http-response

Overview

The http-response node sends an HTTP response back to the client that made the original request. It must be paired with an http-in or http-webhook node. The response body is taken from msg.payload, and the status code, headers, and cookies can all be configured statically or set dynamically via message properties.

Properties

Dynamic Message Properties

Set these properties on the incoming message to control the response dynamically:

Example: REST API Response with JSON Data

Return sensor readings as a JSON API response. The http-in node receives the request, a function node builds the response data, and http-response sends it back.

// Function node before http-response:
const readings = flow.get('sensorReadings') || [];
msg.payload = {
  status: "ok",
  count: readings.length,
  data: readings,
  timestamp: new Date().toISOString()
};
msg.headers = {
  "Content-Type": "application/json",
  "Cache-Control": "no-cache"
};
msg.statusCode = 200;
return msg;

// http-response node sends:
// HTTP/1.1 200 OK
// Content-Type: application/json
// Cache-Control: no-cache
//
// {
//   "status": "ok",
//   "count": 5,
//   "data": [...],
//   "timestamp": "2024-01-15T14:30:00Z"
// }

Example: Custom Error Responses

Return different HTTP error codes based on validation results. Use a switch node to route success and error paths to separate http-response nodes or set msg.statusCode dynamically.

// Function node with error handling:
const data = msg.payload;

// Validate required fields
if (!data || !data.sensor_id) {
  msg.statusCode = 400;
  msg.payload = {
    error: "Bad Request",
    message: "sensor_id is required"
  };
  return msg;
}

// Check if sensor exists
const sensor = flow.get('sensors.' + data.sensor_id);
if (!sensor) {
  msg.statusCode = 404;
  msg.payload = {
    error: "Not Found",
    message: "Sensor " + data.sensor_id + " not found"
  };
  return msg;
}

// Check authorization
if (msg.req.headers['x-api-key'] !== env.get('API_KEY')) {
  msg.statusCode = 401;
  msg.payload = {
    error: "Unauthorized",
    message: "Invalid API key"
  };
  return msg;
}

// Success
msg.statusCode = 200;
msg.payload = { status: "ok", sensor: sensor };
return msg;

Common Status Codes

Common Use Cases