# Sayna Python SDK

Python SDK for Sayna's real-time voice interaction API. Send audio for speech recognition, receive synthesized speech, and manage voice sessions from your Python applications.

## Features

- 🎤 **Speech-to-Text**: Real-time transcription with support for multiple providers (Deepgram, Google, etc.)
- 🔊 **Text-to-Speech**: High-quality voice synthesis with various TTS providers (ElevenLabs, Google, etc.)
- 🔌 **WebSocket Connection**: Async/await support with aiohttp
- 🌐 **REST API**: Standalone endpoints for health checks, voice catalog, TTS synthesis, and SIP hooks management
- 🔐 **Webhook Receiver**: Secure verification and parsing of SIP webhooks with HMAC-SHA256 signatures
- ✅ **Type Safety**: Full type hints with Pydantic models
- 🚀 **Easy to Use**: Simple, intuitive API
- 📦 **Modern Python**: Built for Python 3.9+

## Installation

```bash
pip install sayna-client
```

## Quick Start

```python
import asyncio
from sayna_client import SaynaClient, STTConfig, TTSConfig

async def main():
    # Initialize the client with configs
    client = SaynaClient(
        url="https://api.sayna.ai",
        stt_config=STTConfig(
            provider="deepgram",
            model="nova-2"
        ),
        tts_config=TTSConfig(
            provider="cartesia",
            voice_id="example-voice"
        ),
        api_key="your-api-key"
    )

    # Register callbacks
    client.register_on_stt_result(lambda result: print(f"Transcription: {result.transcript}"))
    client.register_on_tts_audio(lambda audio: print(f"Received {len(audio)} bytes of audio"))

    # Connect and interact
    await client.connect()
    await client.speak("Hello, world!")
    await client.disconnect()

if __name__ == "__main__":
    asyncio.run(main())
```

## API

### REST API Methods

These methods use HTTP endpoints and don't require an active WebSocket connection:

#### `await client.health()`

Performs a health check on the Sayna server.

**Returns**: `HealthResponse` - Response object with `status` field ("OK" when healthy).

**Example**:
```python
health = await client.health()
print(health.status)  # "OK"
```

---

#### `await client.get_voices()`

Retrieves the catalogue of text-to-speech voices grouped by provider.

**Returns**: `dict[str, list[VoiceDescriptor]]` - Dictionary where keys are provider names and values are lists of voice descriptors.

**Example**:
```python
voices = await client.get_voices()
for provider, voice_list in voices.items():
    print(f"{provider}:", [v.name for v in voice_list])
```

---

#### `await client.speak_rest(text, tts_config)`

Synthesizes text into audio using the REST API. This is a standalone method that doesn't require an active WebSocket connection.

| Parameter | Type | Purpose |
| --- | --- | --- |
| `text` | `str` | Text to synthesize (must be non-empty). |
| `tts_config` | `TTSConfig` | Text-to-speech provider configuration. |

**Returns**: `tuple[bytes, dict[str, str]]` - Tuple of (audio_data, response_headers). Headers include: Content-Type, Content-Length, x-audio-format, x-sample-rate.

**Example**:
```python
audio_data, headers = await client.speak_rest("Hello, world!", TTSConfig(
    provider="elevenlabs",
    voice_id="21m00Tcm4TlvDq8ikWAM",
    model="eleven_turbo_v2",
    speaking_rate=1.0,
    audio_format="mp3",
    sample_rate=24000,
    connection_timeout=30,
    request_timeout=60,
    pronunciations=[]
))
print(f"Received {len(audio_data)} bytes of {headers['Content-Type']}")
```

---

#### `await client.get_livekit_token(room_name, participant_name, participant_identity)`

Issues a LiveKit access token for a participant.

| Parameter | Type | Purpose |
| --- | --- | --- |
| `room_name` | `str` | LiveKit room to join or create. |
| `participant_name` | `str` | Display name for the participant. |
| `participant_identity` | `str` | Unique identifier for the participant. |

**Returns**: `LiveKitTokenResponse` - Object containing token, room name, participant identity, and LiveKit URL.

**Example**:
```python
token_info = await client.get_livekit_token(
    "my-room",
    "John Doe",
    "user-123"
)
print("Token:", token_info.token)
print("LiveKit URL:", token_info.livekit_url)
```

---

#### `await client.get_sip_hooks()`

Retrieves all configured SIP webhook hooks from the runtime cache.

