Merge pull request #23 from AgentSchmecker/feature/chat-request-model

Adds feature for /api/chat access via OllamaAPI

docs/docs/apis-ask/chat.md

@@ -0,0 +1,98 @@
+---
+sidebar_position: 7
+---
+
+# Chat
+
+This API lets you create a conversation with LLMs. Using this API enables you to ask questions to the model including 
+information using the history of already asked questions and the respective answers.
+
+## Create a new conversation and use chat history to augment follow up questions
+
+```java
+public class Main {
+
+    public static void main(String[] args) {
+
+        String host = "http://localhost:11434/";
+
+        OllamaAPI ollamaAPI = new OllamaAPI(host);
+        OllamaChatRequestBuilder builder = OllamaChatRequestBuilder.getInstance(OllamaModelType.LLAMA2);
+
+        // create first user question
+        OllamaChatRequestModel requestModel = builder.withMessage(OllamaChatMessageRole.USER,"What is the capital of France?")
+             .build();
+
+        // start conversation with model
+        OllamaChatResult chatResult = ollamaAPI.chat(requestModel);
+
+        System.out.println("First answer: " + chatResult.getResponse());
+
+        // create next userQuestion
+        requestModel = builder.withMessages(chatResult.getChatHistory()).withMessage(OllamaChatMessageRole.USER,"And what is the second largest city?").build();
+
+        // "continue" conversation with model
+        chatResult = ollamaAPI.chat(requestModel);
+
+        System.out.println("Second answer: " + chatResult.getResponse());
+
+        System.out.println("Chat History: " + chatResult.getChatHistory());
+    }
+}
+
+```
+You will get a response similar to:
+
+> First answer: Should be Paris!
+> 
+> Second answer: Marseille.
+> 
+> Chat History:
+
+```json
+[ {
+    "role" : "user",
+    "content" : "What is the capital of France?",
+    "images" : [ ]
+  }, {
+    "role" : "assistant",
+    "content" : "Should be Paris!",
+    "images" : [ ]
+  }, {
+    "role" : "user",
+    "content" : "And what is the second largest city?",
+    "images" : [ ]
+  }, {
+    "role" : "assistant",
+    "content" : "Marseille.",
+    "images" : [ ]
+  } ]
+```
+
+## Create a new conversation with individual system prompt
+```java
+public class Main {
+
+    public static void main(String[] args) {
+
+        String host = "http://localhost:11434/";
+
+        OllamaAPI ollamaAPI = new OllamaAPI(host);
+        OllamaChatRequestBuilder builder = OllamaChatRequestBuilder.getInstance(OllamaModelType.LLAMA2);
+
+        // create request with system-prompt (overriding the model defaults) and user question
+        OllamaChatRequestModel requestModel = builder.withMessage(OllamaChatMessageRole.SYSTEM, "You are a silent bot that only says 'NI'. Do not say anything else under any circumstances!")
+             .withMessage(OllamaChatMessageRole.USER,"What is the capital of France? And what's France's connection with Mona Lisa?")
+             .build();
+
+        // start conversation with model
+        OllamaChatResult chatResult = ollamaAPI.chat(requestModel);
+
+        System.out.println(chatResult.getResponse());
+    }
+}
+
+```
+You will get a response similar to:
+
+> NI.

src/main/java/io/github/amithkoujalgi/ollama4j/core/OllamaAPI.java

@@ -2,10 +2,16 @@ package io.github.amithkoujalgi.ollama4j.core;
 
