discord-rest: Add minimal error handling

Missing the response deserialization.

discord-rest/src/main/java/de/hhhammer/dchat/discord/rest/DiscordRest.java

@@ -1,14 +1,19 @@
 package de.hhhammer.dchat.discord.rest;
 
+import org.json.JSONException;
 import org.json.JSONObject;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
 import java.net.URI;
 import java.net.http.HttpClient;
 import java.net.http.HttpRequest;
 import java.net.http.HttpResponse;
+import java.util.Optional;
 
 public class DiscordRest {
+    private static final Logger logger = LoggerFactory.getLogger(DiscordRest.class);
     private static final String USER_AGENT = "DiscordBot (https://git.hhhammer.de/hamburghammer/dchat, main)";
     private static final String DISCORD_URL = "https://discord.com/api/v10";
     private final HttpClient httpClient;
@@ -30,11 +35,11 @@ public class DiscordRest {
 
         HttpResponse<Void> response = httpClient.send(request, HttpResponse.BodyHandlers.discarding());
         if (response.statusCode() != 201) {
-            // TODO: What about errors?
+            logger.error("Unexpected status code: {}", response.statusCode());
         }
     }
 
-    public String getMessage(int channelId, int messageId) throws IOException, InterruptedException {
+    public Optional<String> getMessage(int channelId, int messageId) throws IOException, InterruptedException {
         var uri = URI.create(DISCORD_URL + "/channels/%s/messages/%s".formatted(channelId, messageId));
         HttpRequest request = HttpRequest.newBuilder()
                 .uri(uri)
@@ -45,9 +50,14 @@ public class DiscordRest {
 
         HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
         if (response.statusCode() != 200) {
-            return ""; // TODO: Think about transparently inform caller about error.
+            logger.error("Could not get message");
+            return Optional.empty();
+        }
+        try {
+            final var responseJson = new JSONObject(response.body());
+            return Optional.of(responseJson.getString("content")); // content not be set -> https://discord.com/developers/docs/resources/message#message-object-message-structure
+        } catch (JSONException e) {
+            return Optional.empty();
         }
-        final var responseJson = new JSONObject(response.body());
-        return responseJson.getString("content"); // FIXME: Can throw exception if content is not set -> https://discord.com/developers/docs/resources/message#message-object-message-structure
     }
 }

openai-rest/pom.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>de.hhhammer.dchat</groupId>
+        <artifactId>dchat</artifactId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+
+    <groupId>de.hhhammer.dchat.openai.rest</groupId>
+    <artifactId>openai-rest</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.json</groupId>
+            <artifactId>json</artifactId>
+        </dependency>
+    </dependencies>
+</project>

openai-rest/src/main/java/de/hhhammer/dchat/openai/rest/ChatGPTRequestBuilder.java

@@ -0,0 +1,57 @@
+package de.hhhammer.dchat.openai.rest;
+
+import de.hhhammer.dchat.openai.rest.MessageContext.PreviousInteraction;
+import de.hhhammer.dchat.openai.rest.MessageContext.ReplyInteraction;
+import de.hhhammer.dchat.openai.rest.models.ChatGPTRequest;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public final class ChatGPTRequestBuilder {
+    private static final String contextModel = "gpt-4o-mini";
+
+    public ChatGPTRequestBuilder() {
+    }
+
+    @NotNull
+    private static List<ChatGPTRequest.Message> getMessages(final List<? extends MessageContext> contextMessages, final String message, final String systemMessage) {
+        final ChatGPTRequest.Message systemMsg = new ChatGPTRequest.Message("system", systemMessage);
+        final List<ChatGPTRequest.Message> contextMsgs = getContextMessages(contextMessages);
+        final ChatGPTRequest.Message userMessage = new ChatGPTRequest.Message("user", message);
+        final List<ChatGPTRequest.Message> messages = new ArrayList<>();
+        messages.add(systemMsg);
+        messages.addAll(contextMsgs);
+        messages.add(userMessage);
+        return messages;
+    }
+
+    @NotNull
+    private static List<ChatGPTRequest.Message> getContextMessages(final List<? extends MessageContext> contextMessages) {
+        return contextMessages.stream()
+                .map(ChatGPTRequestBuilder::mapContextMessages)
+                .flatMap(List::stream)
+                .toList();
+    }
+
+    @NotNull
+    private static List<ChatGPTRequest.Message> mapContextMessages(final MessageContext contextMessage) {
+        return switch (contextMessage) {
+            case PreviousInteraction previousInteractions -> List.of(
+                    new ChatGPTRequest.Message("user", previousInteractions.question()),
+                    new ChatGPTRequest.Message("assistant", previousInteractions.answer())
+            );
+            case ReplyInteraction replyInteractions ->
+                    List.of(new ChatGPTRequest.Message("assistant", replyInteractions.answer()));
+        };
+    }
+
+    public ChatGPTRequest contextRequest(final List<? extends MessageContext> contextMessages, final String message, final String systemMessage) {
+        final List<ChatGPTRequest.Message> messages = getMessages(contextMessages, message, systemMessage);
+        return new ChatGPTRequest(
+                contextModel,
+                messages,
+                0.7f
+        );
+    }
+}