**Returns**: `SipHooksResponse` - Object containing the list of configured SIP hooks.

**Example**:
```python
hooks = await client.get_sip_hooks()
for hook in hooks.hooks:
    print(f"{hook.host} -> {hook.url}")
```

---

#### `await client.set_sip_hooks(hooks)`

Adds or replaces SIP webhook hooks. Existing hooks with matching hosts (case-insensitive) are replaced.

| Parameter | Type | Purpose |
| --- | --- | --- |
| `hooks` | `list[SipHook]` | List of SipHook objects to add or replace. |

**Returns**: `SipHooksResponse` - Object containing the merged list of all hooks (existing + new).

**Example**:
```python
from sayna_client import SipHook

hooks = [
    SipHook(host="example.com", url="https://webhook.example.com/events"),
    SipHook(host="another.com", url="https://webhook.another.com/events"),
]
response = await client.set_sip_hooks(hooks)
print(f"Total hooks: {len(response.hooks)}")
```

---

### WebSocket API Methods

These methods require an active WebSocket connection:

#### `SaynaClient(url, stt_config, tts_config, livekit_config=None, without_audio=False, api_key=None)`

Creates a new SaynaClient instance.

| Parameter | Type | Default | Purpose |
| --- | --- | --- | --- |
| `url` | `str` | - | Sayna server URL (http://, https://, ws://, or wss://). |
| `stt_config` | `STTConfig` | - | Speech-to-text provider configuration. |
| `tts_config` | `TTSConfig` | - | Text-to-speech provider configuration. |
| `livekit_config` | `LiveKitConfig` (optional) | `None` | Optional LiveKit room configuration. |
| `without_audio` | `bool` | `False` | Disable audio streaming. |
| `api_key` | `str` (optional) | `None` | API key for authentication. |

---

#### `await client.connect()`

Establishes WebSocket connection and sends initial configuration. Resolves when server sends ready message.

---

#### `client.register_on_stt_result(callback)`

Registers a callback for speech-to-text transcription results.

**Example**:
```python
def handle_stt(result):
    print(f"Transcription: {result.transcript}")

client.register_on_stt_result(handle_stt)
```

---

#### `client.register_on_tts_audio(callback)`

Registers a callback for text-to-speech audio data.

**Example**:
```python
def handle_audio(audio_data: bytes):
    print(f"Received {len(audio_data)} bytes of audio")

client.register_on_tts_audio(handle_audio)
```

---

#### `client.register_on_error(callback)`

Registers a callback for error messages.

---

#### `client.register_on_message(callback)`

Registers a callback for participant messages.

---

#### `client.register_on_participant_disconnected(callback)`

Registers a callback for participant disconnection events.

---

#### `client.register_on_tts_playback_complete(callback)`

Registers a callback for TTS playback completion events.

---

#### `await client.speak(text, flush=True, allow_interruption=True)`

Sends text to be synthesized as speech.

| Parameter | Type | Default | Purpose |
| --- | --- | --- | --- |
| `text` | `str` | - | Text to synthesize. |
| `flush` | `bool` | `True` | Clear TTS queue before speaking. |
| `allow_interruption` | `bool` | `True` | Allow speech to be interrupted. |

**Example**:
```python
await client.speak("Hello, world!")
await client.speak("Important message", flush=True, allow_interruption=False)
```

---

#### `await client.on_audio_input(audio_data)`

Sends raw audio data (bytes) to the server for speech recognition.

**Example**:
```python
await client.on_audio_input(audio_bytes)
```

---

#### `await client.send_message(message, role, topic="messages", debug=None)`

Sends a message to the Sayna session with role and optional metadata.

| Parameter | Type | Default | Purpose |
| --- | --- | --- | --- |
| `message` | `str` | - | Message content. |
| `role` | `str` | - | Sender role (e.g., 'user', 'assistant'). |
| `topic` | `str` | `"messages"` | LiveKit topic/channel. |
| `debug` | `dict` (optional) | `None` | Optional debug metadata. |

---

#### `await client.clear()`

Clears the text-to-speech queue.

---

#### `await client.tts_flush(allow_interruption=True)`

Flushes the TTS queue by sending an empty speak command.

---

#### `await client.disconnect()`

Disconnects from the WebSocket server and cleans up resources.

---

#### Properties

- **`client.ready`**: Boolean indicating whether the connection is ready (received ready message).
- **`client.connected`**: Boolean indicating whether the WebSocket is connected.
- **`client.livekit_room_name`**: LiveKit room name (available after ready when LiveKit is enabled).
- **`client.livekit_url`**: LiveKit URL (available after ready).
- **`client.sayna_participant_identity`**: Sayna participant identity (available after ready when LiveKit is enabled).
- **`client.sayna_participant_name`**: Sayna participant name (available after ready when LiveKit is enabled).

---

### Webhook Receiver

The `WebhookReceiver` class securely verifies and parses cryptographically signed webhooks from the Sayna SIP service.