 import io.github.amithkoujalgi.ollama4j.core.exceptions.OllamaBaseException;
 import io.github.amithkoujalgi.ollama4j.core.models.*;
+import io.github.amithkoujalgi.ollama4j.core.models.chat.OllamaChatMessage;
+import io.github.amithkoujalgi.ollama4j.core.models.chat.OllamaChatRequestModel;
+import io.github.amithkoujalgi.ollama4j.core.models.chat.OllamaChatResult;
+import io.github.amithkoujalgi.ollama4j.core.models.chat.OllamaChatRequestBuilder;
 import io.github.amithkoujalgi.ollama4j.core.models.request.CustomModelFileContentsRequest;
 import io.github.amithkoujalgi.ollama4j.core.models.request.CustomModelFilePathRequest;
 import io.github.amithkoujalgi.ollama4j.core.models.request.ModelEmbeddingsRequest;
 import io.github.amithkoujalgi.ollama4j.core.models.request.ModelRequest;
+import io.github.amithkoujalgi.ollama4j.core.models.request.OllamaChatEndpointCaller;
+import io.github.amithkoujalgi.ollama4j.core.models.request.OllamaGenerateEndpointCaller;
 import io.github.amithkoujalgi.ollama4j.core.utils.Options;
 import io.github.amithkoujalgi.ollama4j.core.utils.Utils;
 import java.io.BufferedReader;
@@ -343,7 +349,7 @@ public class OllamaAPI {
       throws OllamaBaseException, IOException, InterruptedException {
     OllamaRequestModel ollamaRequestModel = new OllamaRequestModel(model, prompt);
     ollamaRequestModel.setOptions(options.getOptionsMap());
-    return generateSync(ollamaRequestModel);
+    return generateSyncForOllamaRequestModel(ollamaRequestModel);
   }
 
   /**
@@ -387,7 +393,7 @@ public class OllamaAPI {
     }
     OllamaRequestModel ollamaRequestModel = new OllamaRequestModel(model, prompt, images);
     ollamaRequestModel.setOptions(options.getOptionsMap());
-    return generateSync(ollamaRequestModel);
+    return generateSyncForOllamaRequestModel(ollamaRequestModel);
   }
 
   /**
@@ -411,9 +417,50 @@ public class OllamaAPI {
     }
     OllamaRequestModel ollamaRequestModel = new OllamaRequestModel(model, prompt, images);
     ollamaRequestModel.setOptions(options.getOptionsMap());
-    return generateSync(ollamaRequestModel);
+    return generateSyncForOllamaRequestModel(ollamaRequestModel);
   }
 
+
+  
+  /**
+   * Ask a question to a model based on a given message stack (i.e. a chat history). Creates a synchronous call to the api 
+   * 'api/chat'. 
+   * 
+   * @param model the ollama model to ask the question to
+   * @param messages chat history / message stack to send to the model
+   * @return {@link OllamaChatResult} containing the api response and the message history including the newly aqcuired assistant response.
+     * @throws OllamaBaseException any response code than 200 has been returned
+     * @throws IOException in case the responseStream can not be read
+     * @throws InterruptedException in case the server is not reachable or network issues happen
+   */
+  public OllamaChatResult chat(String model, List<OllamaChatMessage> messages)  throws OllamaBaseException, IOException, InterruptedException{
+    OllamaChatRequestBuilder builder = OllamaChatRequestBuilder.getInstance(model);
+    return chat(builder.withMessages(messages).build());
+  }
+
+  /**
+   * Ask a question to a model using an {@link OllamaChatRequestModel}. This can be constructed using an {@link OllamaChatRequestBuilder}. 
+   * 
+   * Hint: the {@link OllamaChatRequestModel#getStream()} property is not implemented
+   * 
+   * @param request request object to be sent to the server
+   * @return 
+  * @throws OllamaBaseException any response code than 200 has been returned
+  * @throws IOException in case the responseStream can not be read
+  * @throws InterruptedException in case the server is not reachable or network issues happen
+   */
+  public OllamaChatResult chat(OllamaChatRequestModel request)  throws OllamaBaseException, IOException, InterruptedException{
+    OllamaChatEndpointCaller requestCaller = new OllamaChatEndpointCaller(host, basicAuth, requestTimeoutSeconds, verbose);
+    //TODO: implement async way
+    if(request.isStream()){
+      throw new UnsupportedOperationException("Streamed chat responses are not implemented yet");
+    }
+    OllamaResult result = requestCaller.generateSync(request);
+    return new OllamaChatResult(result.getResponse(), result.getResponseTime(), result.getHttpStatusCode(), request.getMessages());
+  }
+
+  // technical private methods //
+
   private static String encodeFileToBase64(File file) throws IOException {
     return Base64.getEncoder().encodeToString(Files.readAllBytes(file.toPath()));
   }
@@ -436,58 +483,10 @@ public class OllamaAPI {
     }
   }
 
