io.nats.client.support.WebsocketInputStream Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jnats Show documentation
Client library for working with the NATS messaging system.
The newest version!
// Copyright 2022 The NATS 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:
//
// 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 io.nats.client.support;

import io.nats.client.support.WebsocketFrameHeader.OpCode;

import java.io.IOException;
import java.io.InputStream;

public class WebsocketInputStream extends InputStream {
    private byte[] buffer = new byte[WebsocketFrameHeader.MAX_FRAME_HEADER_SIZE];
    private WebsocketFrameHeader header = new WebsocketFrameHeader();
    private InputStream in;
    private byte[] oneByte = new byte[1];

    public WebsocketInputStream(InputStream in) {
        this.in = in;
    }

    @Override
    public int available() throws IOException {
        return in.available();
    }

    @Override
    public void close() throws IOException {
        in.close();
    }

    @Override
    public void mark(int readLimit) {

    }

    @Override
    public boolean markSupported() {
        return false;
    }

    @Override
    public int read(byte[] buffer) throws IOException {
        return read(buffer, 0, buffer.length);
    }

    @Override
    public int read(byte[] buffer, int offset, int length) throws IOException {
        // Just in case we get headers with empty payloads:
        while (0 == header.getPayloadLength()) {
            if (!readHeader()) {
                return -1;
            }
        }
        if (header.getOpCode() == OpCode.CLOSE) {
            // Ignore the websocket close message body:
            in.skip(header.getPayloadLength());
            return -1;
        }
        final long headerPayloadLength = header.getPayloadLength();
        final int payloadLength = Math.min(length, headerPayloadLength > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int)headerPayloadLength);
        length = in.read(buffer, offset, payloadLength);
        if (-1 == length) {
            return length;
        }
        return header.filterPayload(buffer, offset, length);
    }

    @Override
    public int read() throws IOException {
        int result = read(oneByte, 0, 1);
        if (-1 == result) {
            return result;
        }
        return oneByte[0];
    }

    private boolean readHeader() throws IOException {
        int len = 0;
        while (len < 2) {
            int result = in.read(buffer, len, 2 - len);
            if (result < 0) {
                return false;
            }
            len += result;
        }
        int headerSize = WebsocketFrameHeader.size(buffer, 0);
        if (headerSize > 2) {
            while (len < headerSize) {
                int result = in.read(buffer, len, headerSize - len);
                if (result < 0) {
                    return false;
                }
                len += result;
            }
        }
        header.write(buffer, 0, headerSize);
        return true;
    }
}