Evaluate rate-limit relation when rate limit is exceeded

acme4j-client/src/main/java/org/shredzone/acme4j/connector/Connection.java

@@ -16,6 +16,7 @@ package org.shredzone.acme4j.connector;
 import java.io.IOException;
 import java.net.URI;
 import java.security.cert.X509Certificate;
+import java.util.Collection;
 import java.util.Date;
 import java.util.Map;
 
@@ -85,7 +86,8 @@ public interface Connection extends AutoCloseable {
     /**
      * Gets a relation link from the header.
      * <p>
-     * Relative links are resolved against the last request's URL.
+     * Relative links are resolved against the last request's URL. If there is more than
+     * one relation, the first one is returned.
      *
      * @param relation
      *            Link relation
@@ -93,6 +95,17 @@ public interface Connection extends AutoCloseable {
      */
     URI getLink(String relation);
 
+    /**
+     * Gets one or more relation link from the header.
+     * <p>
+     * Relative links are resolved against the last request's URL.
+     *
+     * @param relation
+     *            Link relation
+     * @return Collection of links, or {@code null} if there was no such relation link
+     */
+    Collection<URI> getLinks(String relation);
+
     /**
      * Returns the moment returned in a "Retry-After" header.
      *

acme4j-client/src/main/java/org/shredzone/acme4j/connector/DefaultConnection.java

@@ -27,6 +27,8 @@ import java.security.KeyPair;
 import java.security.cert.CertificateException;
 import java.security.cert.CertificateFactory;
 import java.security.cert.X509Certificate;
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Date;
 import java.util.List;
 import java.util.Map;
@@ -252,8 +254,24 @@ public class DefaultConnection implements Connection {
 
     @Override
     public URI getLink(String relation) {
+        Collection<URI> links = getLinks(relation);
+        if (links == null) {
+            return null;
+        }
+
+        if (links.size() > 1) {
+            LOG.debug("Link: {} - using the first of {}", relation, links.size());
+        }
+
+        return links.iterator().next();
+    }
+
+    @Override
+    public Collection<URI> getLinks(String relation) {
         assertConnectionIsOpen();
 
+        List<URI> result = new ArrayList<>();
+
         List<String> links = conn.getHeaderFields().get("Link");
         if (links != null) {
             Pattern p = Pattern.compile("<(.*?)>\\s*;\\s*rel=\"?"+ Pattern.quote(relation) + "\"?");
@@ -262,12 +280,12 @@ public class DefaultConnection implements Connection {
                 if (m.matches()) {
                     String location = m.group(1);
                     LOG.debug("Link: {} -> {}", relation, location);
-                    return resolveRelative(location);
+                    result.add(resolveRelative(location));
                 }
             }
         }
 
-        return null;
+        return (!result.isEmpty() ? result : null);
     }
 
     @Override
@@ -324,7 +342,8 @@ public class DefaultConnection implements Connection {
 
                 case ACME_ERROR_PREFIX + "rateLimited":
                 case ACME_ERROR_PREFIX_DEPRECATED + "rateLimited":
-                    throw new AcmeRateLimitExceededException(type, detail, getRetryAfterHeader());
+                    throw new AcmeRateLimitExceededException(
+                                type, detail, getRetryAfterHeader(), getLinks("rate-limit"));
 
                 default:
                     throw new AcmeServerException(type, detail);

acme4j-client/src/main/java/org/shredzone/acme4j/exception/AcmeRateLimitExceededException.java

@@ -13,6 +13,9 @@
  */
 package org.shredzone.acme4j.exception;
 
+import java.net.URI;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.Date;
 
 /**
@@ -22,6 +25,7 @@ public class AcmeRateLimitExceededException extends AcmeServerException {
     private static final long serialVersionUID = 4150484059796413069L;
 
     private final Date retryAfter;
+    private final Collection<URI> documents;
 
     /**
      * Creates a new {@link AcmeRateLimitExceededException}.
@@ -34,10 +38,13 @@ public class AcmeRateLimitExceededException extends AcmeServerException {
      * @param retryAfter
      *            The moment the request is expected to succeed again, may be {@code null}
      *            if not known
+     * @param documents
+     *            URIs pointing to documents about the rate limit that was hit
      */
-    public AcmeRateLimitExceededException(String type, String detail, Date retryAfter) {
+    public AcmeRateLimitExceededException(String type, String detail, Date retryAfter, Collection<URI> documents) {
         super(type, detail);
         this.retryAfter = retryAfter;
+        this.documents = (documents != null ? Collections.unmodifiableCollection(documents) : null);
     }
 
     /**
@@ -48,4 +55,12 @@ public class AcmeRateLimitExceededException extends AcmeServerException {
         return (retryAfter != null ? new Date(retryAfter.getTime()) : null);
     }
 
+    /**
+     * Collection of URIs pointing to documents about the rate limit that was hit.
+     * {@code null} if the server did not provide such URIs.
+     */
+    public Collection<URI> getDocuments() {
+        return documents;
+    }
+
 }

acme4j-client/src/test/java/org/shredzone/acme4j/connector/DefaultConnectionTest.java

@@ -189,6 +189,30 @@ public class DefaultConnectionTest {
         }
     }
 
+    /**
+     * Test that multiple link headers are evaluated.
+     */
+    @Test
+    public void testGetMultiLink() {
+        Map<String, List<String>> headers = new HashMap<>();
+        headers.put("Link", Arrays.asList(
+                        "<https://example.com/acme/terms1>; rel=\"terms-of-service\"",
+                        "<https://example.com/acme/terms2>; rel=\"terms-of-service\"",
+                        "<https://example.com/acme/terms3>; rel=\"terms-of-service\""
+                    ));
+
+        when(mockUrlConnection.getHeaderFields()).thenReturn(headers);
+
+        try (DefaultConnection conn = new DefaultConnection(mockHttpConnection)) {
+            conn.conn = mockUrlConnection;
+            assertThat(conn.getLinks("terms-of-service"), containsInAnyOrder(
+                        URI.create("https://example.com/acme/terms1"),
+                        URI.create("https://example.com/acme/terms2"),
+                        URI.create("https://example.com/acme/terms3")
+            ));
+        }
+    }
+
     /**
      * Test that no Location header returns {@code null}.
      */

acme4j-client/src/test/java/org/shredzone/acme4j/connector/DummyConnection.java

@@ -15,6 +15,7 @@ package org.shredzone.acme4j.connector;
 
 import java.net.URI;
 import java.security.cert.X509Certificate;
+import java.util.Collection;
 import java.util.Date;
 import java.util.Map;
 
@@ -63,6 +64,11 @@ public class DummyConnection implements Connection {
         throw new UnsupportedOperationException();
     }
 
+    @Override
+    public Collection<URI> getLinks(String relation) {
+        throw new UnsupportedOperationException();
+    }
+
     @Override
     public Date getRetryAfterHeader() {
         throw new UnsupportedOperationException();