-  private OllamaResult generateSync(OllamaRequestModel ollamaRequestModel)
+  private OllamaResult generateSyncForOllamaRequestModel(OllamaRequestModel ollamaRequestModel)
       throws OllamaBaseException, IOException, InterruptedException {
-    long startTime = System.currentTimeMillis();
-    HttpClient httpClient = HttpClient.newHttpClient();
-    URI uri = URI.create(this.host + "/api/generate");
-    HttpRequest.Builder requestBuilder =
-        getRequestBuilderDefault(uri)
-            .POST(
-                HttpRequest.BodyPublishers.ofString(
-                    Utils.getObjectMapper().writeValueAsString(ollamaRequestModel)));
-    HttpRequest request = requestBuilder.build();
-    if (verbose) logger.info("Asking model: " + ollamaRequestModel);
-    HttpResponse<InputStream> response =
-        httpClient.send(request, HttpResponse.BodyHandlers.ofInputStream());
-    int statusCode = response.statusCode();
-    InputStream responseBodyStream = response.body();
-    StringBuilder responseBuffer = new StringBuilder();
-    try (BufferedReader reader =
-        new BufferedReader(new InputStreamReader(responseBodyStream, StandardCharsets.UTF_8))) {
-      String line;
-      while ((line = reader.readLine()) != null) {
-        if (statusCode == 404) {
-          logger.warn("Status code: 404 (Not Found)");
-          OllamaErrorResponseModel ollamaResponseModel =
-              Utils.getObjectMapper().readValue(line, OllamaErrorResponseModel.class);
-          responseBuffer.append(ollamaResponseModel.getError());
-        } else if (statusCode == 401) {
-          logger.warn("Status code: 401 (Unauthorized)");
-          OllamaErrorResponseModel ollamaResponseModel =
-              Utils.getObjectMapper()
-                  .readValue("{\"error\":\"Unauthorized\"}", OllamaErrorResponseModel.class);
-          responseBuffer.append(ollamaResponseModel.getError());
-        } else {
-          OllamaResponseModel ollamaResponseModel =
-              Utils.getObjectMapper().readValue(line, OllamaResponseModel.class);
-          if (!ollamaResponseModel.isDone()) {
-            responseBuffer.append(ollamaResponseModel.getResponse());
-          }
-        }
-      }
-    }
-
-    if (statusCode != 200) {
-      logger.error("Status code " + statusCode);
-      throw new OllamaBaseException(responseBuffer.toString());
-    } else {
-      long endTime = System.currentTimeMillis();
-      OllamaResult ollamaResult =
-          new OllamaResult(responseBuffer.toString().trim(), endTime - startTime, statusCode);
-      if (verbose) logger.info("Model response: " + ollamaResult);
-      return ollamaResult;
-    }
+        OllamaGenerateEndpointCaller requestCaller = new OllamaGenerateEndpointCaller(host, basicAuth, requestTimeoutSeconds, verbose);
+        return requestCaller.generateSync(ollamaRequestModel);
   }
 
   /**

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/OllamaErrorResponseModel.java

@@ -1,8 +1,6 @@
 package io.github.amithkoujalgi.ollama4j.core.models;
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import com.fasterxml.jackson.annotation.JsonProperty;
-import java.util.List;
 import lombok.Data;
 
 @Data

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/OllamaRequestModel.java

@@ -3,12 +3,15 @@ package io.github.amithkoujalgi.ollama4j.core.models;
 import static io.github.amithkoujalgi.ollama4j.core.utils.Utils.getObjectMapper;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
+
+import io.github.amithkoujalgi.ollama4j.core.utils.OllamaRequestBody;
+
 import java.util.List;
 import java.util.Map;
 import lombok.Data;
 
 @Data
-public class OllamaRequestModel {
+public class OllamaRequestModel implements OllamaRequestBody{
 
   private String model;
   private String prompt;