openai-rest/src/main/java/de/hhhammer/dchat/openai/rest/ChatGPTService.java

@@ -0,0 +1,40 @@
+package de.hhhammer.dchat.openai.rest;
+
+import de.hhhammer.dchat.openai.rest.models.ChatGPTRequest;
+import de.hhhammer.dchat.openai.rest.models.ChatGPTResponse;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+
+public final class ChatGPTService {
+    private final String apiKey;
+    private final HttpClient httpClient;
+
+    public ChatGPTService(final String apiKey, final HttpClient httpClient) {
+        this.apiKey = apiKey;
+        this.httpClient = httpClient;
+    }
+
+    public ChatGPTResponse submit(final ChatGPTRequest chatGPTRequest) throws IOException, InterruptedException, ResponseException {
+        final String data = chatGPTRequest.toJson().toString();
+        final URI uri = URI.create("https://api.openai.com/v1/chat/completions");
+        final HttpRequest request = HttpRequest.newBuilder(uri)
+                .POST(HttpRequest.BodyPublishers.ofString(data))
+                .setHeader("Content-Type", "application/json")
+                .setHeader("Authorization", "Bearer " + this.apiKey)
+                .timeout(Duration.ofMinutes(5))
+                .build();
+
+        final HttpResponse<InputStream> responseStream = httpClient.send(request, HttpResponse.BodyHandlers.ofInputStream());
+        if (responseStream.statusCode() != 200) {
+            throw new ResponseException("Response status code was not 200: " + responseStream.statusCode());
+        }
+
+        return mapper.readValue(responseStream.body(), ChatGPTResponse.class);
+    }
+}

openai-rest/src/main/java/de/hhhammer/dchat/openai/rest/JsonSerializable.java

@@ -0,0 +1,9 @@
+package de.hhhammer.dchat.openai.rest;
+
+import org.jetbrains.annotations.NotNull;
+import org.json.JSONObject;
+
+public interface JsonSerializable {
+    @NotNull
+    JSONObject toJson();
+}

openai-rest/src/main/java/de/hhhammer/dchat/openai/rest/MessageContext.java

@@ -0,0 +1,9 @@
+package de.hhhammer.dchat.openai.rest;
+
+public sealed interface MessageContext {
+    record ReplyInteraction(String answer) implements MessageContext {
+    }
+
+    record PreviousInteraction(String question, String answer) implements MessageContext {
+    }
+}

openai-rest/src/main/java/de/hhhammer/dchat/openai/rest/ResponseException.java

@@ -0,0 +1,7 @@
+package de.hhhammer.dchat.openai.rest;
+
+public final class ResponseException extends Exception {
+    public ResponseException(final String message) {
+        super(message);
+    }
+}

openai-rest/src/main/java/de/hhhammer/dchat/openai/rest/models/ChatGPTRequest.java

@@ -0,0 +1,31 @@
+package de.hhhammer.dchat.openai.rest.models;
+
+import de.hhhammer.dchat.openai.rest.JsonSerializable;
+import org.jetbrains.annotations.NotNull;
+import org.json.JSONArray;
+import org.json.JSONObject;
+
+import java.util.List;
+
+public record ChatGPTRequest(String model, List<Message> messages, float temperature) implements JsonSerializable {
+
+    @Override
+    public @NotNull JSONObject toJson() {
+        final var json = new JSONObject();
+        json.put("model", model);
+        final var messageJson = new JSONArray(messages.stream().map(Message::toJson).toList());
+        json.put("messages", messageJson);
+        json.put("temperature", temperature);
+        return json;
+    }
+
+    public record Message(String role, String content) implements JsonSerializable {
+        @Override
+        public @NotNull JSONObject toJson() {
+            final var json = new JSONObject();
+            json.put("role", role);
+            json.put("content", content);
+            return json;
+        }
+    }
+}

openai-rest/src/main/java/de/hhhammer/dchat/openai/rest/models/ChatGPTResponse.java

@@ -0,0 +1,49 @@
+package de.hhhammer.dchat.openai.rest.models;
+
+import de.hhhammer.dchat.openai.rest.JsonSerializable;
+import org.jetbrains.annotations.NotNull;
+import org.json.JSONArray;
+import org.json.JSONObject;
+
+import java.util.List;
+
+public record ChatGPTResponse(Usage usage, List<Choice> choices) implements JsonSerializable {
+    @Override
+    public @NotNull JSONObject toJson() {
+        final var json = new JSONObject();
+        json.put("usage", usage.toJson());
+        final var jsonChoices = new JSONArray(choices.stream().map(Choice::toJson).toList());
+        json.put("choices", jsonChoices);
+        return json;
+    }
+
+    public record Usage(int promptTokens, int completionTokens, int totalTokens) implements JsonSerializable {
+        @Override
+        public @NotNull JSONObject toJson() {
+            final var json = new JSONObject();
+            json.put("prompt_tokens", promptTokens);
+            json.put("completion_tokens", completionTokens);
+            json.put("total_tokens", totalTokens);
+            return json;
+        }
+    }
+
+    public record Choice(Message message) implements JsonSerializable {
+        @Override
+        public @NotNull JSONObject toJson() {
+            final var json = new JSONObject();
+            json.put("message", message.toJson());
+            return json;
+        }
+
+        public record Message(String role, String content) implements JsonSerializable {
+            @Override
+            public @NotNull JSONObject toJson() {
+                final var json = new JSONObject();
+                json.put("role", role);
+                json.put("content", content);
+                return json;
+            }
+        }
+    }
+}

openai-rest/src/main/java/module-info.java

@@ -0,0 +1,9 @@
+module de.hhhammer.dchat.openai.rest {
+    exports de.hhhammer.dchat.openai.rest;
+    exports de.hhhammer.dchat.openai.rest.models;
+
+    requires java.net.http;
+
+    requires org.json;
+    requires static org.jetbrains.annotations;
+}

pom.xml

@@ -98,5 +98,6 @@
         <module>bot</module>
         <module>discord-ws</module>
         <module>discord-rest</module>
+        <module>openai-rest</module>
     </modules>
-</project>
+</project>