Chat Implementation

This guide walks you through implementing a complete text chat interface with Dasha BlackBox agents using WebSockets. You’ll learn how to establish connections, send messages, receive responses, and handle the full conversation lifecycle.

Prerequisites

Before starting, ensure you have:

Web Integration Token: Generated from your agent’s web integration settings
Agent Configured: Agent created and enabled with chat capabilities
Development Environment: Node.js, browser, or your preferred runtime

Quick Setup: If you haven’t created a web integration yet, see Web Widget Embedding for instructions on creating integrations and generating tokens.

Step 1: Install Dependencies

You only need a WebSocket client library:

Browser: Native WebSocket API (no installation needed)
Node.js: ws package (npm install ws)

Step 2: Create Connection

class ChatConnection {
  private ws: WebSocket | null = null;
  private messageHandlers: Map<string, Function> = new Map();
  
  constructor(
    private serverUrl: string,
    private token: string
  ) {}
  
  connect() {
    const wsUrl = `wss://${this.serverUrl.replace(/^https?:\/\//, '')}/api/v1/ws/webCall?token=${encodeURIComponent(this.token)}`;
    
    this.ws = new WebSocket(wsUrl);
    
    this.ws.onopen = () => {
      // Send initialization message
      this.send({
        type: 'initialize',
        timestamp: new Date().toISOString(),
        request: {
          callType: 'chat',
          additionalData: {}
        }
      });
    };
    
    this.ws.onmessage = (event) => {
      const message = JSON.parse(event.data);
      this.handleMessage(message);
    };
    
    this.ws.onerror = (error) => {
      console.error('WebSocket error:', error);
    };
    
    this.ws.onclose = () => {
      console.log('WebSocket closed');
    };
  }
  
  private handleMessage(message: any) {
    switch (message.type) {
      case 'event':
        if (message.name === 'connection') {
          console.log('Connection established');
        }
        break;
        
      case 'text':
        const text = message.content?.text;
        if (text && message.content?.source === 'assistant') {
          // Agent message received
          this.onMessage?.(text);
        }
        break;
        
      case 'error':
        console.error('Error:', message);
        break;
        
      case 'conversationResult':
        console.log('Conversation ended:', message.result);
        break;
    }
  }
  
  sendMessage(text: string) {
    this.send({
      type: 'incomingChatMessage',
      content: text,
      timestamp: new Date().toISOString()
    });
  }
  
  private send(data: any) {
    if (this.ws?.readyState === WebSocket.OPEN) {
      this.ws.send(JSON.stringify(data));
    }
  }
  
  disconnect() {
    this.send({
      type: 'terminate',
      timestamp: new Date().toISOString()
    });
    this.ws?.close();
  }
  
  onMessage?: (text: string) => void;
}

Step 3: Send Messages

// Send message
chatConnection.sendMessage('Hello, agent!');

// Or directly via WebSocket
ws.send(JSON.stringify({
  type: 'incomingChatMessage',
  content: 'Hello, agent!',
  timestamp: new Date().toISOString()
}));

Step 4: Receive Messages

Message Types

Chat conversations receive several message types: Text Messages (text type):

{
  type: 'text',
  timestamp: '2025-01-20T10:00:00Z',
  content: {
    source: 'assistant' | 'user',
    text: 'Message content',
    name?: string | null,
    // For user messages:
    segmentId?: string,
    type?: 'potential' | 'final' | 'confident',
    startISOTimes?: string,
    endISOTimes?: string | null,
    // For assistant messages (voice calls):
    synthStartISOTimes?: string | null,  // TTS synthesis start
    synthEndISOTimes?: string | null,    // TTS synthesis end
    playStartISOTimes?: string | null,   // Audio playback start
    playEndISOTimes?: string | null      // Audio playback end
  }
}

Events (event type):

{
  type: 'event',
  name: 'connection' | 'opened' | 'closed',
  timestamp: '2025-01-20T10:00:00Z'
}

Conversation Result (conversationResult type):

{
  type: 'conversationResult',
  result: {
    // Conversation summary and metadata
  },
  timestamp: '2025-01-20T10:00:00Z'
}

