GH-876: stream.content() swallowing blank space

* Fixing an issue where calling stream.content() method swallows leading
  blank spaces.

Resolves #1089
Resolves #1089

Author: sobychacko

models/spring-ai-openai/src/test/java/org/springframework/ai/openai/chat/OpenAiChatModelIT.java

@@ -107,6 +107,55 @@ void streamCompletenessTest() throws InterruptedException {
 		});
 	}
 
+	@Test
+	void streamCompletenessTestWithChatResponse() throws InterruptedException {
+		UserMessage userMessage = new UserMessage("Who is George Washington? - use first as 1st");
+		Prompt prompt = new Prompt(List.of(userMessage));
+
+		StringBuilder answer = new StringBuilder();
+		CountDownLatch latch = new CountDownLatch(1);
+
+		ChatClient chatClient = ChatClient.builder(openAiChatModel).build();
+
+		Flux<ChatResponse> chatResponseFlux = chatClient.prompt(prompt)
+			.stream()
+			.chatResponse()
+			.doOnNext(chatResponse -> {
+				String responseContent = chatResponse.getResults().get(0).getOutput().getContent();
+				answer.append(responseContent);
+			})
+			.doOnComplete(() -> {
+				logger.info(answer.toString());
+				latch.countDown();
+			});
+		chatResponseFlux.subscribe();
+		assertThat(latch.await(120, TimeUnit.SECONDS)).isTrue();
+		assertThat(answer).contains("the 1st ");
+	}
+
+	@Test
+	void ensureChatResponseAsContentDoesNotSwallowBlankSpace() throws InterruptedException {
+		UserMessage userMessage = new UserMessage("Who is George Washington? - use first as 1st");
+		Prompt prompt = new Prompt(List.of(userMessage));
+
+		StringBuilder answer = new StringBuilder();
+		CountDownLatch latch = new CountDownLatch(1);
+
+		ChatClient chatClient = ChatClient.builder(openAiChatModel).build();
+
+		Flux<String> chatResponseFlux = chatClient.prompt(prompt)
+			.stream()
+			.content()
+			.doOnNext(answer::append)
+			.doOnComplete(() -> {
+				logger.info(answer.toString());
+				latch.countDown();
+			});
+		chatResponseFlux.subscribe();
+		assertThat(latch.await(120, TimeUnit.SECONDS)).isTrue();
+		assertThat(answer).contains("the 1st ");
+	}
+
 	@Test
 	void streamRoleTest() {
 		UserMessage userMessage = new UserMessage(

models/spring-ai-openai/src/test/java/org/springframework/ai/openai/testutils/AbstractIT.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.ai.openai.testutils;
 
 import java.util.List;
@@ -31,6 +32,7 @@
 import org.springframework.ai.image.ImageModel;
 import org.springframework.ai.openai.OpenAiAudioSpeechModel;
 import org.springframework.ai.openai.OpenAiAudioTranscriptionModel;
+import org.springframework.ai.openai.OpenAiChatModel;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.core.io.Resource;
@@ -48,6 +50,9 @@ public abstract class AbstractIT {
 	@Autowired
 	protected StreamingChatModel streamingChatModel;
 
+	@Autowired
+	protected OpenAiChatModel openAiChatModel;
+
 	@Autowired
 	protected OpenAiAudioTranscriptionModel transcriptionModel;
 

spring-ai-core/src/main/java/org/springframework/ai/chat/client/ChatClient.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 - 2024 the original author or authors.
+ * Copyright 2023-2024 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.
@@ -162,7 +162,7 @@ interface StreamPromptResponseSpec {
 
 		Flux<ChatResponse> chatResponse();
 
-		public Flux<String> content();
+		Flux<String> content();
 
 	}
 

spring-ai-core/src/main/java/org/springframework/ai/chat/client/DefaultChatClient.java

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2023-2024 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.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package org.springframework.ai.chat.client;
 
 import java.io.IOException;
@@ -44,6 +60,7 @@
  * @author Christian Tzolov
  * @author Josh Long
  * @author Arjen Poutsma
+ * @author Soby Chacko
  * @since 1.0.0
  */
 public class DefaultChatClient implements ChatClient {
@@ -204,7 +221,7 @@ protected Map<String, Object> params() {
 
 	public static class DefaultAdvisorSpec implements AdvisorSpec {
 
-		private List<RequestResponseAdvisor> advisors = new ArrayList<>();
+		private final List<RequestResponseAdvisor> advisors = new ArrayList<>();
 
 		private final Map<String, Object> params = new HashMap<>();
 
@@ -446,7 +463,7 @@ public Flux<String> content() {
 					return "";
 				}
 				return r.getResult().getOutput().getContent();
-			}).filter(v -> StringUtils.hasLength(v));
+			}).filter(StringUtils::hasLength);
 		}
 
 	}
@@ -473,7 +490,7 @@ public static class DefaultChatClientRequestSpec implements ChatClientRequestSpe
 
 		private final Map<String, Object> systemParams = new HashMap<>();
 
-		private List<RequestResponseAdvisor> advisors = new ArrayList<>();
+		private final List<RequestResponseAdvisor> advisors = new ArrayList<>();
 
 		private final Map<String, Object> advisorParams = new HashMap<>();
 
@@ -804,7 +821,7 @@ public Flux<String> content() {
 					return "";
 				}
 				return r.getResult().getOutput().getContent();
-			}).filter(v -> StringUtils.hasText(v));
+			}).filter(StringUtils::hasLength);
 		}
 
 	}
@@ -825,7 +842,7 @@ public CallPromptResponseSpec call() {
 		}
 
 		public StreamPromptResponseSpec stream() {
-			return new DefaultStreamPromptResponseSpec((StreamingChatModel) this.chatModel, this.prompt);
+			return new DefaultStreamPromptResponseSpec(this.chatModel, this.prompt);
 		}
 
 	}