#### Security Features

- **HMAC-SHA256 Signature Verification**: Ensures webhook authenticity
- **Constant-Time Comparison**: Prevents timing attack vulnerabilities
- **Replay Protection**: 5-minute timestamp window prevents replay attacks
- **Strict Validation**: Comprehensive checks on all required fields

#### `WebhookReceiver(secret=None)`

Creates a new webhook receiver instance.

| Parameter | Type | Default | Purpose |
| --- | --- | --- | --- |
| `secret` | `str` (optional) | `None` | HMAC signing secret (min 16 chars). Falls back to `SAYNA_WEBHOOK_SECRET` env variable. |

**Example**:
```python
from sayna_client import WebhookReceiver

# Explicit secret
receiver = WebhookReceiver("your-secret-key-min-16-chars")

# Or from environment variable (SAYNA_WEBHOOK_SECRET)
receiver = WebhookReceiver()
```

---

#### `receiver.receive(headers, body)`

Verifies and parses an incoming SIP webhook.

| Parameter | Type | Purpose |
| --- | --- | --- |
| `headers` | `dict` | HTTP request headers (case-insensitive). |
| `body` | `str` | Raw request body as string (not parsed JSON). |

**Returns**: `WebhookSIPOutput` - Validated webhook payload with fields:
- `participant`: Object with `identity`, `sid`, and optional `name`
- `room`: Object with `name` and `sid`
- `from_phone_number`: Caller's phone number (E.164 format)
- `to_phone_number`: Called phone number (E.164 format)
- `room_prefix`: Room name prefix configured in Sayna
- `sip_host`: SIP domain extracted from the To header

**Raises**: `SaynaValidationError` if signature verification fails or payload is invalid.

---

#### Flask Example

```python
from flask import Flask, request, jsonify
from sayna_client import WebhookReceiver, SaynaValidationError

app = Flask(__name__)
receiver = WebhookReceiver("your-secret-key-min-16-chars")

@app.route("/webhook", methods=["POST"])
def webhook():
    try:
        # CRITICAL: Pass raw body, not parsed JSON
        body = request.get_data(as_text=True)
        webhook = receiver.receive(request.headers, body)

        print(f"From: {webhook.from_phone_number}")
        print(f"To: {webhook.to_phone_number}")
        print(f"Room: {webhook.room.name}")
        print(f"SIP Host: {webhook.sip_host}")
        print(f"Participant: {webhook.participant.identity}")

        return jsonify({"received": True}), 200
    except SaynaValidationError as error:
        print(f"Webhook verification failed: {error}")
        return jsonify({"error": "Invalid signature"}), 401
```

---

#### FastAPI Example

```python
from fastapi import FastAPI, Request, HTTPException
from sayna_client import WebhookReceiver, SaynaValidationError

app = FastAPI()
receiver = WebhookReceiver()  # Uses SAYNA_WEBHOOK_SECRET env variable

@app.post("/webhook")
async def webhook(request: Request):
    try:
        body = await request.body()
        body_str = body.decode("utf-8")
        webhook = receiver.receive(dict(request.headers), body_str)

        # Process webhook...
        return {"received": True}
    except SaynaValidationError as error:
        raise HTTPException(status_code=401, detail=str(error))
```

---

#### Important Notes

- **Raw Body Required**: You MUST pass the raw request body string, not the parsed JSON object. The signature is computed over the exact bytes received, so any formatting changes will cause verification to fail.

- **Case-Insensitive Headers**: Header names are case-insensitive in HTTP. The receiver handles both `X-Sayna-Signature` and `x-sayna-signature` correctly.

- **Secret Security**: Never commit secrets to version control. Use environment variables or a secret management system. Generate a secure secret with: `openssl rand -hex 32`

---

## Development

### Setup

```bash
# Create a virtual environment
python -m venv .venv

# Activate it
source .venv/bin/activate  # On Linux/macOS
# .venv\Scripts\activate  # On Windows

# Install development dependencies
pip install -e ".[dev]"
```

> **Tip**: For faster dependency installation, you can use [uv](https://github.com/astral-sh/uv):
> ```bash
> pip install uv
> uv pip install -e ".[dev]"
> ```

### Running Tests

```bash
# Run all tests
pytest

# Run with coverage
pytest --cov=sayna_client --cov-report=html

# Run specific test file
pytest tests/test_client.py
```

### Type Checking

```bash
mypy src/sayna_client
```

### Linting and Formatting

This project uses [Ruff](https://github.com/astral-sh/ruff) for linting and formatting:

```bash
# Check code
ruff check .

# Format code
ruff format .

# Fix auto-fixable issues
ruff check --fix .
```

## Requirements

- Python 3.9 or higher
- aiohttp >= 3.9.0
- pydantic >= 2.0.0

## Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

## Support

For issues and questions, please visit the [GitHub Issues](https://github.com/SaynaAi/saysdk/issues) page.