Handling Messages

// Handle incoming WebSocket messages
ws.onmessage = (event) => {
  const message = JSON.parse(event.data);
  
  switch (message.type) {
    case 'text':
      const content = message.content;
      if (content.source === 'assistant') {
        // Agent message
        displayAgentMessage(content.text);
        addMessageToUI(content.text || '', 'agent');
      } else if (content.source === 'user') {
        // User message (echo of what you sent)
        displayUserMessage(content.text);
      }
      break;
      
    case 'toolCall':
      // Agent is calling a tool
      displayToolCall(message);
      break;
      
    case 'toolCallResult':
      // Tool execution result
      displayToolResult(message);
      break;
      
    case 'event':
      // Handle connection events
      if (message.name === 'connection') {
        console.log('Session ready');
      }
      break;
  }
};

Step 5: Complete Chat Example

Here’s a complete, production-ready chat implementation:

React
Vanilla JavaScript
Node.js

import React, { useState, useEffect, useRef } from 'react';

interface Message {
  id: string;
  text: string;
  sender: 'user' | 'agent';
  timestamp: Date;
}

export function ChatWidget() {
  const [messages, setMessages] = useState<Message[]>([]);
  const [input, setInput] = useState('');
  const [isConnected, setIsConnected] = useState(false);
  const wsRef = useRef<WebSocket | null>(null);
  const messagesEndRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    // Connect to WebSocket
    const ws = new WebSocket(
      'wss://blackbox.dasha.ai/api/v1/ws/webCall?token=YOUR_WEB_INTEGRATION_TOKEN'
    );
    wsRef.current = ws;

    ws.onopen = () => {
      setIsConnected(true);
      // Send initialization message
      ws.send(JSON.stringify({
        type: 'initialize',
        timestamp: new Date().toISOString(),
        request: {
          callType: 'chat',
          additionalData: {}
        }
      }));
    };

    ws.onmessage = (event) => {
      const message = JSON.parse(event.data);
      
      if (message.type === 'text' && message.content.source === 'assistant') {
        addMessage(message.content.text || '', 'agent');
      } else if (message.type === 'event' && message.name === 'connection') {
        setIsConnected(true);
      } else if (message.type === 'error') {
        console.error('Chat error:', message);
        addMessage('Sorry, an error occurred. Please try again.', 'agent');
      }
    };

    ws.onerror = (error) => {
      console.error('WebSocket error:', error);
      setIsConnected(false);
    };

    ws.onclose = () => {
      setIsConnected(false);
    };

    return () => {
      if (wsRef.current) {
        wsRef.current.close();
      }
    };
  }, []);

  const addMessage = (text: string, sender: 'user' | 'agent') => {
    setMessages(prev => [...prev, {
      id: `${Date.now()}-${Math.random()}`,
      text,
      sender,
      timestamp: new Date()
    }]);
  };

  const sendMessage = () => {
    if (!input.trim() || !wsRef.current || wsRef.current.readyState !== WebSocket.OPEN) return;

    const text = input.trim();
    addMessage(text, 'user');
    
    // Send message via WebSocket
    wsRef.current.send(JSON.stringify({
      type: 'incomingChatMessage',
      content: text,
      timestamp: new Date().toISOString()
    }));
    
    setInput('');
  };

  useEffect(() => {
    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' });
  }, [messages]);

  return (
    <div className="chat-widget">
      <div className="chat-header">
        <h3>Chat with Agent</h3>
        <div className={`status ${isConnected ? 'connected' : 'disconnected'}`}>
          {isConnected ? '● Connected' : '○ Disconnected'}
        </div>
      </div>

      <div className="chat-messages">
        {messages.map(msg => (
          <div key={msg.id} className={`message ${msg.sender}`}>
            <div className="message-content">{msg.text}</div>
            <div className="message-time">
              {msg.timestamp.toLocaleTimeString()}
            </div>
          </div>
        ))}
        <div ref={messagesEndRef} />
      </div>