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/chat/OllamaChatMessage.java

@@ -0,0 +1,42 @@
+package io.github.amithkoujalgi.ollama4j.core.models.chat;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import static io.github.amithkoujalgi.ollama4j.core.utils.Utils.getObjectMapper;
+
+import java.io.File;
+import java.util.List;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+import lombok.NonNull;
+import lombok.RequiredArgsConstructor;
+
+/**
+ * Defines a single Message to be used inside a chat request against the ollama /api/chat endpoint.
+ * 
+ * @see https://github.com/ollama/ollama/blob/main/docs/api.md#generate-a-chat-completion
+ */
+@Data
+@AllArgsConstructor
+@RequiredArgsConstructor
+@NoArgsConstructor
+public class OllamaChatMessage {
+
+    @NonNull
+    private OllamaChatMessageRole role;
+
+    @NonNull
+    private String content;
+
+    private List<File> images;
+    
+      @Override
+  public String toString() {
+    try {
+      return getObjectMapper().writerWithDefaultPrettyPrinter().writeValueAsString(this);
+    } catch (JsonProcessingException e) {
+      throw new RuntimeException(e);
+    }
+  }
+}

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/chat/OllamaChatMessageRole.java

@@ -0,0 +1,19 @@
+package io.github.amithkoujalgi.ollama4j.core.models.chat;
+
+import com.fasterxml.jackson.annotation.JsonValue;
+
+/**
+ * Defines the possible Chat Message roles.
+ */
+public enum OllamaChatMessageRole {
+    SYSTEM("system"),
+    USER("user"),
+    ASSISTANT("assistant");
+
+    @JsonValue
+    private String roleName;
+
+    private OllamaChatMessageRole(String roleName){
+        this.roleName = roleName;
+    }
+}

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/chat/OllamaChatRequestBuilder.java

@@ -0,0 +1,68 @@
+package io.github.amithkoujalgi.ollama4j.core.models.chat;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+import io.github.amithkoujalgi.ollama4j.core.utils.Options;
+
+/**
+ * Helper class for creating {@link OllamaChatRequestModel} objects using the builder-pattern.
+ */
+public class OllamaChatRequestBuilder {
+
+    private OllamaChatRequestBuilder(String model, List<OllamaChatMessage> messages){
+        request = new OllamaChatRequestModel(model, messages);
+    }
+
+    private OllamaChatRequestModel request;
+
+    public static OllamaChatRequestBuilder getInstance(String model){
+        return new OllamaChatRequestBuilder(model, new ArrayList<>());
+    }
+
+    public OllamaChatRequestModel build(){
+        return request;
+    }
+
+    public void reset(){
+        request = new OllamaChatRequestModel(request.getModel(), new ArrayList<>());
+    }
+
+    public OllamaChatRequestBuilder withMessage(OllamaChatMessageRole role, String content, File... images){
+        List<OllamaChatMessage> messages = this.request.getMessages();
+        messages.add(new OllamaChatMessage(role,content,List.of(images)));
+        return this;
+    }
+
+    public OllamaChatRequestBuilder withMessages(List<OllamaChatMessage> messages){
+        this.request.getMessages().addAll(messages);
+        return this;
+    }
+
+    public OllamaChatRequestBuilder withOptions(Options options){
+        this.request.setOptions(options);
+        return this;
+    }
+
+    public OllamaChatRequestBuilder withFormat(String format){
+        this.request.setFormat(format);
+        return this;
+    }
+
+    public OllamaChatRequestBuilder withTemplate(String template){
+        this.request.setTemplate(template);
+        return this;
+    }
+
+    public OllamaChatRequestBuilder withStreaming(){
+        this.request.setStream(true);
+        return this;
+    }
+
+    public OllamaChatRequestBuilder withKeepAlive(String keepAlive){
+        this.request.setKeepAlive(keepAlive);
+        return this;
+    }
+
+}

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/chat/OllamaChatRequestModel.java

