okhttp3.internal.ws.WebSocketReader Maven / Gradle / Ivy
/*
* Copyright (C) 2014 Square, Inc.
*
* 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 okhttp3.internal.ws;
import java.io.EOFException;
import java.io.IOException;
import java.net.ProtocolException;
import java.util.concurrent.TimeUnit;
import okio.Buffer;
import okio.BufferedSource;
import okio.ByteString;
import static java.lang.Integer.toHexString;
import static okhttp3.internal.ws.WebSocketProtocol.B0_FLAG_FIN;
import static okhttp3.internal.ws.WebSocketProtocol.B0_FLAG_RSV1;
import static okhttp3.internal.ws.WebSocketProtocol.B0_FLAG_RSV2;
import static okhttp3.internal.ws.WebSocketProtocol.B0_FLAG_RSV3;
import static okhttp3.internal.ws.WebSocketProtocol.B0_MASK_OPCODE;
import static okhttp3.internal.ws.WebSocketProtocol.B1_FLAG_MASK;
import static okhttp3.internal.ws.WebSocketProtocol.B1_MASK_LENGTH;
import static okhttp3.internal.ws.WebSocketProtocol.CLOSE_NO_STATUS_CODE;
import static okhttp3.internal.ws.WebSocketProtocol.OPCODE_BINARY;
import static okhttp3.internal.ws.WebSocketProtocol.OPCODE_CONTINUATION;
import static okhttp3.internal.ws.WebSocketProtocol.OPCODE_CONTROL_CLOSE;
import static okhttp3.internal.ws.WebSocketProtocol.OPCODE_CONTROL_PING;
import static okhttp3.internal.ws.WebSocketProtocol.OPCODE_CONTROL_PONG;
import static okhttp3.internal.ws.WebSocketProtocol.OPCODE_FLAG_CONTROL;
import static okhttp3.internal.ws.WebSocketProtocol.OPCODE_TEXT;
import static okhttp3.internal.ws.WebSocketProtocol.PAYLOAD_BYTE_MAX;
import static okhttp3.internal.ws.WebSocketProtocol.PAYLOAD_LONG;
import static okhttp3.internal.ws.WebSocketProtocol.PAYLOAD_SHORT;
import static okhttp3.internal.ws.WebSocketProtocol.toggleMask;
/**
* An RFC 6455-compatible WebSocket frame reader.
*
* This class is not thread safe.
*/
final class WebSocketReader {
public interface FrameCallback {
void onReadMessage(String text) throws IOException;
void onReadMessage(ByteString bytes) throws IOException;
void onReadPing(ByteString buffer);
void onReadPong(ByteString buffer);
void onReadClose(int code, String reason);
}
final boolean isClient;
final BufferedSource source;
final FrameCallback frameCallback;
boolean closed;
// Stateful data about the current frame.
int opcode;
long frameLength;
long frameBytesRead;
boolean isFinalFrame;
boolean isControlFrame;
boolean isMasked;
final byte[] maskKey = new byte[4];
final byte[] maskBuffer = new byte[8192];
WebSocketReader(boolean isClient, BufferedSource source, FrameCallback frameCallback) {
if (source == null) throw new NullPointerException("source == null");
if (frameCallback == null) throw new NullPointerException("frameCallback == null");
this.isClient = isClient;
this.source = source;
this.frameCallback = frameCallback;
}
/**
* Process the next protocol frame.
*
*
* - If it is a control frame this will result in a single call to {@link FrameCallback}.
*
- If it is a message frame this will result in a single call to {@link
* FrameCallback#onReadMessage}. If the message spans multiple frames, each interleaved
* control frame will result in a corresponding call to {@link FrameCallback}.
*
*/
void processNextFrame() throws IOException {
readHeader();
if (isControlFrame) {
readControlFrame();
} else {
readMessageFrame();
}
}
private void readHeader() throws IOException {
if (closed) throw new IOException("closed");
// Disable the timeout to read the first byte of a new frame.
int b0;
long timeoutBefore = source.timeout().timeoutNanos();
source.timeout().clearTimeout();
try {
b0 = source.readByte() & 0xff;
} finally {
source.timeout().timeout(timeoutBefore, TimeUnit.NANOSECONDS);
}
opcode = b0 & B0_MASK_OPCODE;
isFinalFrame = (b0 & B0_FLAG_FIN) != 0;
isControlFrame = (b0 & OPCODE_FLAG_CONTROL) != 0;
// Control frames must be final frames (cannot contain continuations).
if (isControlFrame && !isFinalFrame) {
throw new ProtocolException("Control frames must be final.");
}
boolean reservedFlag1 = (b0 & B0_FLAG_RSV1) != 0;
boolean reservedFlag2 = (b0 & B0_FLAG_RSV2) != 0;
boolean reservedFlag3 = (b0 & B0_FLAG_RSV3) != 0;
if (reservedFlag1 || reservedFlag2 || reservedFlag3) {
// Reserved flags are for extensions which we currently do not support.
throw new ProtocolException("Reserved flags are unsupported.");
}
int b1 = source.readByte() & 0xff;
isMasked = (b1 & B1_FLAG_MASK) != 0;
if (isMasked == isClient) {
// Masked payloads must be read on the server. Unmasked payloads must be read on the client.
throw new ProtocolException(isClient
? "Server-sent frames must not be masked."
