Add a GenericTokenChallenge. Remove boilerplate code.

acme4j-client/src/main/java/org/shredzone/acme4j/challenge/DnsChallenge.java

@@ -18,43 +18,27 @@
 import java.security.NoSuchAlgorithmException;
 
 import org.jose4j.base64url.Base64Url;
-import org.shredzone.acme4j.Account;
-import org.shredzone.acme4j.util.ClaimBuilder;
 
 /**
  * Implements the {@code dns-01} challenge.
  *
  * @author Richard "Shred" Körber
  */
-public class DnsChallenge extends GenericChallenge {
+public class DnsChallenge extends GenericTokenChallenge {
     private static final long serialVersionUID = 6964687027713533075L;
 
     /**
      * Challenge type name: {@value}
      */
     public static final String TYPE = "dns-01";
 
-    private String authorization = null;
-
-    /**
-     * Authorizes the {@link Challenge} by signing it with an {@link Account}.
-     *
-     * @param account
-     *            {@link Account} to sign the challenge with
-     */
-    public void authorize(Account account) {
-        if (account == null) {
-            throw new NullPointerException("account must not be null");
-        }
-
-        authorization = getToken() + '.' + Base64Url.encode(jwkThumbprint(account.getKeyPair().getPublic()));
-    }
-
     /**
      * Returns the digest string to be set in the domain's {@code _acme-challenge} TXT
      * record.
      */
     public String getDigest() {
+        assertIsAuthorized();
+
         try {
             MessageDigest md = MessageDigest.getInstance("SHA-256");
             md.update(getAuthorization().getBytes("UTF-8"));
@@ -66,32 +50,9 @@ public String getDigest() {
         }
     }
 
-    @Override
-    public void respond(ClaimBuilder cb) {
-        if (authorization == null) {
-            throw new IllegalStateException("Challenge is not authorized yet");
-        }
-
-        super.respond(cb);
-        cb.put(KEY_TOKEN, getToken());
-        cb.put(KEY_KEY_AUTHORIZATION, getAuthorization());
-    }
-
     @Override
     protected boolean acceptable(String type) {
         return TYPE.equals(type);
     }
 
-    private String getToken() {
-        return get(KEY_TOKEN);
-    }
-
-    private String getAuthorization() {
-        if (authorization == null) {
-            throw new IllegalStateException("Challenge is not authorized yet");
-        }
-
-        return authorization;
-    }
-
 }

acme4j-client/src/main/java/org/shredzone/acme4j/challenge/GenericChallenge.java

@@ -50,8 +50,6 @@ public class GenericChallenge implements Challenge {
     protected static final String KEY_STATUS = "status";
     protected static final String KEY_URI = "uri";
     protected static final String KEY_VALIDATED = "validated";
-    protected static final String KEY_TOKEN = "token";
-    protected static final String KEY_KEY_AUTHORIZATION = "keyAuthorization";
 
     private transient Map<String, Object> data = new HashMap<>();
 

acme4j-client/src/main/java/org/shredzone/acme4j/challenge/GenericTokenChallenge.java