      <div className="chat-input">
        <input
          type="text"
          value={input}
          onChange={(e) => setInput(e.target.value)}
          onKeyPress={(e) => {
            if (e.key === 'Enter' && !e.shiftKey) {
              e.preventDefault();
              sendMessage();
            }
          }}
          placeholder="Type a message..."
          disabled={!isConnected}
        />
        <button onClick={sendMessage} disabled={!isConnected || !input.trim()}>
          Send
        </button>
      </div>
    </div>
  );
}

<!DOCTYPE html>
<html>
<head>
  <title>Dasha BlackBox Chat</title>
  <style>
    .chat-container {
      max-width: 600px;
      margin: 0 auto;
      border: 1px solid #ddd;
      border-radius: 8px;
      overflow: hidden;
    }
    .chat-messages {
      height: 400px;
      overflow-y: auto;
      padding: 16px;
      background: #f5f5f5;
    }
    .message {
      margin-bottom: 12px;
      padding: 8px 12px;
      border-radius: 8px;
      max-width: 80%;
    }
    .message.user {
      background: #007bff;
      color: white;
      margin-left: auto;
    }
    .message.agent {
      background: white;
      border: 1px solid #ddd;
    }
    .chat-input {
      display: flex;
      padding: 16px;
      border-top: 1px solid #ddd;
    }
    .chat-input input {
      flex: 1;
      padding: 8px;
      border: 1px solid #ddd;
      border-radius: 4px;
    }
    .chat-input button {
      margin-left: 8px;
      padding: 8px 16px;
      background: #007bff;
      color: white;
      border: none;
      border-radius: 4px;
      cursor: pointer;
    }
  </style>
</head>
<body>
  <div class="chat-container">
    <div class="chat-messages" id="messages"></div>
    <div class="chat-input">
      <input type="text" id="input" placeholder="Type a message...">
      <button id="send">Send</button>
    </div>
  </div>

  <script type="module">
    const messagesDiv = document.getElementById('messages');
    const input = document.getElementById('input');
    const sendButton = document.getElementById('send');

    function addMessage(text, sender) {
      const messageDiv = document.createElement('div');
      messageDiv.className = `message ${sender}`;
      messageDiv.textContent = text;
      messagesDiv.appendChild(messageDiv);
      messagesDiv.scrollTop = messagesDiv.scrollHeight;
    }

    const ws = new WebSocket(
      'wss://blackbox.dasha.ai/api/v1/ws/webCall?token=YOUR_WEB_INTEGRATION_TOKEN'
    );

    ws.onopen = () => {
      ws.send(JSON.stringify({
        type: 'initialize',
        timestamp: new Date().toISOString(),
        request: {
          callType: 'chat',
          additionalData: {}
        }
      }));
    };

    ws.onmessage = (event) => {
      const message = JSON.parse(event.data);
      
      if (message.type === 'text' && message.content.source === 'assistant') {
        addMessage(message.content.text, 'agent');
      } else if (message.type === 'error') {
        addMessage('Error: ' + (message.data?.message || message.message || 'Unknown error'), 'agent');
      }
    };

    sendButton.addEventListener('click', () => {
      const text = input.value.trim();
      if (text && ws.readyState === WebSocket.OPEN) {
        addMessage(text, 'user');
        ws.send(JSON.stringify({
          type: 'incomingChatMessage',
          content: text,
          timestamp: new Date().toISOString()
        }));
        input.value = '';
      }
    });

    input.addEventListener('keypress', (e) => {
      if (e.key === 'Enter') {
        sendButton.click();
      }
    });
  </script>
</body>
</html>

const WebSocket = require('ws');
const readline = require('readline');

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

const ws = new WebSocket(
  'wss://blackbox.dasha.ai/api/v1/ws/webCall?token=YOUR_WEB_INTEGRATION_TOKEN'
);

let isConnected = false;

ws.on('open', () => {
  isConnected = true;
  console.log('[Status] Connected');
  
