org.apache.lens.server.ui.StaticFileResource.java Source code

Introduction

Here is the source code for org.apache.lens.server.ui.StaticFileResource.java

Source

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.lens.server.ui;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.charset.Charset;
import java.util.concurrent.TimeUnit;

import javax.ws.rs.*;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import org.apache.lens.server.LensServices;
import org.apache.lens.server.api.LensConfConstants;

import org.apache.hadoop.hive.conf.HiveConf;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.io.Files;

/**
 * The Class StaticFileResource.
 */
@Path("/")
public class StaticFileResource {

    // Cache for file content, bound by both size and time
    /** The Constant CONTENT_CACHE. */
    private static final LoadingCache<String, String> CONTENT_CACHE = CacheBuilder.newBuilder().maximumSize(100)
            .expireAfterAccess(10, TimeUnit.MINUTES).build(new CacheLoader<String, String>() {
                String baseDir = null;

                @Override
                public String load(String filePath) throws Exception {
                    if (baseDir == null) {
                        baseDir = LensServices.get().getHiveConf().get(LensConfConstants.SERVER_UI_STATIC_DIR,
                                LensConfConstants.DEFAULT_SERVER_UI_STATIC_DIR);
                    }
                    return loadFile(baseDir, filePath);
                }
            });

    /**
     * Load file.
     *
     * @param baseDir  the base dir
     * @param filePath the file path
     * @return the string
     * @throws IOException Signals that an I/O exception has occurred.
     */
    private static String loadFile(String baseDir, String filePath) throws IOException {
        return Files.toString(new File(baseDir, filePath), Charset.forName("UTF-8"));
    }

    /**
     * Gets the static resource.
     *
     * @param filePath the file path
     * @return the static resource
     */
    @GET
    @Path("/{filePath:.*}")
    public Response getStaticResource(@PathParam("filePath") String filePath) {
        try {
            HiveConf conf = LensServices.get().getHiveConf();
            if (conf.getBoolean(LensConfConstants.SERVER_UI_ENABLE_CACHING,
                    LensConfConstants.DEFAULT_SERVER_UI_ENABLE_CACHING)) {
                return Response.ok(CONTENT_CACHE.get(filePath), getMediaType(filePath)).build();
            } else {
                // This is for dev mode
                String baseDir = conf.get(LensConfConstants.SERVER_UI_STATIC_DIR,
                        LensConfConstants.DEFAULT_SERVER_UI_STATIC_DIR);
                return Response.ok(loadFile(baseDir, filePath), getMediaType(filePath)).build();
            }
        } catch (Exception e) {
            if (e.getCause() instanceof FileNotFoundException || e instanceof FileNotFoundException) {
                throw new NotFoundException("Not Found: " + filePath);
            }
            throw new WebApplicationException("Server error: " + e.getCause(), e);
        }
    }

    /**
     * Gets the media type.
     *
     * @param filePath the file path
     * @return the media type
     */
    private String getMediaType(String filePath) {
        if (filePath == null) {
            return null;
        }

        if (filePath.endsWith(".html")) {
            return MediaType.TEXT_HTML;
        } else if (filePath.endsWith(".js")) {
            return "application/javascript";
        } else if (filePath.endsWith(".css")) {
            return "text/css";
        }
        return null;
    }
}