feat: support alternative cloudEvents prefix

Signed-off-by: Michele <lars.michele@tu-dortmund.de>
cloudevents · lyca · Feb 10, 2024 · Feb 10, 2024 · Feb 10, 2024 · Mar 8, 2024
commit c1e0fbd4659473d0c78e76f3f1b5dbe28738a164
diff --git a/spring/src/main/java/io/cloudevents/spring/amqp/CloudEventMessageConverter.java b/spring/src/main/java/io/cloudevents/spring/amqp/CloudEventMessageConverter.java
@@ -29,7 +29,7 @@
 
 /**
  * A {@link MessageConverter} that can translate to and from a {@link Message} and a {@link CloudEvent}.
- * The {@link CloudEventContext} is canonicalized, with key names given a {@code ce-} prefix in the
+ * The {@link CloudEventContext} is canonicalized, with key names given a {@code cloudEvents_} prefix in the
  * {@link MessageProperties}.
  *
  * @author Lars Michele
@@ -62,6 +62,9 @@ private MessageReader createMessageReader(Message message) {
 
     private String version(MessageProperties properties) {
         Object header = properties.getHeader(CloudEventsHeaders.SPEC_VERSION);
+        if (header == null) {
+            header = properties.getHeader(CloudEventsHeaders.ALT_SPEC_VERSION);
+        }
         return header == null ? null : header.toString();
     }
 
@@ -77,6 +80,9 @@ private String contentType(MessageProperties properties) {
         String contentType = properties.getContentType();
         if (contentType == null) {
             Object header = properties.getHeader(CloudEventsHeaders.CONTENT_TYPE);
+            if (header == null) {
+                header = properties.getHeader(CloudEventsHeaders.ALT_CONTENT_TYPE);
+            }
             return header == null ? null : header.toString();
         }
         return contentType;

diff --git a/spring/src/main/java/io/cloudevents/spring/amqp/CloudEventsHeaders.java b/spring/src/main/java/io/cloudevents/spring/amqp/CloudEventsHeaders.java
@@ -16,16 +16,40 @@
 
 package io.cloudevents.spring.amqp;
 
+/**
+ * Constants used throughout the Spring AMQP binding for cloud events.
+ */
 public class CloudEventsHeaders {
 
     /**
      * CloudEvent attributes MUST be prefixed with either "cloudEvents_" or "cloudEvents:" for use in the application-properties section.
+     *
      * @see <a href="https://github.com/cloudevents/spec/blob/main/cloudevents/bindings/amqp-protocol-binding.md#3131-amqp-application-property-names">
      * AMQP Protocol Binding for CloudEvents</a>
-     * */
+     */
     public static final String CE_PREFIX = "cloudEvents_";
-
+    /**
+     * CloudEvents AMQP consumers SHOULD understand the "cloudEvents" prefix with both the '_' and the ':' separators as permitted within the constraints of the client model.
+     *
+     * @see <a href="https://github.com/cloudevents/spec/blob/main/cloudevents/bindings/amqp-protocol-binding.md#3131-amqp-application-property-names">
+     * AMQP Protocol Binding for CloudEvents</a>
+     */
+    public static final String ALT_CE_PREFIX = "cloudEvents:";
+    /**
+     * The spec version header name.
+     */
     public static final String SPEC_VERSION = CE_PREFIX + "specversion";
-
+    /**
+     * The alternative spec version header name.
+     */
+    public static final String ALT_SPEC_VERSION = ALT_CE_PREFIX + "specversion";
+    /**
+     * The data content-type header name.
+     */
     public static final String CONTENT_TYPE = CE_PREFIX + "datacontenttype";
+
+    /**
+     * The alternative data content-type header name.
+     */
+    public static final String ALT_CONTENT_TYPE = ALT_CE_PREFIX + "datacontenttype";
 }
diff --git a/spring/src/main/java/io/cloudevents/spring/amqp/MessageBinaryMessageReader.java b/spring/src/main/java/io/cloudevents/spring/amqp/MessageBinaryMessageReader.java
@@ -49,7 +49,8 @@ protected boolean isContentTypeHeader(String key) {
 
     @Override
     protected boolean isCloudEventsHeader(String key) {
-        return key != null && key.length() > CE_PREFIX.length() && StringUtils.startsWithIgnoreCase(key, CE_PREFIX);
+        return key != null && key.length() > CE_PREFIX.length() && (StringUtils.startsWithIgnoreCase(key, CE_PREFIX)
+            || StringUtils.startsWithIgnoreCase(key, ALT_CE_PREFIX));
     }
 
     @Override