@@ -0,0 +1,48 @@
+package io.github.amithkoujalgi.ollama4j.core.models.chat;
+
+import java.util.List;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+
+import io.github.amithkoujalgi.ollama4j.core.utils.OllamaRequestBody;
+import io.github.amithkoujalgi.ollama4j.core.utils.Options;
+
+import static io.github.amithkoujalgi.ollama4j.core.utils.Utils.getObjectMapper;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NonNull;
+import lombok.RequiredArgsConstructor;
+
+/**
+ * Defines a Request to use against the ollama /api/chat endpoint.
+ * 
+ * @see https://github.com/ollama/ollama/blob/main/docs/api.md#generate-a-chat-completion
+ */
+@Data
+@AllArgsConstructor
+@RequiredArgsConstructor
+public class OllamaChatRequestModel implements OllamaRequestBody{
+
+    @NonNull
+    private String model;
+
+    @NonNull
+    private List<OllamaChatMessage> messages;
+
+    private String format;
+    private Options options;
+    private String template;
+    private boolean stream;
+    private String keepAlive;
+
+      @Override
+  public String toString() {
+    try {
+      return getObjectMapper().writerWithDefaultPrettyPrinter().writeValueAsString(this);
+    } catch (JsonProcessingException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+}

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/chat/OllamaChatResponseModel.java

@@ -0,0 +1,21 @@
+package io.github.amithkoujalgi.ollama4j.core.models.chat;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+import java.util.List;
+import lombok.Data;
+
+@Data
+public class OllamaChatResponseModel {
+    private String model;
+    private @JsonProperty("created_at") String createdAt;
+    private OllamaChatMessage message;
+    private boolean done;
+    private List<Integer> context;
+    private @JsonProperty("total_duration") Long totalDuration;
+    private @JsonProperty("load_duration") Long loadDuration;
+    private @JsonProperty("prompt_eval_duration") Long promptEvalDuration;
+    private @JsonProperty("eval_duration") Long evalDuration;
+    private @JsonProperty("prompt_eval_count") Integer promptEvalCount;
+    private @JsonProperty("eval_count") Integer evalCount;
+}

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/chat/OllamaChatResult.java

@@ -0,0 +1,32 @@
+package io.github.amithkoujalgi.ollama4j.core.models.chat;
+
+import java.util.List;
+
+import io.github.amithkoujalgi.ollama4j.core.models.OllamaResult;
+
+/**
+ * Specific chat-API result that contains the chat history sent to the model and appends the answer as {@link OllamaChatResult} given by the
+ * {@link OllamaChatMessageRole#ASSISTANT} role.
+ */
+public class OllamaChatResult extends OllamaResult{
+
+    private List<OllamaChatMessage> chatHistory;
+
+    public OllamaChatResult(String response, long responseTime, int httpStatusCode,
+            List<OllamaChatMessage> chatHistory) {
+        super(response, responseTime, httpStatusCode);
+        this.chatHistory = chatHistory;
+        appendAnswerToChatHistory(response);
+    }
+
+    public List<OllamaChatMessage> getChatHistory() {
+        return chatHistory;
+    } 
+
+    private void appendAnswerToChatHistory(String answer){
+        OllamaChatMessage assistantMessage = new OllamaChatMessage(OllamaChatMessageRole.ASSISTANT, answer);
+        this.chatHistory.add(assistantMessage);
+    }
+    
+    
+}

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/request/OllamaChatEndpointCaller.java