@@ -0,0 +1,100 @@
+/*
+ * acme4j - Java ACME client
+ *
+ * Copyright (C) 2015 Richard "Shred" Körber
+ *   http://acme4j.shredzone.org
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ */
+package org.shredzone.acme4j.challenge;
+
+import org.jose4j.base64url.Base64Url;
+import org.shredzone.acme4j.Account;
+import org.shredzone.acme4j.util.ClaimBuilder;
+
+/**
+ * An extension of {@link GenericChallenge} that handles challenges with a {@code token}
+ * and {@code keyAuthorization}.
+ *
+ * @author Richard "Shred" Körber
+ */
+public class GenericTokenChallenge extends GenericChallenge {
+    private static final long serialVersionUID = 1634133407432681800L;
+
+    protected static final String KEY_TOKEN = "token";
+    protected static final String KEY_KEY_AUTHORIZATION = "keyAuthorization";
+
+    private String authorization;
+
+    /**
+     * Authorizes the {@link Challenge} by signing it with an {@link Account}.
+     *
+     * @param account
+     *            {@link Account} to sign the challenge with
+     */
+    public void authorize(Account account) {
+        if (account == null) {
+            throw new NullPointerException("account must not be null");
+        }
+
+        authorization = computeAuthorization(account);
+    }
+
+    @Override
+    public void respond(ClaimBuilder cb) {
+        assertIsAuthorized();
+
+        super.respond(cb);
+        cb.put(KEY_TOKEN, getToken());
+        cb.put(KEY_KEY_AUTHORIZATION, getAuthorization());
+    }
+
+    /**
+     * Asserts that the challenge was authorized.
+     *
+     * @throws IllegalStateException
+     *             if {@link #authorize(Account)} was not invoked.
+     */
+    protected void assertIsAuthorized() {
+        if (authorization == null) {
+            throw new IllegalStateException("Challenge is not authorized yet");
+        }
+    }
+
+    /**
+     * Gets the token.
+     */
+    protected String getToken() {
+        return get(KEY_TOKEN);
+    }
+
+    /**
+     * Gets the authorization after {@link #authorize(Account)} was invoked.
+     */
+    protected String getAuthorization() {
+        assertIsAuthorized();
+        return authorization;
+    }
+
+    /**
+     * Computes the authorization string.
+     * <p>
+     * The default is {@code token + '.' + base64url(jwkThumbprint)}. Subclasses may
+     * override this method if a different algorithm is used.
+     *
+     * @param account
+     *            {@link Account} to authorize with
+     * @return Authorization string
+     */
+    protected String computeAuthorization(Account account) {
+        return getToken()
+            + '.'
+            + Base64Url.encode(jwkThumbprint(account.getKeyPair().getPublic()));
+    }
+
+}

acme4j-client/src/main/java/org/shredzone/acme4j/challenge/HttpChallenge.java

@@ -13,44 +13,26 @@
  */
 package org.shredzone.acme4j.challenge;
 
-import org.jose4j.base64url.Base64Url;
-import org.shredzone.acme4j.Account;
-import org.shredzone.acme4j.util.ClaimBuilder;
 
 /**
  * Implements the {@code http-01} challenge.
  *
  * @author Richard "Shred" Körber
  */
-public class HttpChallenge extends GenericChallenge {
+public class HttpChallenge extends GenericTokenChallenge {
     private static final long serialVersionUID = 3322211185872544605L;
 
     /**
      * Challenge type name: {@value}
      */
     public static final String TYPE = "http-01";
 
-    private String authorization = null;
-
-    /**
-     * Authorizes the {@link Challenge} by signing it with an {@link Account}.
-     *
-     * @param account
-     *            {@link Account} to sign the challenge with
-     */
-    public void authorize(Account account) {
-        if (account == null) {
-            throw new NullPointerException("account must not be null");
-        }
-
-        authorization = getToken() + '.' + Base64Url.encode(jwkThumbprint(account.getKeyPair().getPublic()));
-    }
-
     /**
      * Returns the token to be used for this challenge.
      */
+    @Override
     public String getToken() {
-        return get(KEY_TOKEN);
+        return super.getToken();
     }
 
     /**
@@ -60,22 +42,9 @@ public String getToken() {
      * or ASCII encoded). There must not be any other leading or trailing characters
      * (like white-spaces or line breaks). Otherwise the challenge will fail.
      */
-    public String getAuthorization() {
-        if (authorization == null) {
-            throw new IllegalStateException("Challenge is not authorized yet");
-        }
-        return authorization;
-    }
-
     @Override
-    public void respond(ClaimBuilder cb) {
-        if (authorization == null) {
-            throw new IllegalStateException("Challenge is not authorized yet");
-        }
-
-        super.respond(cb);
-        cb.put(KEY_TOKEN, getToken());
-        cb.put(KEY_KEY_AUTHORIZATION, getAuthorization());
+    public String getAuthorization() {
+        return super.getAuthorization();
     }
 
