io.getstream.client.okhttp.repo.utils.SignatureUtils Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of stream-repo-okhttp Show documentation
There is a newer version: 2.1.3
package io.getstream.client.okhttp.repo.utils;

import com.google.common.collect.ImmutableList;
import io.getstream.client.exception.StreamClientException;
import io.getstream.client.model.activities.BaseActivity;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SignatureException;

/**
 * Utility class to handle signatures in Stream.io.
 */
public final class SignatureUtils {

    private static final String HMAC_SHA1 = "HmacSHA1";
    public static final String UTF_8 = "UTF-8";

    private SignatureUtils() {
        throw new AssertionError();
    }

    /**
     * Sign all the recipients in the activity.
     *
     * @param secretKey Secret key
     * @param activity  Activity to sign.
     * @throws StreamClientException in case of functional or server-side exceptions
     */
    public static void addSignatureToRecipients(final String secretKey, final BaseActivity activity) throws StreamClientException {
        if (activity.getTo() != null && !activity.getTo().isEmpty()) {
            ImmutableList.Builder recipients = ImmutableList.builder();
            for (String recipient : activity.getTo()) {
                try {
                    recipients.add(String.format("%s %s", recipient, SignatureUtils.calculateHMAC(secretKey, recipient.replace(":", ""))));
                } catch (SignatureException | NoSuchAlgorithmException | InvalidKeyException | UnsupportedEncodingException e) {
                    throw new RuntimeException("Fatal error: cannot create authentication token.");
                }
            }
            activity.setTo(recipients.build());
        }
    }

    /**
     * Calculate HMAC.
     *
     * @param secretKey Secret key
     * @param feedId    Feed Id
     * @return Hash key
     * @throws SignatureException In case of HMAC key generation process exception
     * @throws NoSuchAlgorithmException In case of HMAC key generation process exception
     * @throws InvalidKeyException In case of HMAC key generation process exception
     * @throws UnsupportedEncodingException In case of HMAC key generation process exception
     */
    public static String calculateHMAC(final String secretKey, final String feedId)
            throws SignatureException, NoSuchAlgorithmException, InvalidKeyException, UnsupportedEncodingException {
        SecretKeySpec signingKey = new SecretKeySpec(toSHA1(secretKey), HMAC_SHA1);
        Mac mac = Mac.getInstance(HMAC_SHA1);
        mac.init(signingKey);
        return escapeDigest(Base64.encodeToString(mac.doFinal(feedId.getBytes(UTF_8)), Base64.DEFAULT));
    }

    private static byte[] toSHA1(final String key) throws UnsupportedEncodingException, NoSuchAlgorithmException {
        return MessageDigest.getInstance("SHA-1").digest(key.getBytes(UTF_8));
    }

    private static String escapeDigest(final String digest) {
        return digest.replace("+", "-").replace("\n", "").replace("/", "_").replaceAll("^=+", "").replaceAll("=+$", "");
    }
}