@@ -0,0 +1,44 @@
+package io.github.amithkoujalgi.ollama4j.core.models.request;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+
+import io.github.amithkoujalgi.ollama4j.core.models.BasicAuth;
+import io.github.amithkoujalgi.ollama4j.core.models.chat.OllamaChatResponseModel;
+import io.github.amithkoujalgi.ollama4j.core.utils.Utils;
+
+/**
+ * Specialization class for requests
+ */
+public class OllamaChatEndpointCaller extends OllamaEndpointCaller{
+
+    private static final Logger LOG = LoggerFactory.getLogger(OllamaChatEndpointCaller.class);
+
+    public OllamaChatEndpointCaller(String host, BasicAuth basicAuth, long requestTimeoutSeconds, boolean verbose) {
+        super(host, basicAuth, requestTimeoutSeconds, verbose);
+    }
+
+    @Override
+    protected String getEndpointSuffix() {
+        return "/api/chat";
+    }
+
+    @Override
+    protected boolean parseResponseAndAddToBuffer(String line, StringBuilder responseBuffer) {
+                try {
+                    OllamaChatResponseModel ollamaResponseModel = Utils.getObjectMapper().readValue(line, OllamaChatResponseModel.class);
+                    responseBuffer.append(ollamaResponseModel.getMessage().getContent());
+                    return ollamaResponseModel.isDone();
+                } catch (JsonProcessingException e) {
+                    LOG.error("Error parsing the Ollama chat response!",e);
+                    return true;
+                }         
+    }
+
+
+
+    
+
+}

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/request/OllamaEndpointCaller.java

@@ -0,0 +1,150 @@
+package io.github.amithkoujalgi.ollama4j.core.models.request;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.nio.charset.StandardCharsets;
+import java.time.Duration;
+import java.util.Base64;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import io.github.amithkoujalgi.ollama4j.core.OllamaAPI;
+import io.github.amithkoujalgi.ollama4j.core.exceptions.OllamaBaseException;
+import io.github.amithkoujalgi.ollama4j.core.models.BasicAuth;
+import io.github.amithkoujalgi.ollama4j.core.models.OllamaErrorResponseModel;
+import io.github.amithkoujalgi.ollama4j.core.models.OllamaResult;
+import io.github.amithkoujalgi.ollama4j.core.utils.OllamaRequestBody;
+import io.github.amithkoujalgi.ollama4j.core.utils.Utils;
+
+/**
+ * Abstract helperclass to call the ollama api server.
+ */
+public abstract class OllamaEndpointCaller {
+    
+    private static final Logger LOG = LoggerFactory.getLogger(OllamaAPI.class);
+
+    private String host;
+    private BasicAuth basicAuth;
+    private long requestTimeoutSeconds;
+    private boolean verbose;
+
+    public OllamaEndpointCaller(String host, BasicAuth basicAuth, long requestTimeoutSeconds, boolean verbose) {
+        this.host = host;
+        this.basicAuth = basicAuth;
+        this.requestTimeoutSeconds = requestTimeoutSeconds;
+        this.verbose = verbose;
+    }
+
+    protected abstract String getEndpointSuffix();
+
+    protected abstract boolean parseResponseAndAddToBuffer(String line, StringBuilder responseBuffer);
+
+    
+    /**
+     * Calls the api server on the given host and endpoint suffix asynchronously, aka waiting for the response.
+     * 
+     * @param body POST body payload
+     * @return result answer given by the assistant
+     * @throws OllamaBaseException any response code than 200 has been returned
+     * @throws IOException in case the responseStream can not be read
+     * @throws InterruptedException in case the server is not reachable or network issues happen
+     */
+    public OllamaResult generateSync(OllamaRequestBody body)  throws OllamaBaseException, IOException, InterruptedException{
+
+        // Create Request
+    long startTime = System.currentTimeMillis();
+    HttpClient httpClient = HttpClient.newHttpClient();
+    URI uri = URI.create(this.host + getEndpointSuffix());
+    HttpRequest.Builder requestBuilder =
+        getRequestBuilderDefault(uri)
+            .POST(
+                body.getBodyPublisher());
+    HttpRequest request = requestBuilder.build();
+    if (this.verbose) LOG.info("Asking model: " + body.toString());
+    HttpResponse<InputStream> response =
+        httpClient.send(request, HttpResponse.BodyHandlers.ofInputStream());
+    
+        
+        int statusCode = response.statusCode();
+    InputStream responseBodyStream = response.body();
+    StringBuilder responseBuffer = new StringBuilder();
+    try (BufferedReader reader =
+        new BufferedReader(new InputStreamReader(responseBodyStream, StandardCharsets.UTF_8))) {
+      String line;
+      while ((line = reader.readLine()) != null) {
+        if (statusCode == 404) {
+            LOG.warn("Status code: 404 (Not Found)");
+          OllamaErrorResponseModel ollamaResponseModel =
+              Utils.getObjectMapper().readValue(line, OllamaErrorResponseModel.class);
+          responseBuffer.append(ollamaResponseModel.getError());
+        } else if (statusCode == 401) {
+            LOG.warn("Status code: 401 (Unauthorized)");
+          OllamaErrorResponseModel ollamaResponseModel =
+              Utils.getObjectMapper()
+                  .readValue("{\"error\":\"Unauthorized\"}", OllamaErrorResponseModel.class);
+          responseBuffer.append(ollamaResponseModel.getError());
+        } else {
+          boolean finished = parseResponseAndAddToBuffer(line,responseBuffer);
+            if (finished) {
+              break;
+            }
+        }
+      }
+    }
+
+    if (statusCode != 200) {
+        LOG.error("Status code " + statusCode);
+      throw new OllamaBaseException(responseBuffer.toString());
+    } else {
+      long endTime = System.currentTimeMillis();
+      OllamaResult ollamaResult =
+          new OllamaResult(responseBuffer.toString().trim(), endTime - startTime, statusCode);
+      if (verbose) LOG.info("Model response: " + ollamaResult);
+      return ollamaResult;
+    }
+  }
+
+    /**
+   * Get default request builder.
+   *
+   * @param uri URI to get a HttpRequest.Builder
+   * @return HttpRequest.Builder
+   */
+  private HttpRequest.Builder getRequestBuilderDefault(URI uri) {
+    HttpRequest.Builder requestBuilder =
+        HttpRequest.newBuilder(uri)
+            .header("Content-Type", "application/json")
+            .timeout(Duration.ofSeconds(this.requestTimeoutSeconds));
+    if (isBasicAuthCredentialsSet()) {
+      requestBuilder.header("Authorization", getBasicAuthHeaderValue());
+    }
+    return requestBuilder;
+  }
+
+  /**
+   * Get basic authentication header value.
+   *
+   * @return basic authentication header value (encoded credentials)
+   */
+  private String getBasicAuthHeaderValue() {
+    String credentialsToEncode = this.basicAuth.getUsername() + ":" + this.basicAuth.getPassword();
+    return "Basic " + Base64.getEncoder().encodeToString(credentialsToEncode.getBytes());
+  }
+
+  /**
+   * Check if Basic Auth credentials set.
+   *
+   * @return true when Basic Auth credentials set
+   */
+  private boolean isBasicAuthCredentialsSet() {
+    return this.basicAuth != null;
+  }
+    
+}

