = is.read(buff)) > 0) {
            baos.write(buff, 0, read);
        }

        this.buffer = baos.toByteArray();
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        return new BufferedServletInputStream(this.buffer);
    }

}

---

StreamFilter

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

public class StreamFilter implements Filter {

    public void destroy() {
        // TODO Auto-generated method stub

    }

    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        System.out.println("doStreamFilter");
        HttpServletRequest req = (HttpServletRequest) request;
        request = new BufferedServletRequestWrapper(req);
        chain.doFilter(request, response);
    }

    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub

    }

}

---

web.xml(フィルタ部のみ)

    <filter>
        <filter-name>streamFilter</filter-name>
        <filter-class>package.StreamFilter</filter-class>
    </filter>
    <filter>
        <filter-name>HotReloadingFilter</filter-name>
        <filter-class>org.slim3.controller.HotReloadingFilter</filter-class>
    </filter>
    <filter>
        <filter-name>DatastoreFilter</filter-name>
        <filter-class>org.slim3.datastore.DatastoreFilter</filter-class>
    </filter>
    <filter>
        <filter-name>FrontController</filter-name>
        <filter-class>org.slim3.controller.FrontController</filter-class>
    </filter>

  <filter-mapping>
    <filter-name>streamFilter</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
        <dispatcher>INCLUDE</dispatcher>
        <dispatcher>ERROR</dispatcher>
    </filter-mapping>
    <filter-mapping>
        <filter-name>HotReloadingFilter</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
    </filter-mapping>
    <filter-mapping>
        <filter-name>DatastoreFilter</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
    </filter-mapping>
    <filter-mapping>
        <filter-name>FrontController</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
        <dispatcher>INCLUDE</dispatcher>
        <dispatcher>ERROR</dispatcher>
    </filter-mapping>

参考

http://blog.honestyworks.jp/blog/archives/162