# Spring Boot OpenAI Streaming Integration

This Spring Boot application demonstrates real-time streaming integration with OpenAI's API using Spring AI. It provides a simple endpoint that streams AI responses using Spring WebFlux.

## Prerequisites

- Java 17 or higher
- Maven
- OpenAI API key

All necessary dependencies including Spring Boot starters for web, webflux, and OpenAI are declared in the Maven pom.xml.

## Configuration

1. Create an `application.properties` or `application.yml` file in `src/main/resources`
2. Add your OpenAI API key:

```properties
spring.ai.openai.api-key=your-api-key-here
```

## Running the Application

1. Clone this repository
2. Configure your OpenAI API key as described above
3. Run the application:
```bash
./mvnw spring-boot:run
```

The application will start on port 8080 by default.

## Usage

The application exposes a streaming endpoint that returns OpenAI responses as a reactive stream.

### Endpoint

```
GET /ai/generateStream
```

#### Parameters
- `message` (optional): The input message to send to OpenAI
    - Default value: "Tell me a joke"

#### Testing with curl

You can test the streaming endpoint using curl. The following command will stream the response and format it using `jq`:

```bash
curl localhost:8080/ai/generateStream | sed 's/data://' | jq .
```

## Implementation Details

The application uses:
- Spring WebFlux for reactive streaming
- Spring AI's OpenAI integration for AI model interaction

The main components are:
1. `OpenAiStreamingApplication`: The Spring Boot application entry point
2. `ChatController`: REST controller handling the streaming endpoint

### Code Details

The streaming endpoint is implemented as follows:

```java
@GetMapping(value = "/generateStream", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
public Flux<ChatResponse> generateStream(
       @RequestParam(value = "message", defaultValue = "Tell me a joke") String message) {
    return chatModel.stream(new Prompt(new UserMessage(message)));
}
```

Key points:
- The endpoint uses `MediaType.TEXT_EVENT_STREAM_VALUE` to indicate that the response will be streamed as text events. 
- Returns a `Flux<ChatResponse>` which is Spring WebFlux's reactive type for handling a stream of multiple elements.
- Takes an optional `message` parameter with a default value of "Tell me a joke".
- Uses Spring AI's `chatModel.stream()` method which returns a reactive stream of responses from OpenAI.
- The `Prompt` and `UserMessage` classes are provided by Spring AI to structure the request to OpenAI.

When called, this endpoint:
1. Takes the user's input message (or uses the default)
2. Wraps it in a Spring AI `Prompt` object
3. Streams the AI's response back to the client in real-time
4. Each response chunk is automatically serialized to JSON