jnidzwetzki/bitfinex-v2-wss-api-java

/*******************************************************************************
 *
 *    Copyright (C) 2015-2018 Jan Kristof Nidzwetzki
 *  
 *    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.github.jnidzwetzki.bitfinex.v2.command;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.util.Objects;
import java.util.function.Supplier;

import com.google.common.io.BaseEncoding;
import org.json.JSONObject;

import com.github.jnidzwetzki.bitfinex.v2.BitfinexWebsocketClient;
import com.github.jnidzwetzki.bitfinex.v2.exception.BitfinexCommandException;

public class AuthCommand implements BitfinexCommand {

    /**
     * The used auth algorithm
     */
    private static final String HMAC_SHA1_ALGORITHM = "HmacSHA384";
    
    /**
     * The auth nonce supplier
     */
    private final Supplier<String> authNonceSupplier;
    
    /**
     * Default auth nonce producer
     */
    public static Supplier<String> AUTH_NONCE_PRODUCER_TIMESTAMP = () -> Long.toString(System.currentTimeMillis());
    
    public AuthCommand(final Supplier<String> authNonceSupplier) {
        this.authNonceSupplier = Objects.requireNonNull(authNonceSupplier);
    }

    @Override
    public String getCommand(final BitfinexWebsocketClient client) throws BitfinexCommandException {
        try {
            final String APIKey = client.getConfiguration().getApiKey();
            final String APISecret = client.getConfiguration().getApiSecret();
            final boolean deadManSwitch = client.getConfiguration().isDeadmanSwitchActive();
            
            final String authNonce = authNonceSupplier.get();
            final String authPayload = "AUTH" + authNonce;

            final SecretKeySpec signingKey = new SecretKeySpec(APISecret.getBytes(), HMAC_SHA1_ALGORITHM);
            final Mac mac = Mac.getInstance(HMAC_SHA1_ALGORITHM);
            mac.init(signingKey);
            
            final byte[] encodedBytes = mac.doFinal(authPayload.getBytes());        
            final String authSig = BaseEncoding.base16().encode(encodedBytes);
            
            final JSONObject subscribeJson = new JSONObject();
            subscribeJson.put("event", "auth");
            subscribeJson.put("apiKey", APIKey);
            subscribeJson.put("authSig", authSig.toLowerCase());
            subscribeJson.put("authPayload", authPayload);
            subscribeJson.put("authNonce", authNonce);
            
            if(deadManSwitch) {
                subscribeJson.put("dms", 4);
            }
            
            return subscribeJson.toString();
        } catch (Exception e) {
            throw new BitfinexCommandException(e);
        } 
    }

}