  // Send initialization message
  ws.send(JSON.stringify({
    type: 'initialize',
    timestamp: new Date().toISOString(),
    request: {
      callType: 'chat',
      additionalData: {}
    }
  }));
  
  console.log('Chat started! Type your messages (Ctrl+C to exit)\n');
  rl.setPrompt('You: ');
  rl.prompt();
});

ws.on('message', (data) => {
  const message = JSON.parse(data.toString());
  
  if (message.type === 'text' && message.content.source === 'assistant') {
    console.log(`\n[Agent] ${message.content.text}\n`);
    rl.prompt();
  } else if (message.type === 'event' && message.name === 'connection') {
    console.log('[Status] Session ready');
  } else if (message.type === 'error') {
    console.error('[Error]', message);
  }
});

ws.on('error', (error) => {
  console.error('[Error]', error);
});

ws.on('close', () => {
  isConnected = false;
  console.log('[Status] Disconnected');
});

rl.on('line', (input) => {
  const text = input.trim();
  if (text && isConnected && ws.readyState === WebSocket.OPEN) {
    ws.send(JSON.stringify({
      type: 'incomingChatMessage',
      content: text,
      timestamp: new Date().toISOString()
    }));
  }
  rl.prompt();
});

rl.on('close', () => {
  if (ws.readyState === WebSocket.OPEN) {
    ws.send(JSON.stringify({
      type: 'terminate',
      timestamp: new Date().toISOString()
    }));
    ws.close();
  }
  process.exit(0);
});

Step 6: Handle Connection States

Monitor and handle connection states for better UX:

let connectionStatus: 'connecting' | 'open' | 'closed' | 'error' = 'closed';

const ws = new WebSocket('wss://blackbox.dasha.ai/api/v1/ws/webCall?token=YOUR_WEB_INTEGRATION_TOKEN');

ws.onopen = () => {
  connectionStatus = 'open';
  showStatus('Connected');
  enableInput();
  hideRetryButton();
};

ws.onclose = () => {
  connectionStatus = 'closed';
  showStatus('Disconnected');
  disableInput();
  showRetryButton();
};

ws.onerror = () => {
  connectionStatus = 'error';
  showStatus('Connection error');
  disableInput();
  showRetryButton();
};

// Track connecting state
connectionStatus = 'connecting';
showStatus('Connecting...');
disableInput();

Step 7: Handle Errors

Implement robust error handling:

ws.onmessage = (event) => {
  const message = JSON.parse(event.data);
  
  if (message.type === 'error') {
    // Parse error message
    const errorMessage = message.data?.message || message.message || 'An unexpected error occurred';
    console.error('Error details:', message);
    
    // Show user-friendly error message
    showErrorMessage(errorMessage);
    
    // Optionally retry connection
    if (shouldRetry(message)) {
      setTimeout(() => {
        ws.close();
        connect(); // Reconnect function
      }, 3000);
    }
  }
};

ws.onerror = (error) => {
  console.error('WebSocket error:', error);
  showErrorMessage('Connection error occurred');
};

Step 8: Graceful Disconnection

Properly terminate conversations:

let conversationResult: any = null;

// Listen for conversation result
ws.onmessage = (event) => {
  const message = JSON.parse(event.data);
  if (message.type === 'conversationResult') {
    conversationResult = message.result;
  }
};

// Option 1: Immediate disconnect
ws.close();

// Option 2: Graceful end (wait for conversation result)
function gracefulEnd(timeoutMs: number = 3000): Promise<'result' | 'timeout' | 'error'> {
  return new Promise((resolve) => {
    // Send terminate message
    ws.send(JSON.stringify({
      type: 'terminate',
      timestamp: new Date().toISOString()
    }));
    
    // Wait for conversation result
    const timeout = setTimeout(() => {
      resolve('timeout');
      ws.close();
    }, timeoutMs);
    
    const checkResult = () => {
      if (conversationResult) {
        clearTimeout(timeout);
        resolve('result');
        ws.close();
      }
    };
    
    ws.onmessage = (event) => {
      const message = JSON.parse(event.data);
      if (message.type === 'conversationResult') {
        conversationResult = message.result;
        checkResult();
      }
    };
  });
}

// Usage
const result = await gracefulEnd(3000);
if (result === 'result') {
  console.log('Conversation completed:', conversationResult);
} else if (result === 'timeout') {
  console.log('Timeout waiting for result');
} else {
  console.log('Error during graceful end');
}

