Java tutorial
/** * Copyright 2012 Nikita Koksharov * * 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 com.corundumstudio.socketio.protocol; import io.netty.buffer.ByteBuf; import io.netty.buffer.ByteBufInputStream; import io.netty.buffer.Unpooled; import io.netty.handler.codec.base64.Base64; import io.netty.util.CharsetUtil; import java.io.IOException; import java.net.URLDecoder; import java.util.LinkedList; import java.util.UUID; import com.corundumstudio.socketio.AckCallback; import com.corundumstudio.socketio.ack.AckManager; import com.corundumstudio.socketio.handler.ClientHead; public class PacketDecoder { private final UTF8CharsScanner utf8scanner = new UTF8CharsScanner(); private final ByteBuf QUOTES = Unpooled.copiedBuffer("\"", CharsetUtil.UTF_8); private final JsonSupport jsonSupport; private final AckManager ackManager; public PacketDecoder(JsonSupport jsonSupport, AckManager ackManager) { this.jsonSupport = jsonSupport; this.ackManager = ackManager; } private boolean isStringPacket(ByteBuf content) { return content.getByte(content.readerIndex()) == 0x0; } // TODO optimize public ByteBuf preprocessJson(Integer jsonIndex, ByteBuf content) throws IOException { String packet = URLDecoder.decode(content.toString(CharsetUtil.UTF_8), CharsetUtil.UTF_8.name()); int startPos = 0; if (jsonIndex != null) { // skip "d=" startPos = 2; /** * double escaping is required for escaped new lines because unescaping of new lines can be done safely on server-side * (c) socket.io.js * * @see https://github.com/Automattic/socket.io-client/blob/1.3.3/socket.io.js#L2682 */ packet = packet.replace("\\\\n", "\\n"); } int splitIndex = packet.indexOf(":"); String len = packet.substring(startPos, splitIndex); Integer length = Integer.valueOf(len); packet = packet.substring(splitIndex + 1, splitIndex + length + 1); packet = new String(packet.getBytes(CharsetUtil.ISO_8859_1), CharsetUtil.UTF_8); return Unpooled.wrappedBuffer(packet.getBytes(CharsetUtil.UTF_8)); } // fastest way to parse chars to int private long readLong(ByteBuf chars, int length) { long result = 0; for (int i = chars.readerIndex(); i < chars.readerIndex() + length; i++) { int digit = ((int) chars.getByte(i) & 0xF); for (int j = 0; j < chars.readerIndex() + length - 1 - i; j++) { digit *= 10; } result += digit; } chars.readerIndex(chars.readerIndex() + length); return result; } private PacketType readType(ByteBuf buffer) { int typeId = buffer.readByte() & 0xF; return PacketType.valueOf(typeId); } private PacketType readInnerType(ByteBuf buffer) { int typeId = buffer.readByte() & 0xF; return PacketType.valueOfInner(typeId); } @Deprecated public Packet decodePacket(String string, UUID uuid) throws IOException { ByteBuf buf = Unpooled.copiedBuffer(string, CharsetUtil.UTF_8); try { return null; } finally { buf.release(); } } private boolean hasLengthHeader(ByteBuf buffer) { for (int i = 0; i < Math.min(buffer.readableBytes(), 10); i++) { byte b = buffer.getByte(buffer.readerIndex() + i); if (b == (byte) ':' && i > 0) { return true; } if (b > 57 || b < 48) { return false; } } return false; } public Packet decodePackets(ByteBuf buffer, ClientHead client) throws IOException { if (isStringPacket(buffer)) { // TODO refactor int headEndIndex = buffer.bytesBefore((byte) -1); int len = (int) readLong(buffer, headEndIndex); ByteBuf frame = buffer.slice(buffer.readerIndex() + 1, len); // skip this frame buffer.readerIndex(buffer.readerIndex() + 1 + len); return decode(client, frame); } else if (hasLengthHeader(buffer)) { // TODO refactor int lengthEndIndex = buffer.bytesBefore((byte) ':'); int lenHeader = (int) readLong(buffer, lengthEndIndex); int len = utf8scanner.getActualLength(buffer, lenHeader); ByteBuf frame = buffer.slice(buffer.readerIndex() + 1, len); if (lenHeader != len) { frame = Unpooled.wrappedBuffer(frame.toString(CharsetUtil.UTF_8).getBytes(CharsetUtil.ISO_8859_1)); } // skip this frame buffer.readerIndex(buffer.readerIndex() + 1 + len); return decode(client, frame); } return decode(client, buffer); } private String readString(ByteBuf frame) { return readString(frame, frame.readableBytes()); } private String readString(ByteBuf frame, int size) { byte[] bytes = new byte[size]; frame.readBytes(bytes); return new String(bytes, CharsetUtil.UTF_8); } private Packet decode(ClientHead head, ByteBuf frame) throws IOException { if ((frame.getByte(0) == 'b' && frame.getByte(1) == '4') || frame.getByte(0) == 4 || frame.getByte(0) == 1) { return parseBinary(head, frame); } PacketType type = readType(frame); Packet packet = new Packet(type); if (type == PacketType.PING) { packet.setData(readString(frame)); return packet; } if (!frame.isReadable()) { return packet; } PacketType innerType = readInnerType(frame); packet.setSubType(innerType); parseHeader(frame, packet, innerType); parseBody(head, frame, packet); return packet; } private void parseHeader(ByteBuf frame, Packet packet, PacketType innerType) { int endIndex = frame.bytesBefore((byte) '['); if (endIndex <= 0) { return; } int attachmentsDividerIndex = frame.bytesBefore(endIndex, (byte) '-'); boolean hasAttachments = attachmentsDividerIndex != -1; if (hasAttachments && PacketType.BINARY_EVENT.equals(innerType)) { int attachments = (int) readLong(frame, attachmentsDividerIndex); packet.initAttachments(attachments); frame.readerIndex(frame.readerIndex() + 1); endIndex -= attachmentsDividerIndex + 1; } if (endIndex == 0) { return; } // TODO optimize boolean hasNsp = frame.bytesBefore(endIndex, (byte) ',') != -1; if (hasNsp) { String nspAckId = readString(frame, endIndex); String[] parts = nspAckId.split(","); String nsp = parts[0]; packet.setNsp(nsp); if (parts.length > 1) { String ackId = parts[1]; packet.setAckId(Long.valueOf(ackId)); } } else { long ackId = readLong(frame, endIndex); packet.setAckId(ackId); } } private Packet parseBinary(ClientHead head, ByteBuf frame) throws IOException { if (frame.getByte(0) == 1) { frame.readByte(); int headEndIndex = frame.bytesBefore((byte) -1); int len = (int) readLong(frame, headEndIndex); ByteBuf oldFrame = frame; frame = frame.slice(oldFrame.readerIndex() + 1, len); oldFrame.readerIndex(oldFrame.readerIndex() + 1 + len); } if (frame.getByte(0) == 'b' && frame.getByte(1) == '4') { frame.readShort(); } else if (frame.getByte(0) == 4) { frame.readByte(); } Packet binaryPacket = head.getLastBinaryPacket(); if (binaryPacket != null) { ByteBuf attachBuf; if (frame.getByte(0) == 'b' && frame.getByte(1) == '4') { attachBuf = frame; } else { attachBuf = Base64.encode(frame); } binaryPacket.addAttachment(Unpooled.copiedBuffer(attachBuf)); frame.readerIndex(frame.readerIndex() + frame.readableBytes()); if (binaryPacket.isAttachmentsLoaded()) { LinkedList<ByteBuf> slices = new LinkedList<ByteBuf>(); ByteBuf source = binaryPacket.getDataSource(); for (int i = 0; i < binaryPacket.getAttachments().size(); i++) { ByteBuf attachment = binaryPacket.getAttachments().get(i); ByteBuf scanValue = Unpooled.copiedBuffer("{\"_placeholder\":true,\"num\":" + i + "}", CharsetUtil.UTF_8); int pos = PacketEncoder.find(source, scanValue); if (pos == -1) { throw new IllegalStateException( "Can't find attachment by index: " + i + " in packet source"); } ByteBuf prefixBuf = source.slice(source.readerIndex(), pos - source.readerIndex()); slices.add(prefixBuf); slices.add(QUOTES); slices.add(attachment); slices.add(QUOTES); source.readerIndex(pos + scanValue.readableBytes()); } slices.add(source.slice()); ByteBuf compositeBuf = Unpooled.wrappedBuffer(slices.toArray(new ByteBuf[slices.size()])); parseBody(head, compositeBuf, binaryPacket); head.setLastBinaryPacket(null); return binaryPacket; } } return new Packet(PacketType.MESSAGE); } private void parseBody(ClientHead head, ByteBuf frame, Packet packet) throws IOException { if (packet.getType() == PacketType.MESSAGE) { if (packet.getSubType() == PacketType.CONNECT || packet.getSubType() == PacketType.DISCONNECT) { packet.setNsp(readString(frame)); } if (packet.getSubType() == PacketType.ACK) { ByteBufInputStream in = new ByteBufInputStream(frame); AckCallback<?> callback = ackManager.getCallback(head.getSessionId(), packet.getAckId()); AckArgs args = jsonSupport.readAckArgs(in, callback); packet.setData(args.getArgs()); } if (packet.getSubType() == PacketType.EVENT || packet.getSubType() == PacketType.BINARY_EVENT) { if (packet.hasAttachments() && !packet.isAttachmentsLoaded()) { packet.setDataSource(Unpooled.copiedBuffer(frame)); frame.readerIndex(frame.readableBytes()); head.setLastBinaryPacket(packet); } else { ByteBufInputStream in = new ByteBufInputStream(frame); Event event = jsonSupport.readValue(packet.getNsp(), in, Event.class); packet.setName(event.getName()); packet.setData(event.getArgs()); } } } } }