Java tutorial
package io.blobkeeper.server.handler; /* * Copyright (C) 2015 by Denis M. Gabaydulin * * 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. */ import io.blobkeeper.common.domain.ErrorCode; import io.blobkeeper.common.domain.api.ReturnValue; import io.blobkeeper.file.domain.File; import io.blobkeeper.file.service.FileStorage; import io.blobkeeper.file.util.FileUtils; import io.blobkeeper.index.domain.IndexElt; import io.blobkeeper.index.service.IndexService; import io.blobkeeper.server.handler.api.RequestMapper; import io.blobkeeper.server.util.MetadataParser; import io.blobkeeper.server.util.UnClosableFileRegion; import io.netty.channel.*; import io.netty.handler.codec.http.*; import org.asynchttpclient.util.DateUtils; import org.joda.time.DateTime; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.inject.Inject; import javax.inject.Provider; import javax.inject.Singleton; import java.time.Instant; import java.time.ZoneId; import java.time.ZonedDateTime; import java.time.format.DateTimeFormatter; import java.util.Date; import java.util.Locale; import static io.blobkeeper.common.domain.Error.createError; import static io.blobkeeper.common.domain.ErrorCode.*; import static io.blobkeeper.server.util.HttpUtils.NOT_FOUND; import static io.blobkeeper.server.util.HttpUtils.*; import static io.netty.channel.ChannelFutureListener.CLOSE; import static io.netty.handler.codec.http.HttpHeaders.Names.CONNECTION; import static io.netty.handler.codec.http.HttpHeaders.Values.KEEP_ALIVE; import static io.netty.handler.codec.http.HttpHeaders.isKeepAlive; import static io.netty.handler.codec.http.HttpHeaders.setContentLength; import static io.netty.handler.codec.http.HttpMethod.*; import static io.netty.handler.codec.http.HttpResponseStatus.*; import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1; import static io.netty.handler.codec.http.LastHttpContent.EMPTY_LAST_CONTENT; import static java.time.Instant.ofEpochMilli; import static java.time.ZonedDateTime.from; import static java.time.ZonedDateTime.ofInstant; import static org.joda.time.DateTimeZone.UTC; @Singleton @ChannelHandler.Sharable public class FileReaderHandler extends BaseFileHandler<FullHttpRequest> { private static final Logger log = LoggerFactory.getLogger(FileReaderHandler.class); private static final int EXPIRE_YEARS = 1; public static final DateTimeFormatter RFC1123_FORMATTER = DateTimeFormatter.RFC_1123_DATE_TIME .withLocale(Locale.US).withZone(ZoneId.of("GMT")); @Inject private Provider<FileWriterHandler> fileWriterHandlerProvider; @Inject private IndexService indexService; @Inject private FileStorage fileStorage; @Inject private RequestMapper requestMapper; @Override protected void channelRead0(ChannelHandlerContext context, FullHttpRequest request) throws Exception { setContext(); if (request.getMethod() == POST) { context.fireChannelRead(request.copy()); return; } if (request.getMethod() == DELETE) { context.fireChannelRead(request.copy()); return; } addWriterBack(context); if (log.isTraceEnabled()) { log.trace("Request is: {}", request); } if (request.getUri().equals("/favicon.ico")) { sendError(context, HttpResponseStatus.NOT_FOUND, createError(INVALID_REQUEST, "No favorite icon here")); return; } if (!request.getDecoderResult().isSuccess()) { sendError(context, BAD_REQUEST, createError(INVALID_REQUEST, "Strange request given")); return; } if (request.getMethod() != GET) { sendError(context, METHOD_NOT_ALLOWED, createError(INVALID_REQUEST, "Only GET requests are acceptable")); return; } String uri = request.getUri(); final long fileId = getId(uri); final int typeId = getType(uri); if (NOT_FOUND == fileId) { if (tryHandleApiRequest(context, request)) { return; } else { log.error("No id"); sendError(context, BAD_REQUEST, createError(INVALID_REQUEST, "No id")); return; } } if (NOT_FOUND == typeId) { log.error("No type id"); sendError(context, BAD_REQUEST, createError(INVALID_REQUEST, "No type id")); return; } File readerFile = null; IndexElt indexElt; boolean modified; try { log.debug("Id {}", fileId); indexElt = indexService.getById(fileId, typeId); log.debug("Index elt is {}", indexElt); if (null != indexElt) { if (indexElt.isDeleted()) { sendError(context, GONE, createError(DELETED, "File was deleted")); return; } if (indexElt.isAuthRequired()) { String authToken = MetadataParser.getAuthToken(request); if (authToken == null || !indexElt.isAllowed(authToken)) { log.error("You have no permission to see this file {} : token {}", indexElt.getId(), authToken); sendError(context, HttpResponseStatus.FORBIDDEN, createError(ErrorCode.FORBIDDEN, "You have no permission to see this file")); return; } } modified = isModified(indexElt, request); if (modified) { readerFile = fileStorage.getFile(indexElt); } } else { log.error("Index elt not found"); sendError(context, HttpResponseStatus.NOT_FOUND, createError(INVALID_REQUEST, "Index elt not found")); return; } } catch (Exception e) { log.error("Unknown error", e); sendError(context, BAD_GATEWAY, createError(SERVICE_ERROR, "Unknown error")); return; } if (!modified) { sendNotModified(context, indexElt, request); return; } if (null == readerFile) { log.error("Can't find reader file"); sendError(context, BAD_GATEWAY, createError(SERVICE_ERROR, "No reader file")); return; } if (readerFile.getLength() - indexElt.getOffset() < indexElt.getLength()) { String errorMessage = String.format("Reader file length less than index elt %s < %s", readerFile.getLength() - indexElt.getOffset(), indexElt.getLength()); log.error(errorMessage); sendError(context, BAD_GATEWAY, createError(SERVICE_ERROR, errorMessage)); return; } if (FileUtils.isFileEmpty(readerFile, indexElt)) { String errorMessage = String.format("File %s is empty", indexElt); log.error(errorMessage); sendError(context, BAD_GATEWAY, createError(SERVICE_ERROR, errorMessage)); return; } HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK); MetadataParser.copyMetadata(indexElt.getHeaders(), response); addCacheHeaders(response, indexElt); setContentLength(response, indexElt.getLength()); if (isKeepAlive(request)) { response.headers().set(CONNECTION, KEEP_ALIVE); } context.write(response); // Write the content. context.write( new UnClosableFileRegion(readerFile.getFileChannel(), indexElt.getOffset(), indexElt.getLength()), context.voidPromise()); // Write the end marker ChannelFuture lastContentFuture = context.writeAndFlush(EMPTY_LAST_CONTENT); if (!isKeepAlive(request)) { lastContentFuture.addListener(CLOSE); } } private boolean tryHandleApiRequest(ChannelHandlerContext context, FullHttpRequest request) { try { ReturnValue<?> returnValue = requestMapper.getByUri(request.getUri()).handleRequest("{}"); writeResponse(context.channel(), getJson(returnValue), request); return true; } catch (Exception e) { log.error("Can't handle request", e); return false; } } private void addWriterBack(ChannelHandlerContext ctx) { ctx.pipeline().remove("aggregator"); ctx.pipeline().addBefore("reader", "writer", fileWriterHandlerProvider.get()); } private void addCacheHeaders(HttpResponse response, IndexElt indexElt) { ZonedDateTime lastModified = ofInstant(ofEpochMilli(indexElt.getCreated()), ZoneId.of("UTC")); response.headers().add("Last-Modified", lastModified.format(RFC1123_FORMATTER)); response.headers().add("Expires", lastModified.plusYears(EXPIRE_YEARS).format(RFC1123_FORMATTER)); response.headers().add("Cache-Control", "max-age=" + (EXPIRE_YEARS * 365 * 24 * 60 * 60)); } private boolean isModified(IndexElt indexElt, HttpRequest request) { if (request.headers().contains("if-modified-since")) { try { ZonedDateTime lastModified = from( RFC1123_FORMATTER.parse(request.headers().get("if-modified-since"))); ZonedDateTime lastModifiedUTC = lastModified.withZoneSameInstant(ZoneId.of("UTC")); // drop mills from created ZonedDateTime indexCreated = ofInstant(ofEpochMilli(indexElt.getCreated()), ZoneId.of("UTC")); if (indexCreated.toEpochSecond() <= lastModifiedUTC.toEpochSecond()) { return false; } } catch (Exception e) { log.error("Can't parse date " + request.headers().get("if-modified-since"), e); } } return true; } private void sendNotModified(ChannelHandlerContext ctx, IndexElt indexElt, HttpRequest request) { HttpResponse response = new DefaultHttpResponse(HTTP_1_1, NOT_MODIFIED); MetadataParser.copyMetadata(indexElt.getHeaders(), response); response.headers().add("Last-Modified", ofInstant(ofEpochMilli(indexElt.getCreated()), ZoneId.of("UTC")).format(RFC1123_FORMATTER)); if (isKeepAlive(request)) { response.headers().set(CONNECTION, KEEP_ALIVE); } ctx.write(response); // Write the end marker ChannelFuture lastContentFuture = ctx.writeAndFlush(EMPTY_LAST_CONTENT); if (!isKeepAlive(request)) { lastContentFuture.addListener(CLOSE); } } }