Enhance OpenAI Authentication and Configuration

- Add org-id and project-id properties with unified merging logic
- Update autoconfig and docs for all OpenAI models
- Introduce OpenAiChatOptions#httpHeaders option
- Add integration test for httpHeaders and update docs

Resolves #1141

Author: tzolov

models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiChatModel.java

@@ -15,7 +15,16 @@
  */
 package org.springframework.ai.openai;
 
-import io.micrometer.observation.ObservationRegistry;
+import java.util.ArrayList;
+import java.util.Base64;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Collectors;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.ai.chat.messages.AssistantMessage;
@@ -26,8 +35,16 @@
 import org.springframework.ai.chat.metadata.ChatResponseMetadata;
 import org.springframework.ai.chat.metadata.EmptyUsage;
 import org.springframework.ai.chat.metadata.RateLimit;
-import org.springframework.ai.chat.model.*;
-import org.springframework.ai.chat.observation.*;
+import org.springframework.ai.chat.model.AbstractToolCallSupport;
+import org.springframework.ai.chat.model.ChatModel;
+import org.springframework.ai.chat.model.ChatResponse;
+import org.springframework.ai.chat.model.Generation;
+import org.springframework.ai.chat.model.StreamingChatModel;
+import org.springframework.ai.chat.observation.ChatModelObservationContext;
+import org.springframework.ai.chat.observation.ChatModelObservationConvention;
+import org.springframework.ai.chat.observation.ChatModelObservationDocumentation;
+import org.springframework.ai.chat.observation.ChatModelRequestOptions;
+import org.springframework.ai.chat.observation.DefaultChatModelObservationConvention;
 import org.springframework.ai.chat.prompt.ChatOptions;
 import org.springframework.ai.chat.prompt.Prompt;
 import org.springframework.ai.model.ModelOptionsUtils;
@@ -52,13 +69,13 @@
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
 import org.springframework.util.MimeType;
+import org.springframework.util.MultiValueMap;
 import org.springframework.util.StringUtils;
+
+import io.micrometer.observation.ObservationRegistry;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
-import java.util.*;
-import java.util.concurrent.ConcurrentHashMap;
-
 /**
  * {@link ChatModel} and {@link StreamingChatModel} implementation for {@literal OpenAI}
  * backed by {@link OpenAiApi}.
@@ -204,7 +221,7 @@ public ChatResponse call(Prompt prompt) {
 			.observe(() -> {
 
 				ResponseEntity<ChatCompletion> completionEntity = this.retryTemplate
-					.execute(ctx -> this.openAiApi.chatCompletionEntity(request));
+					.execute(ctx -> this.openAiApi.chatCompletionEntity(request, getAdditionalHttpHeaders(prompt)));
 
 				var chatCompletion = completionEntity.getBody();
 
@@ -258,7 +275,7 @@ public Flux<ChatResponse> stream(Prompt prompt) {
 		ChatCompletionRequest request = createRequest(prompt, true);
 
 		Flux<OpenAiApi.ChatCompletionChunk> completionChunks = this.retryTemplate
-			.execute(ctx -> this.openAiApi.chatCompletionStream(request));
+			.execute(ctx -> this.openAiApi.chatCompletionStream(request, getAdditionalHttpHeaders(prompt)));
 
 		// For chunked responses, only the first chunk contains the choice role.
 		// The rest of the chunks with same ID share the same role.
@@ -315,6 +332,16 @@ public Flux<ChatResponse> stream(Prompt prompt) {
 		});
 	}
 
+	private MultiValueMap<String, String> getAdditionalHttpHeaders(Prompt prompt) {
+
+		Map<String, String> headers = new HashMap<>(this.defaultOptions.getHttpHeaders());
+		if (prompt.getOptions() != null && prompt.getOptions() instanceof OpenAiChatOptions chatOptions) {
+			headers.putAll(chatOptions.getHttpHeaders());
+		}
+		return CollectionUtils.toMultiValueMap(
+				headers.entrySet().stream().collect(Collectors.toMap(e -> e.getKey(), e -> List.of(e.getValue()))));
+	}
+
 	private Generation buildGeneration(Choice choice, Map<String, Object> metadata) {
 		List<AssistantMessage.ToolCall> toolCalls = choice.message().toolCalls() == null ? List.of()
 				: choice.message()

models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiChatOptions.java

@@ -16,6 +16,7 @@
 package org.springframework.ai.openai;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -169,6 +170,13 @@ public class OpenAiChatOptions implements FunctionCallingOptions, ChatOptions {
 	@NestedConfigurationProperty
 	@JsonIgnore
 	private Set<String> functions = new HashSet<>();
+
+	/**
+	 * Optional HTTP headers to be added to the chat completion request.
+	 */
+	@NestedConfigurationProperty
+	@JsonIgnore
+	private Map<String, String> httpHeaders = new HashMap<>();
 	// @formatter:on
 
 	public static Builder builder() {
@@ -299,6 +307,12 @@ public Builder withFunction(String functionName) {
 			return this;
 		}
 
+		public Builder withHttpHeaders(Map<String, String> httpHeaders) {
+			Assert.notNull(httpHeaders, "HTTP headers must not be null");
+			this.options.httpHeaders = httpHeaders;
+			return this;
+		}
+
 		public OpenAiChatOptions build() {
 			return this.options;
 		}
@@ -478,6 +492,14 @@ public void setFunctions(Set<String> functionNames) {
 		this.functions = functionNames;
 	}
 
+	public Map<String, String> getHttpHeaders() {
+		return this.httpHeaders;
+	}
+
+	public void setHttpHeaders(Map<String, String> httpHeaders) {
+		this.httpHeaders = httpHeaders;
+	}
+
 	@Override
 	public int hashCode() {
 		final int prime = 31;
@@ -662,6 +684,7 @@ public static OpenAiChatOptions fromOptions(OpenAiChatOptions fromOptions) {
 			.withParallelToolCalls(fromOptions.getParallelToolCalls())
 			.withFunctionCallbacks(fromOptions.getFunctionCallbacks())
 			.withFunctions(fromOptions.getFunctions())
+			.withHttpHeaders(fromOptions.getHttpHeaders())
 			.build();
 	}