The Python Flask code snippet you provided sets up a simple web server capable of receiving POST requests containing JSON data, specifically for temperature and humidity values. Here's a detailed breakdown of its components and functionality:

Flask Application Overview

• Application Setup: The application is built using Flask, a lightweight WSGI web application framework in Python. It is designed to be quick and easy to get started with, making it an excellent choice for simple web APIs.

Route Description

• Endpoint: '/data'

  • This endpoint listens for POST requests. It is intended to receive JSON data that includes temperature and humidity readings.

• Function: sensor_data()

  • This function processes incoming POST requests to the /data endpoint.

Request Handling

• JSON Data Retrieval:

  • data = request.get_json() extracts JSON data from the incoming POST request. Flask automatically handles the parsing of JSON data if the Content-Type header of the request is set to application/json.

• Data Processing:

  • The temperature and humidity values are extracted from the JSON data using data.get('temperature') and data.get('humidity'). The .get() method is used for safe access, which returns None if the specified key does not exist, rather than throwing an error.
  • These values are then printed to the console with the format: "Received temperature: {t}°C, humidity: {h}%". This logging is helpful for debugging and monitoring the data received by the server.

Response Construction

• Response JSON Object:

  • A response JSON object is constructed containing a message stating "Data received successfully", along with the received temperature and humidity values. This response confirms to the client that the data was received and processed.

• Response Return:

  • return jsonify(res), 200 sends the response back to the client. The jsonify function from Flask converts the Python dictionary into a JSON response. The 200 HTTP status code indicates that the request has been processed successfully.

Server Execution

• Running the Server:
  • if __name__ == '__main__': app.run(host='0.0.0.0', port=5000)
  • This condition ensures that the Flask server runs directly when the script is executed, not when imported as a module.
  • host='0.0.0.0' tells the server to be accessible externally, not just locally. It listens on all network interfaces.
  • port=5000 specifies that the server will be accessible on TCP port 5000, which is the default port for Flask development servers.