     @Override

acme4j-client/src/main/java/org/shredzone/acme4j/challenge/ProofOfPossessionChallenge.java

@@ -40,6 +40,9 @@
 public class ProofOfPossessionChallenge extends GenericChallenge {
     private static final long serialVersionUID = 6212440828380185335L;
 
+    protected static final String KEY_CERTS = "certs";
+    protected static final String KEY_AUTHORIZATION = "authorization";
+
     /**
      * Challenge type name: {@value}
      */
@@ -96,7 +99,7 @@ public void importValidation(String validation) {
     public void unmarshall(Map<String, Object> map) {
         super.unmarshall(map);
 
-        List<String> certData = get("certs");
+        List<String> certData = get(KEY_CERTS);
         if (certData != null) {
             try {
                 CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
@@ -123,7 +126,7 @@ public void respond(ClaimBuilder cb) {
         super.respond(cb);
 
         try {
-            cb.put("authorization", JsonUtil.parseJson(validation));
+            cb.put(KEY_AUTHORIZATION, JsonUtil.parseJson(validation));
         } catch (JoseException ex) {
             // should not happen, as the JSON is prevalidated in the setter
             throw new IllegalStateException("validation: invalid JSON", ex);

acme4j-client/src/main/java/org/shredzone/acme4j/challenge/TlsSniChallenge.java

@@ -17,16 +17,14 @@
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 
-import org.jose4j.base64url.Base64Url;
 import org.shredzone.acme4j.Account;
-import org.shredzone.acme4j.util.ClaimBuilder;
 
 /**
  * Implements the {@code tls-sni-01} challenge.
  *
  * @author Richard "Shred" Körber
  */
-public class TlsSniChallenge extends GenericChallenge {
+public class TlsSniChallenge extends GenericTokenChallenge {
     private static final long serialVersionUID = 7370329525205430573L;
     private static final char[] HEX = "0123456789abcdef".toCharArray();
 
@@ -35,42 +33,21 @@ public class TlsSniChallenge extends GenericChallenge {
      */
     public static final String TYPE = "tls-sni-01";
 
-    private String authorization = null;
-    private String subject = null;
-
-    /**
-     * Authorizes the {@link Challenge} by signing it with an {@link Account}.
-     *
-     * @param account
-     *            {@link Account} to sign the challenge with
-     */
-    public void authorize(Account account) {
-        if (account == null) {
-            throw new NullPointerException("account must not be null");
-        }
-
-        authorization = getToken() + '.' + Base64Url.encode(jwkThumbprint(account.getKeyPair().getPublic()));
-
-        String hash = computeHash(authorization);
-        subject = hash.substring(0, 32) + '.' + hash.substring(32) + ".acme.invalid";
-    }
+    private String subject;
 
     /**
      * Return the subject to generate a self-signed certificate for.
      */
     public String getSubject() {
-        if (authorization == null) {
-            throw new IllegalStateException("Challenge is not authorized yet");
-        }
+        assertIsAuthorized();
         return subject;
     }
 
-
     @Override
-    public void respond(ClaimBuilder cb) {
-        super.respond(cb);
-        cb.put(KEY_TOKEN, getToken());
-        cb.put(KEY_KEY_AUTHORIZATION, getAuthorization());
+    public void authorize(Account account) {
+        super.authorize(account);
+        String hash = computeHash(getAuthorization());
+        subject = hash.substring(0, 32) + '.' + hash.substring(32) + ".acme.invalid";
     }
 
     @Override
@@ -103,16 +80,4 @@ private String computeHash(String z) {
         }
     }
 
-    private String getToken() {
-        return get(KEY_TOKEN);
-    }
-
-    private String getAuthorization() {
-        if (authorization == null) {
-            throw new IllegalStateException("Challenge is not authorized yet");
-        }
-
-        return authorization;
-    }
-
 }