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/request/OllamaGenerateEndpointCaller.java

@@ -0,0 +1,40 @@
+package io.github.amithkoujalgi.ollama4j.core.models.request;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+
+import io.github.amithkoujalgi.ollama4j.core.models.BasicAuth;
+import io.github.amithkoujalgi.ollama4j.core.models.OllamaResponseModel;
+import io.github.amithkoujalgi.ollama4j.core.utils.Utils;
+
+public class OllamaGenerateEndpointCaller extends OllamaEndpointCaller{
+
+    private static final Logger LOG = LoggerFactory.getLogger(OllamaGenerateEndpointCaller.class);
+
+    public OllamaGenerateEndpointCaller(String host, BasicAuth basicAuth, long requestTimeoutSeconds, boolean verbose) {
+        super(host, basicAuth, requestTimeoutSeconds, verbose);   
+    }
+
+    @Override
+    protected String getEndpointSuffix() {
+        return "/api/generate";
+    }
+
+    @Override
+    protected boolean parseResponseAndAddToBuffer(String line, StringBuilder responseBuffer) {
+                try {
+                    OllamaResponseModel ollamaResponseModel = Utils.getObjectMapper().readValue(line, OllamaResponseModel.class);
+                    responseBuffer.append(ollamaResponseModel.getResponse());
+                    return ollamaResponseModel.isDone();
+                } catch (JsonProcessingException e) {
+                    LOG.error("Error parsing the Ollama chat response!",e);
+                    return true;
+                }         
+    }
+
+    
+    
+    
+}

