Enable base URL to be configurable for OpenAI using SPRING_AI_OPENAI_BASE_URL

spring-ai-spring-boot-autoconfigure/pom.xml

@@ -47,6 +47,12 @@
 			<optional>true</optional>
 		</dependency>
 
+		<dependency>
+			<groupId>com.squareup.retrofit2</groupId>
+			<artifactId>converter-jackson</artifactId>
+			<version>2.9.0</version>
+		</dependency>
+
 		<!-- test dependencies -->
 		<dependency>
 			<groupId>org.springframework.boot</groupId>

spring-ai-spring-boot-autoconfigure/src/main/java/org/springframework/ai/autoconfigure/openai/OpenAiAutoConfiguration.java

@@ -16,8 +16,15 @@
 
 package org.springframework.ai.autoconfigure.openai;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.theokanning.openai.OpenAiApi;
 import com.theokanning.openai.service.OpenAiService;
 
+import okhttp3.OkHttpClient;
+import retrofit2.Retrofit;
+import retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory;
+import retrofit2.converter.jackson.JacksonConverterFactory;
+
 import org.springframework.ai.autoconfigure.NativeHints;
 import org.springframework.ai.embedding.EmbeddingClient;
 import org.springframework.ai.openai.embedding.OpenAiEmbeddingClient;
@@ -45,11 +52,27 @@ public class OpenAiAutoConfiguration {
 
 	@Bean
 	public OpenAiService theoOpenAiService(OpenAiProperties openAiProperties) {
-		if (!StringUtils.hasText(openAiProperties.getApiKey())) {
-			throw new IllegalArgumentException(
-					"You must provide an API key with the property name " + CONFIG_PREFIX + ".api-key");
+		if (openAiProperties.getBaseUrl().equals("https://api.openai.com")) {
+			if (!StringUtils.hasText(openAiProperties.getApiKey())) {
+				throw new IllegalArgumentException(
+						"You must provide an API key with the property name " + CONFIG_PREFIX + ".api-key");
+			}
 		}
-		return new OpenAiService(openAiProperties.getApiKey(), openAiProperties.getDuration());
+
+		ObjectMapper mapper = OpenAiService.defaultObjectMapper();
+		OkHttpClient client = OpenAiService.defaultClient(openAiProperties.getApiKey(), openAiProperties.getDuration());
+
+		// Waiting for https://github.com/TheoKanning/openai-java/issues/249 to be
+		// resolved.
+		Retrofit retrofit = new Retrofit.Builder().baseUrl(openAiProperties.getBaseUrl())
+			.client(client)
+			.addConverterFactory(JacksonConverterFactory.create(mapper))
+			.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
+			.build();
+
+		OpenAiApi api = retrofit.create(OpenAiApi.class);
+
+		return new OpenAiService(api);
 	}
 
 	@Bean

spring-ai-spring-boot-autoconfigure/src/main/java/org/springframework/ai/autoconfigure/openai/OpenAiProperties.java

@@ -35,6 +35,8 @@ public class OpenAiProperties {
 
 	private String model = "gpt-3.5-turbo";
 
+	private String baseUrl = "https://api.openai.com";
+
 	public String getApiKey() {
 		return apiKey;
 	}
@@ -67,4 +69,12 @@ public class OpenAiProperties {
 		this.duration = duration;
 	}
 
+	public String getBaseUrl() {
+		return baseUrl;
+	}
+
+	public void setBaseUrl(String baseUrl) {
+		this.baseUrl = baseUrl;
+	}
+
 }