Add protected encode method to WebFlux AbstractGraphQlHttpHandler

This helps to encode directly when needed, e.g. for multipart
stream with incremental delivery.

See gh-959

Author: rstoyanchev

spring-graphql/src/main/java/org/springframework/graphql/server/webflux/AbstractGraphQlHttpHandler.java

@@ -18,6 +18,7 @@
 
 
 import java.util.List;
+import java.util.Map;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -131,13 +132,24 @@ private static Mono<SerializableGraphQlRequest> applyApplicationGraphQlFallback(
 	protected abstract Mono<ServerResponse> prepareResponse(ServerRequest request, WebGraphQlResponse response);
 
 	/**
-	 * Encode the GraphQL response if custom codecs were provided, or otherwise
-	 * return the result map.
+	 * Encode the GraphQL response if custom codecs were provided, or return the result map.
 	 * @param response the GraphQL response
 	 * @return the encoded response or the result map
 	 */
 	protected Object encodeResponseIfNecessary(WebGraphQlResponse response) {
-		return (this.codecDelegate != null) ? this.codecDelegate.encode(response) : response.toMap();
+		Map<String, Object> resultMap = response.toMap();
+		return (this.codecDelegate != null) ? encode(resultMap) : resultMap;
+	}
+
+	/**
+	 * Encode the result map.
+	 * <p>This method assumes that a {@link CodecConfigurer} has been provided.
+	 * @param resultMap the result to encode
+	 * @return the encoded result map
+	 */
+	protected DataBuffer encode(Map<String, Object> resultMap) {
+		Assert.state(this.codecDelegate != null, "CodecConfigurer was not provided");
+		return this.codecDelegate.encode(resultMap);
 	}
 
 }

spring-graphql/src/main/java/org/springframework/graphql/server/webflux/HttpCodecDelegate.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,7 +26,6 @@
 import org.springframework.core.codec.Encoder;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DefaultDataBufferFactory;
-import org.springframework.graphql.GraphQlResponse;
 import org.springframework.graphql.server.support.SerializableGraphQlRequest;
 import org.springframework.http.MediaType;
 import org.springframework.http.codec.CodecConfigurer;
@@ -77,9 +76,9 @@ private static Encoder<?> findJsonEncoder(CodecConfigurer configurer) {
 
 
 	@SuppressWarnings("unchecked")
-	DataBuffer encode(GraphQlResponse response) {
-		return ((Encoder<Map<String, Object>>) this.encoder)
-				.encodeValue(response.toMap(), DefaultDataBufferFactory.sharedInstance, RESPONSE_TYPE, MimeTypeUtils.APPLICATION_JSON, null);
+	DataBuffer encode(Map<String, Object> resultMap) {
+		return ((Encoder<Map<String, Object>>) this.encoder).encodeValue(
+				resultMap, DefaultDataBufferFactory.sharedInstance, RESPONSE_TYPE, MimeTypeUtils.APPLICATION_JSON, null);
 	}
 
 	@SuppressWarnings("unchecked")