Advanced Features

Message History

Maintain and access full conversation history:

const messageHistory: any[] = [];

ws.onmessage = (event) => {
  const message = JSON.parse(event.data);
  messageHistory.push(message);
  
  // Filter by type
  const textMessages = messageHistory.filter(msg => msg.type === 'text');
  const toolCalls = messageHistory.filter(msg => msg.type === 'toolCall');
  
  // Access conversation result
  const result = messageHistory.find(msg => msg.type === 'conversationResult')?.result;
};

Streaming Responses

Handle streaming/partial messages:

ws.onmessage = (event) => {
  const message = JSON.parse(event.data);
  
  if (message.type === 'text') {
    const content = message.content;
    
    // Handle partial messages
    if (content.type === 'potential') {
      // Agent is still thinking (streaming)
      updatePartialMessage(content.text);
    } else if (content.type === 'final' || content.type === 'confident') {
      // Final message
      finalizeMessage(content.text);
    }
  }
};

Custom Data

Pass custom context to agent:

ws.onopen = () => {
  ws.send(JSON.stringify({
    type: 'initialize',
    timestamp: new Date().toISOString(),
    request: {
      callType: 'chat',
      additionalData: {
        userId: 'user123',
        productId: 'prod456',
        sessionData: {
          page: '/products',
          referrer: 'google.com'
        }
      }
    }
  }));
};

Troubleshooting

Connection Fails

Symptoms: Connection status stays at connecting or goes to error Solutions:

Verify token is valid and not expired
Check server URL is correct
Ensure HTTPS/WSS is used (not HTTP/WS)
Check network/firewall allows WebSocket connections
Verify agent is enabled and configured

Messages Not Received

Symptoms: Messages sent but no response from agent Solutions:

Check WebSocket message handler is registered
Verify WebSocket readyState is OPEN before sending
Check browser console for WebSocket errors
Ensure agent has valid LLM configuration
Verify AllowWebChat feature is enabled

Connection Drops

Symptoms: Connection closes unexpectedly Solutions:

Implement reconnection logic
Check for network interruptions
Monitor WebSocket connection state (readyState)
Handle WebSocket onclose and onerror events
Send terminate message before closing connection

Next Steps

Voice Call Implementation - Add WebRTC voice calls
Tool Execution - Handle agent tool calls
Message Reference - Complete message documentation

Introduction

Build

Deploy

Monitor

Webhooks & Events

Advanced

WebSockets

Chat Implementation

Chat Implementation

Prerequisites

Step 1: Install Dependencies

Step 2: Create Connection

Step 3: Send Messages

Step 4: Receive Messages

Message Types

Handling Messages

Step 5: Complete Chat Example

Step 6: Handle Connection States

Step 7: Handle Errors

Step 8: Graceful Disconnection

Advanced Features

Message History

Streaming Responses

Custom Data

Troubleshooting

Connection Fails

Messages Not Received

Connection Drops

Next Steps

Introduction

Build

Deploy

Monitor

Webhooks & Events

Advanced

WebSockets

​Chat Implementation

​Prerequisites

​Step 1: Install Dependencies

​Step 2: Create Connection

​Step 3: Send Messages

​Step 4: Receive Messages

​Message Types

​Handling Messages

​Step 5: Complete Chat Example

​Step 6: Handle Connection States

​Step 7: Handle Errors

​Step 8: Graceful Disconnection

​Advanced Features

​Message History

​Streaming Responses

​Custom Data

​Troubleshooting

​Connection Fails

​Messages Not Received

​Connection Drops

​Next Steps

Chat Implementation

Prerequisites

Step 1: Install Dependencies

Step 2: Create Connection

Step 3: Send Messages

Step 4: Receive Messages

Message Types

Handling Messages

Step 5: Complete Chat Example

Step 6: Handle Connection States

Step 7: Handle Errors

Step 8: Graceful Disconnection

Advanced Features

Message History

Streaming Responses

Custom Data

Troubleshooting

Connection Fails

Messages Not Received

Connection Drops

Next Steps