: "Client-sent frames must be masked.");
}
// Get frame length, optionally reading from follow-up bytes if indicated by special values.
frameLength = b1 & B1_MASK_LENGTH;
if (frameLength == PAYLOAD_SHORT) {
frameLength = source.readShort() & 0xffffL; // Value is unsigned.
} else if (frameLength == PAYLOAD_LONG) {
frameLength = source.readLong();
if (frameLength < 0) {
throw new ProtocolException(
"Frame length 0x" + Long.toHexString(frameLength) + " > 0x7FFFFFFFFFFFFFFF");
}
}
frameBytesRead = 0;
if (isControlFrame && frameLength > PAYLOAD_BYTE_MAX) {
throw new ProtocolException("Control frame must be less than " + PAYLOAD_BYTE_MAX + "B.");
}
if (isMasked) {
// Read the masking key as bytes so that they can be used directly for unmasking.
source.readFully(maskKey);
}
}
private void readControlFrame() throws IOException {
Buffer buffer = new Buffer();
if (frameBytesRead < frameLength) {
if (isClient) {
source.readFully(buffer, frameLength);
} else {
while (frameBytesRead < frameLength) {
int toRead = (int) Math.min(frameLength - frameBytesRead, maskBuffer.length);
int read = source.read(maskBuffer, 0, toRead);
if (read == -1) throw new EOFException();
toggleMask(maskBuffer, read, maskKey, frameBytesRead);
buffer.write(maskBuffer, 0, read);
frameBytesRead += read;
}
}
}
switch (opcode) {
case OPCODE_CONTROL_PING:
frameCallback.onReadPing(buffer.readByteString());
break;
case OPCODE_CONTROL_PONG:
frameCallback.onReadPong(buffer.readByteString());
break;
case OPCODE_CONTROL_CLOSE:
int code = CLOSE_NO_STATUS_CODE;
String reason = "";
long bufferSize = buffer.size();
if (bufferSize == 1) {
throw new ProtocolException("Malformed close payload length of 1.");
} else if (bufferSize != 0) {
code = buffer.readShort();
reason = buffer.readUtf8();
String codeExceptionMessage = WebSocketProtocol.closeCodeExceptionMessage(code);
if (codeExceptionMessage != null) throw new ProtocolException(codeExceptionMessage);
}
frameCallback.onReadClose(code, reason);
closed = true;
break;
default:
throw new ProtocolException("Unknown control opcode: " + toHexString(opcode));
}
}
private void readMessageFrame() throws IOException {
int opcode = this.opcode;
if (opcode != OPCODE_TEXT && opcode != OPCODE_BINARY) {
throw new ProtocolException("Unknown opcode: " + toHexString(opcode));
}
Buffer message = new Buffer();
readMessage(message);
if (opcode == OPCODE_TEXT) {
frameCallback.onReadMessage(message.readUtf8());
} else {
frameCallback.onReadMessage(message.readByteString());
}
}
/** Read headers and process any control frames until we reach a non-control frame. */
void readUntilNonControlFrame() throws IOException {
while (!closed) {
readHeader();
if (!isControlFrame) {
break;
}
readControlFrame();
}
}
/**
* Reads a message body into across one or more frames. Control frames that occur between
* fragments will be processed. If the message payload is masked this will unmask as it's being
* processed.
*/
private void readMessage(Buffer sink) throws IOException {
while (true) {
if (closed) throw new IOException("closed");
if (frameBytesRead == frameLength) {
if (isFinalFrame) return; // We are exhausted and have no continuations.
readUntilNonControlFrame();
if (opcode != OPCODE_CONTINUATION) {
throw new ProtocolException("Expected continuation opcode. Got: " + toHexString(opcode));
}
if (isFinalFrame && frameLength == 0) {
return; // Fast-path for empty final frame.
}
}
long toRead = frameLength - frameBytesRead;
long read;
if (isMasked) {
toRead = Math.min(toRead, maskBuffer.length);
read = source.read(maskBuffer, 0, (int) toRead);
if (read == -1) throw new EOFException();
toggleMask(maskBuffer, read, maskKey, frameBytesRead);
sink.write(maskBuffer, 0, (int) read);
} else {
read = source.read(sink, toRead);
if (read == -1) throw new EOFException();
}
frameBytesRead += read;
}
}
}