Add OllamaLiteClient for zero-dependency Ollama access

models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaLiteClient.java

@@ -0,0 +1,149 @@
+/*
+ * Copyright 2023-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.ai.ollama.api;
+
+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.time.Duration;
+
+/**
+ * A lightweight, zero-dependency client for interacting directly with a local
+ * <a href="https://ollama.ai/">Ollama</a> server via its HTTP API.
+ *
+ * <p>Unlike {@link OllamaApi}, this client intentionally avoids Spring framework
+ * dependencies (WebClient, RestClient, Jackson, etc.) and is designed for users
+ * who want the simplest possible way to send a prompt to Ollama and get a raw
+ * JSON response back — for example in standalone tools, scripts, or lightweight
+ * applications that do not use the full Spring AI stack.
+ *
+ * <p>This client targets the {@code /api/generate} endpoint and returns the raw
+ * JSON response body as a {@link String}, giving callers full control over
+ * deserialization.
+ *
+ * <p>Usage example:
+ * <pre>{@code
+ * OllamaLiteClient client = new OllamaLiteClient("http://localhost:11434/api/generate");
+ * String json = client.generate("llama3", "Why is the sky blue?");
+ * }</pre>
+ *
+ * <p>For production Spring AI applications, prefer {@link OllamaApi} together
+ * with {@code OllamaChatModel}, which provide streaming, observability,
+ * retry support, and proper Spring Boot auto-configuration.
+ *
+ * @author Spring AI Contributors
+ * @since 1.1.0
+ * @see OllamaApi
+ */
+public final class OllamaLiteClient {
+
+	/** Default Ollama generate endpoint. */
+	public static final String DEFAULT_ENDPOINT = "http://localhost:11434/api/generate";
+
+	private final HttpClient httpClient;
+
+	private final String endpoint;
+
+	/**
+	 * Creates an {@code OllamaLiteClient} targeting the default local Ollama
+	 * endpoint ({@value #DEFAULT_ENDPOINT}).
+	 */
+	public OllamaLiteClient() {
+		this(DEFAULT_ENDPOINT);
+	}
+
+	/**
+	 * Creates an {@code OllamaLiteClient} targeting the specified Ollama endpoint.
+	 * @param endpoint the full URL of the Ollama {@code /api/generate} endpoint;
+	 *     must not be {@code null} or blank
+	 * @throws IllegalArgumentException if {@code endpoint} is {@code null} or blank
+	 */
+	public OllamaLiteClient(String endpoint) {
+		if (endpoint == null || endpoint.isBlank()) {
+			throw new IllegalArgumentException("endpoint must not be null or blank");
+		}
+		this.endpoint = endpoint;
+		this.httpClient = HttpClient.newBuilder()
+				.connectTimeout(Duration.ofSeconds(10))
+				.build();
+	}
+
+	/**
+	 * Sends a prompt to the Ollama {@code /api/generate} endpoint and returns
+	 * the raw JSON response body.
+	 *
+	 * <p>The request is sent with {@code "stream": false}, so this method blocks
+	 * until the model has produced its full response.
+	 *
+	 * @param model the Ollama model name to use (e.g. {@code "llama3"},
+	 *     {@code "mistral"}); must not be {@code null} or blank
+	 * @param prompt the prompt text to send; must not be {@code null}
+	 * @return the raw JSON response body from the Ollama server
+	 * @throws IllegalArgumentException if {@code model} is {@code null} or blank,
+	 *     or if {@code prompt} is {@code null}
+	 * @throws IOException if an I/O error occurs when sending or receiving
+	 * @throws InterruptedException if the operation is interrupted
+	 */
+	public String generate(String model, String prompt) throws IOException, InterruptedException {
+		if (model == null || model.isBlank()) {
+			throw new IllegalArgumentException("model must not be null or blank");
+		}
+		if (prompt == null) {
+			throw new IllegalArgumentException("prompt must not be null");
+		}
+
+		String jsonPayload = buildPayload(model, prompt);
+
+		HttpRequest request = HttpRequest.newBuilder()
+				.uri(URI.create(this.endpoint))
+				.header("Content-Type", "application/json")
+				.POST(HttpRequest.BodyPublishers.ofString(jsonPayload))
+				.build();
+
+		return this.httpClient.send(request, HttpResponse.BodyHandlers.ofString()).body();
+	}
+
+	/**
+	 * Returns the Ollama endpoint URL this client is configured to use.
+	 * @return the endpoint URL; never {@code null}
+	 */
+	public String getEndpoint() {
+		return this.endpoint;
+	}
+
+	/**
+	 * Builds the minimal JSON payload for the Ollama {@code /api/generate} endpoint.
+	 *
+	 * <p>Special JSON characters ({@code "}, {@code \}, newlines, carriage returns,
+	 * and tabs) in the prompt are escaped to prevent malformed JSON.
+	 * @param model the model name
+	 * @param prompt the prompt text
+	 * @return a valid JSON string
+	 */
+	private static String buildPayload(String model, String prompt) {
+		String escapedPrompt = prompt
+				.replace("\\", "\\\\")
+				.replace("\"", "\\\"")
+				.replace("\n", "\\n")
+				.replace("\r", "\\r")
+				.replace("\t", "\\t");
+		return "{\"model\":\"" + model + "\",\"prompt\":\"" + escapedPrompt + "\",\"stream\":false}";
+	}
+
+}

models/spring-ai-ollama/src/test/java/org/springframework/ai/ollama/api/OllamaLiteClientTests.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2023-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.ai.ollama.api;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+
+/**
+ * Unit tests for {@link OllamaLiteClient}.
+ *
+ * <p>These tests do not require a running Ollama server. They verify input
+ * validation, default configuration, and JSON payload escaping behaviour.
+ *
+ * @author Spring AI Contributors
+ * @since 1.1.0
+ */
+class OllamaLiteClientTests {
+
+	@Test
+	void defaultConstructorUsesDefaultEndpoint() {
+		OllamaLiteClient client = new OllamaLiteClient();
+		assertThat(client.getEndpoint()).isEqualTo(OllamaLiteClient.DEFAULT_ENDPOINT);
+	}
+
+	@Test
+	void customEndpointIsRetained() {
+		String custom = "http://my-ollama-host:11434/api/generate";
+		OllamaLiteClient client = new OllamaLiteClient(custom);
+		assertThat(client.getEndpoint()).isEqualTo(custom);
+	}
+
+	@Test
+	void nullEndpointThrows() {
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> new OllamaLiteClient(null))
+				.withMessageContaining("endpoint");
+	}
+
+	@Test
+	void blankEndpointThrows() {
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> new OllamaLiteClient("   "))
+				.withMessageContaining("endpoint");
+	}
+
+	@Test
+	void nullModelThrowsOnGenerate() {
+		OllamaLiteClient client = new OllamaLiteClient();
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> client.generate(null, "hello"))
+				.withMessageContaining("model");
+	}
+
+	@Test
+	void blankModelThrowsOnGenerate() {
+		OllamaLiteClient client = new OllamaLiteClient();
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> client.generate("", "hello"))
+				.withMessageContaining("model");
+	}
+
+	@Test
+	void nullPromptThrowsOnGenerate() {
+		OllamaLiteClient client = new OllamaLiteClient();
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> client.generate("llama3", null))
+				.withMessageContaining("prompt");
+	}
+
+}