org.ardverk.dropwizard.assets.AssetsDirectoryServlet.java Source code

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Here is the source code for org.ardverk.dropwizard.assets.AssetsDirectoryServlet.java

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/*
 * Copyright 2013 Roger Kapsi
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 */

package org.ardverk.dropwizard.assets;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.Charset;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.eclipse.jetty.http.MimeTypes;
import org.eclipse.jetty.io.Buffer;

import com.google.common.base.Charsets;
import com.google.common.net.HttpHeaders;
import com.google.common.net.MediaType;
import com.yammer.dropwizard.assets.AssetServlet;

/**
 * @see AssetServlet
 */
class AssetsDirectoryServlet extends HttpServlet {

    private static final long serialVersionUID = -6282260875091451501L;

    private static final MediaType DEFAULT_MEDIA_TYPE = MediaType.HTML_UTF_8;

    private final AssetsDirectory directory;

    private final MimeTypes mimeTypes;

    private final Charset charset;

    public AssetsDirectoryServlet(AssetsDirectory directory) {
        this(directory, new MimeTypes(), Charsets.UTF_8);
    }

    public AssetsDirectoryServlet(AssetsDirectory directory, MimeTypes mimeTypes, Charset charset) {
        this.directory = directory;
        this.mimeTypes = mimeTypes;
        this.charset = charset;
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String requestURI = request.getRequestURI();

        try {
            AssetsDirectory.Entry entry = directory.getFileEntry(requestURI);

            if (isCurrent(request, entry)) {
                response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
                return;
            }

            response.setDateHeader(HttpHeaders.LAST_MODIFIED, entry.getLastModified());
            response.setHeader(HttpHeaders.ETAG, entry.getETag());

            MediaType mediaType = DEFAULT_MEDIA_TYPE;

            Buffer mimeType = mimeTypes.getMimeByExtension(requestURI);
            if (mimeType != null) {
                try {
                    mediaType = MediaType.parse(mimeType.toString());
                    if (charset != null && mediaType.is(MediaType.ANY_TEXT_TYPE)) {
                        mediaType = mediaType.withCharset(charset);
                    }
                } catch (IllegalArgumentException ignore) {
                }
            }

            response.setContentType(mediaType.type() + "/" + mediaType.subtype());

            if (mediaType.charset().isPresent()) {
                response.setCharacterEncoding(mediaType.charset().get().toString());
            }

            long contentLength = entry.length();
            if (contentLength >= 0L && contentLength < Integer.MAX_VALUE) {
                response.setContentLength((int) contentLength);
            }

            OutputStream out = response.getOutputStream();
            entry.writeTo(out);
            out.flush();

        } catch (FileNotFoundException err) {
            response.sendError(HttpServletResponse.SC_NOT_FOUND);
        }
    }

    /**
     * Returns {@code true} if the client has an up-to-date version of the asset.
     */
    private static boolean isCurrent(HttpServletRequest request, AssetsDirectory.Entry entry) {
        String etag = entry.getETag();
        long lastModified = entry.getLastModified();

        return etag.equals(request.getHeader(HttpHeaders.IF_NONE_MATCH))
                || (request.getDateHeader(HttpHeaders.IF_MODIFIED_SINCE) >= lastModified);
    }
}