SCM-Manager/scm-webapp/src/main/java/sonia/scm/security/JwtAccessTokenBuilder.java

/**
 * Copyright (c) 2014, Sebastian Sdorra
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. Neither the name of SCM-Manager; nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * http://bitbucket.org/sdorra/scm-manager
 *
 */
package sonia.scm.security;

import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.Maps;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import org.apache.shiro.SecurityUtils;
import org.apache.shiro.subject.Subject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Jwt implementation of {@link AccessTokenBuilder}.
 * 
 * @author Sebastian Sdorra
 * @since 2.0.0
 */
public final class JwtAccessTokenBuilder implements AccessTokenBuilder {

  /**
   * the logger for JwtAccessTokenBuilder
   */
  private static final Logger LOG = LoggerFactory.getLogger(JwtAccessTokenBuilder.class);
  
  private final KeyGenerator keyGenerator; 
  private final SecureKeyResolver keyResolver; 
  private final Set<TokenClaimsEnricher> enrichers;
  
  private String subject;
  private String issuer;
  private long expiresIn = 10l;
  private TimeUnit expiresInUnit = TimeUnit.MINUTES;
  private Scope scope = Scope.empty();
  
  private final Map<String,Object> custom = Maps.newHashMap();
  
  JwtAccessTokenBuilder(
    KeyGenerator keyGenerator, SecureKeyResolver keyResolver, Set<TokenClaimsEnricher> enrichers
  )  {
    this.keyGenerator = keyGenerator;
    this.keyResolver = keyResolver;
    this.enrichers = enrichers;
  }

  @Override
  public JwtAccessTokenBuilder subject(String subject) {
    Preconditions.checkArgument(!Strings.isNullOrEmpty(subject), "null or empty value not allowed");
    this.subject = subject;
    return this;
  }
  
  @Override
  public JwtAccessTokenBuilder custom(String key, Object value) {
    Preconditions.checkArgument(!Strings.isNullOrEmpty(key), "null or empty value not allowed");
    Preconditions.checkArgument(value != null, "null or empty value not allowed");
    this.custom.put(key, value);
    return this;
  }

  @Override
  public JwtAccessTokenBuilder scope(Scope scope) {
    Preconditions.checkArgument(scope != null, "scope can not be null");
    this.scope = scope;
    return this;
  }
  
  @Override
  public JwtAccessTokenBuilder issuer(String issuer) {
    Preconditions.checkArgument(!Strings.isNullOrEmpty(issuer), "null or empty value not allowed");
    this.issuer = issuer;
    return this;
  }

  @Override
  public JwtAccessTokenBuilder expiresIn(long count, TimeUnit unit) {
    Preconditions.checkArgument(count > 0, "expires in must be greater than 0");
    Preconditions.checkArgument(unit != null, "unit can not be null");
    
    this.expiresIn = count;
    this.expiresInUnit = unit;
    
    return this;
  }
  
  private String getSubject(){
    if (subject == null) {
      Subject currentSubject = SecurityUtils.getSubject();
      // TODO find a better way
      currentSubject.checkRole(Role.USER);
      return currentSubject.getPrincipal().toString();
    }
    return subject;
  }

  @Override
  public JwtAccessToken build() {
    String id = keyGenerator.createKey();

    String sub = getSubject();
    
    LOG.trace("create new token {} for user {}", id, subject);
    SecureKey key = keyResolver.getSecureKey(sub);
    
    Map<String,Object> customClaims = new HashMap<>(custom);
    
    // add scope to custom claims
    Scopes.toClaims(customClaims, scope);
    
    // enrich claims with registered enrichers
    enrichers.forEach((enricher) -> {
      enricher.enrich(customClaims);
    });
    
    Date now = new Date();
    long expiration = expiresInUnit.toMillis(expiresIn);
    
    Claims claims = Jwts.claims(customClaims)
      .setSubject(sub)
      .setId(id)
      .setIssuedAt(now)
      .setExpiration(new Date(now.getTime() + expiration));
    
    if ( issuer != null ) {
      claims.setIssuer(issuer);
    }
    
    // sign token and create compact version
    String compact = Jwts.builder()
        .setClaims(claims)
        .signWith(SignatureAlgorithm.HS256, key.getBytes())
        .compact();
    
    return new JwtAccessToken(claims, compact);
  }
  
}