Refactor OpenAI integration and enhance ChatService

Removed the old OpenAIService and integrated a new version with additional DTOs and a RestTemplate configuration. The `ChatServiceImpl` now makes use of the OpenAI API for generating responses. Jackson Kotlin module support added for JSON deserialization.

.run/MainApplication.run.xml

@@ -2,7 +2,6 @@
   <configuration default="false" name="MainApplication" type="SpringBootApplicationConfigurationType" factoryName="Spring Boot" nameIsGenerated="true">
     <envs>
       <env name="CLIENT_SECRET" value="notARealSecret" />
-      <env name="OPENAI_API_TOKEN" value="notARealSecret" />
     </envs>
     <module name="routing.server.main" />
     <option name="SPRING_BOOT_MAIN_CLASS" value="de.hbt.routing.MainApplication" />

module-server/server.gradle.kts

@@ -13,4 +13,5 @@ dependencies {
     kapt(libs.mapstruct.processor)
 
     implementation(libs.bundles.spring.boot.security)
+    implementation ("com.fasterxml.jackson.module:jackson-module-kotlin:2.17.+")
 }

module-server/src/main/kotlin/de/hbt/routing/configuration/OpenAIRestTemplateConfig.kt

@@ -0,0 +1,36 @@
+package de.hbt.routing.configuration
+
+import com.fasterxml.jackson.databind.DeserializationFeature
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.module.kotlin.registerKotlinModule
+import org.springframework.beans.factory.annotation.Qualifier
+import org.springframework.beans.factory.annotation.Value
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+import org.springframework.http.HttpRequest
+import org.springframework.http.client.ClientHttpRequestExecution
+import org.springframework.http.client.ClientHttpRequestInterceptor
+import org.springframework.web.client.RestTemplate
+
+@Configuration
+open class OpenAIRestTemplateConfig(@Value("\${openai.api.token}") private val apiKey: String) {
+
+    @Bean
+    @Qualifier("openaiRestTemplate")
+    open fun openaiRestTemplate(): RestTemplate {
+        val restTemplate = RestTemplate()
+        restTemplate.interceptors.add(ClientHttpRequestInterceptor { request: HttpRequest, body: ByteArray?, execution: ClientHttpRequestExecution ->
+            request.headers.add("Authorization", "Bearer $apiKey")
+            execution.execute(request, body!!)
+        })
+        return restTemplate
+    }
+
+    @Bean
+    open fun jacksonObjectMapper(): ObjectMapper {
+        return ObjectMapper().apply {
+            configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
+            registerKotlinModule()
+        }
+    }
+}

module-server/src/main/kotlin/de/hbt/routing/openai/OpenAIService.kt

@@ -0,0 +1,31 @@
+package de.hbt.routing.openai
+
+import de.hbt.routing.openai.dto.ChatRequest
+import de.hbt.routing.openai.dto.ChatResponse
+import mu.KotlinLogging
+import org.springframework.beans.factory.annotation.Qualifier
+import org.springframework.stereotype.Service
+import org.springframework.web.client.RestTemplate
+
+@Service
+class OpenAIService(@Qualifier("openaiRestTemplate") private val restTemplate: RestTemplate) {
+
+    fun chat(prompt: String): String {
+        // create a request
+        val request = ChatRequest("gpt-3.5-turbo", prompt)
+
+        // call the API
+        val response = restTemplate.postForObject("https://api.openai.com/v1/chat/completions", request, ChatResponse::class.java)
+
+        if (response?.choices == null || response.choices.isEmpty()) {
+            return "No response"
+        }
+
+        // return the first response
+        return response.choices.first().message.content
+    }
+
+    companion object {
+        private val log = KotlinLogging.logger {}
+    }
+}

module-server/src/main/kotlin/de/hbt/routing/openai/dto/ChatRequest.kt

@@ -0,0 +1,7 @@
+package de.hbt.routing.openai.dto
+
+data class ChatRequest(val model: String, val n: Int, val temperature: Double, val messages: MutableList<Message?>) {
+    constructor(model: String, prompt: String) : this(model, 1, 0.0, ArrayList<Message?>()) {
+        messages.add(Message("user", prompt))
+    }
+}

module-server/src/main/kotlin/de/hbt/routing/openai/dto/ChatResponse.kt

@@ -0,0 +1,6 @@
+package de.hbt.routing.openai.dto
+
+import lombok.Builder
+import lombok.extern.jackson.Jacksonized
+
+data class ChatResponse(val choices: List<Choice>)

module-server/src/main/kotlin/de/hbt/routing/openai/dto/Choice.kt

@@ -0,0 +1,6 @@
+package de.hbt.routing.openai.dto
+
+import lombok.Builder
+import lombok.extern.jackson.Jacksonized
+
+data class Choice(val index: Int, val message: Message)

module-server/src/main/kotlin/de/hbt/routing/openai/dto/Message.kt

@@ -0,0 +1,6 @@
+package de.hbt.routing.openai.dto
+
+import lombok.Builder
+import lombok.extern.jackson.Jacksonized
+
+data class Message(val role: String, val content: String)

module-server/src/main/kotlin/de/hbt/routing/service/ChatServiceImpl.kt

@@ -1,18 +1,19 @@
 package de.hbt.routing.service
 
+import de.hbt.routing.openai.OpenAIService
 import de.hbt.routing.service.helper.ConversationCache
 import org.springframework.stereotype.Service
 import java.util.*
 
 @Service
-class ChatServiceImpl(private val conversationCache: ConversationCache) : ChatService {
+class ChatServiceImpl(private val conversationCache: ConversationCache, private val openAIService: OpenAIService) : ChatService {
 
     override fun processPrompt(requestId: String, prompt: String): ChatService.Response {
         val uuid = requestId.ifBlank { UUID.randomUUID().toString() }
-        val mockResponse = "This is a mock response for prompt: $prompt"
-        val response = ChatService.Response(uuid, mockResponse)
+        val openAIResponse = openAIService.chat(prompt)
+        val response = ChatService.Response(uuid, openAIResponse)
 
-        conversationCache.addToConversation(uuid, ConversationCache.PromptAndAnswer(prompt, mockResponse))
+        conversationCache.addToConversation(uuid, ConversationCache.PromptAndAnswer(prompt, openAIResponse))
 
         return response
     }

module-server/src/main/kotlin/de/hbt/routing/service/OpenAIService.kt

@@ -1,17 +0,0 @@
-package de.hbt.routing.service
-
-import de.hbt.routing.property.ServiceProperties
-import mu.KotlinLogging
-import org.springframework.stereotype.Service
-
-@Service
-class OpenAIService(private val serviceProperties: ServiceProperties) {
-
-    fun call() {
-        log.info("Hallo, ich rufe bei OpenAI an")
-    }
-
-    companion object {
-        private val log = KotlinLogging.logger {}
-    }
-}