com.microsoft.azure.servicebus.SharedAccessSignatureTokenProvider Maven / Gradle / Ivy

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Client library for talking to Microsoft Azure Event Hubs.

There is a newer version: 3.3.0

/*
 * Copyright (c) Microsoft. All rights reserved.
 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
 */
package com.microsoft.azure.servicebus;

import java.io.*;
import java.net.*;
import java.nio.charset.*;
import java.security.*;
import java.time.*;
import java.util.*;

import javax.crypto.Mac;
import javax.crypto.spec.*;

public class SharedAccessSignatureTokenProvider
{
	public static String generateSharedAccessSignature(final String keyName, final String sharedAccessKey, final String resource, final Duration tokenTimeToLive)
			throws IOException, NoSuchAlgorithmException, InvalidKeyException
	{
		if (StringUtil.isNullOrWhiteSpace(keyName))
		{
			throw new IllegalArgumentException("keyName cannot be empty");
		}

		if (StringUtil.isNullOrWhiteSpace(sharedAccessKey))
		{
			throw new IllegalArgumentException("sharedAccessKey cannot be empty");
		}

		if (StringUtil.isNullOrWhiteSpace(resource))
		{
			throw new IllegalArgumentException("resource cannot be empty");
		}

		if (tokenTimeToLive.isZero() || tokenTimeToLive.isNegative())
		{
			throw new IllegalArgumentException("tokenTimeToLive has to positive and in the order-of seconds");
		}

		final String utf8Encoding = StandardCharsets.UTF_8.name();
		String expiresOn = Long.toString(Instant.now().getEpochSecond() + tokenTimeToLive.getSeconds());
		String audienceUri = URLEncoder.encode(resource, utf8Encoding);
		String secretToSign =  audienceUri + "\n" + expiresOn;

		final String hashAlgorithm = "HMACSHA256"; 
		Mac hmac = Mac.getInstance(hashAlgorithm);
		byte[] sasKeyBytes = sharedAccessKey.getBytes(utf8Encoding);
		SecretKeySpec finalKey = new SecretKeySpec(sasKeyBytes, hashAlgorithm);
		hmac.init(finalKey);
		byte[] signatureBytes = hmac.doFinal(secretToSign.getBytes(utf8Encoding));
		String signature = Base64.getEncoder().encodeToString(signatureBytes);

		return String.format(Locale.US, "SharedAccessSignature sr=%s&sig=%s&se=%s&skn=%s",
				audienceUri,
				URLEncoder.encode(signature, utf8Encoding),
				URLEncoder.encode(expiresOn, utf8Encoding),
				URLEncoder.encode(keyName, utf8Encoding));
	}
}