org.springframework.boot.devtools.livereload.Frame Maven / Gradle / Ivy
/*
* Copyright 2012-2020 the original author or authors.
*
* 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
*
* https://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.springframework.boot.devtools.livereload;
import java.io.IOException;
import java.io.OutputStream;
import org.springframework.util.Assert;
/**
* A limited implementation of a WebSocket Frame used to carry LiveReload data.
*
* @author Phillip Webb
*/
class Frame {
private static final byte[] NO_BYTES = new byte[0];
private final Type type;
private final byte[] payload;
/**
* Create a new {@link Type#TEXT text} {@link Frame} instance with the specified
* payload.
* @param payload the text payload
*/
Frame(String payload) {
Assert.notNull(payload, "Payload must not be null");
this.type = Type.TEXT;
this.payload = payload.getBytes();
}
Frame(Type type) {
Assert.notNull(type, "Type must not be null");
this.type = type;
this.payload = NO_BYTES;
}
Frame(Type type, byte[] payload) {
this.type = type;
this.payload = payload;
}
Type getType() {
return this.type;
}
byte[] getPayload() {
return this.payload;
}
@Override
public String toString() {
return new String(this.payload);
}
void write(OutputStream outputStream) throws IOException {
outputStream.write(0x80 | this.type.code);
if (this.payload.length < 126) {
outputStream.write(this.payload.length & 0x7F);
}
else {
outputStream.write(0x7E);
outputStream.write(this.payload.length >> 8 & 0xFF);
outputStream.write(this.payload.length & 0xFF);
}
outputStream.write(this.payload);
outputStream.flush();
}
static Frame read(ConnectionInputStream inputStream) throws IOException {
int firstByte = inputStream.checkedRead();
Assert.state((firstByte & 0x80) != 0, "Fragmented frames are not supported");
int maskAndLength = inputStream.checkedRead();
boolean hasMask = (maskAndLength & 0x80) != 0;
int length = (maskAndLength & 0x7F);
Assert.state(length != 127, "Large frames are not supported");
if (length == 126) {
length = ((inputStream.checkedRead()) << 8 | inputStream.checkedRead());
}
byte[] mask = new byte[4];
if (hasMask) {
inputStream.readFully(mask, 0, mask.length);
}
byte[] payload = new byte[length];
inputStream.readFully(payload, 0, length);
if (hasMask) {
for (int i = 0; i < payload.length; i++) {
payload[i] ^= mask[i % 4];
}
}
return new Frame(Type.forCode(firstByte & 0x0F), payload);
}
/**
* Frame types.
*/
enum Type {
/**
* Continuation frame.
*/
CONTINUATION(0x00),
/**
* Text frame.
*/
TEXT(0x01),
/**
* Binary frame.
*/
BINARY(0x02),
/**
* Close frame.
*/
CLOSE(0x08),
/**
* Ping frame.
*/
PING(0x09),
/**
* Pong frame.
*/
PONG(0x0A);
private final int code;
Type(int code) {
this.code = code;
}
static Type forCode(int code) {
for (Type type : values()) {
if (type.code == code) {
return type;
}
}
throw new IllegalStateException("Unknown code " + code);
}
}
}