src/main/java/io/github/amithkoujalgi/ollama4j/core/utils/OllamaRequestBody.java

@@ -0,0 +1,28 @@
+package io.github.amithkoujalgi.ollama4j.core.utils;
+
+import java.net.http.HttpRequest.BodyPublisher;
+import java.net.http.HttpRequest.BodyPublishers;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.core.JsonProcessingException;
+
+/**
+ * Interface to represent a OllamaRequest as HTTP-Request Body via {@link BodyPublishers}.
+ */
+public interface OllamaRequestBody {
+    
+    /**
+     * Transforms the OllamaRequest Object to a JSON Object via Jackson.
+     * 
+     * @return JSON representation of a OllamaRequest
+     */
+    @JsonIgnore
+    default BodyPublisher getBodyPublisher(){
+                try {
+          return BodyPublishers.ofString(
+                      Utils.getObjectMapper().writeValueAsString(this));
+        } catch (JsonProcessingException e) {
+          throw new IllegalArgumentException("Request not Body convertible.",e);
+        }
+    }
+}

src/test/java/io/github/amithkoujalgi/ollama4j/integrationtests/TestRealAPIs.java

@@ -5,6 +5,10 @@ import static org.junit.jupiter.api.Assertions.*;
 import io.github.amithkoujalgi.ollama4j.core.OllamaAPI;
 import io.github.amithkoujalgi.ollama4j.core.exceptions.OllamaBaseException;
 import io.github.amithkoujalgi.ollama4j.core.models.OllamaResult;
+import io.github.amithkoujalgi.ollama4j.core.models.chat.OllamaChatMessageRole;
+import io.github.amithkoujalgi.ollama4j.core.models.chat.OllamaChatRequestBuilder;
+import io.github.amithkoujalgi.ollama4j.core.models.chat.OllamaChatRequestModel;
+import io.github.amithkoujalgi.ollama4j.core.models.chat.OllamaChatResult;
 import io.github.amithkoujalgi.ollama4j.core.utils.OptionsBuilder;
 import java.io.File;
 import java.io.IOException;
@@ -118,6 +122,46 @@ class TestRealAPIs {
     }
   }
 
+  @Test
+  @Order(3)
+  void testChat() {
+    testEndpointReachability();
+    try {
+      OllamaChatRequestBuilder builder = OllamaChatRequestBuilder.getInstance(config.getModel());
+      OllamaChatRequestModel requestModel = builder.withMessage(OllamaChatMessageRole.USER, "What is the capital of France?")
+             .withMessage(OllamaChatMessageRole.ASSISTANT, "Should be Paris!")
+             .withMessage(OllamaChatMessageRole.USER,"And what is the second larges city?")
+             .build();
+
+      OllamaChatResult chatResult = ollamaAPI.chat(requestModel);
+      assertNotNull(chatResult);
+      assertFalse(chatResult.getResponse().isBlank());
+      assertEquals(4,chatResult.getChatHistory().size());
+    } catch (IOException | OllamaBaseException | InterruptedException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  @Test
+  @Order(3)
+  void testChatWithSystemPrompt() {
+    testEndpointReachability();
+    try {
+      OllamaChatRequestBuilder builder = OllamaChatRequestBuilder.getInstance(config.getModel());
+      OllamaChatRequestModel requestModel = builder.withMessage(OllamaChatMessageRole.SYSTEM, "You are a silent bot that only says 'NI'. Do not say anything else under any circumstances!")
+             .withMessage(OllamaChatMessageRole.USER,"What is the capital of France? And what's France's connection with Mona Lisa?")
+             .build();
+
+      OllamaChatResult chatResult = ollamaAPI.chat(requestModel);
+      assertNotNull(chatResult);
+      assertFalse(chatResult.getResponse().isBlank());
+      assertTrue(chatResult.getResponse().startsWith("NI"));
+      assertEquals(3,chatResult.getChatHistory().size());
+    } catch (IOException | OllamaBaseException | InterruptedException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
   @Test
   @Order(3)
   void testAskModelWithOptionsAndImageFiles() {