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Implementing Auto Refresh for Real Time Weather Data in a Flask Application

How Auto-Refresh is Implemented

  1. Tracking the Current City: The variable currentCity is used to store the city for which weather data is fetched. Initially, it is empty, but when a user enters a city name in the search box and clicks the search button, this variable is populated with the city name.
let currentCity = ""; // Track current city for auto-refresh
  1. Fetching Weather Data: The checkWeather(city) function is responsible for fetching the weather data from the Flask API using the fetch() function. The API endpoint is /weather, and the city name is passed as a query parameter.
const response = await fetch(`${apiUrl}?city=${city}`);

After receiving the data, the UI is updated with the city name, temperature, humidity, wind speed, and appropriate weather icon based on the condition (e.g., Clear, Cloudy, Rain, etc.).

  1. Auto-Refresh Mechanism: The setInterval() function is used to refresh the weather data every 10 minutes (600,000 milliseconds). This is done by calling the checkWeather() function with the currentCity as the argument. 
setInterval(() => {
    if (currentCity) {
        checkWeather(currentCity);
    }
}, 600000);

  • How It Works:

    • The setInterval() method repeatedly calls the checkWeather(currentCity) function every 10 minutes.
    • The checkWeather function fetches the latest weather data for the stored city (currentCity) and updates the UI accordingly.
    • The interval continues as long as the currentCity is set (i.e., the user has searched for a city).

  • Why Auto-Refresh is Useful:

  • Real-Time Updates: The auto-refresh feature ensures that users always have the latest weather data without needing to manually refresh the page or re-enter the city.
  • User Convenience: This is especially useful for users who want up-to-date information without any action required on their part.

  • Weather Monitoring: In the case of weather monitoring applications, it ensures that the weather data remains current, which can be crucial for planning activities or responding to changing conditions.

  • UI Updates: Each time the data is fetched from the API, the UI elements that display the weather data (e.g., temperature, humidity, wind speed, and weather icon) are updated to reflect the most recent information.

How It Works in the Code:

  • When the user searches for a city and hits the search button, the city name is passed to the checkWeather(city) function, which fetches the weather data from the Flask backend.
  • The auto-refresh mechanism ensures that after every 10 minutes, the app automatically fetches the weather data for the same city without any user interaction.

Summary

The auto-refresh feature implemented here fetches updated weather data from the Flask API every 10 minutes for the currently selected city. This allows users to always view the latest weather information without manual intervention. The use of setInterval() ensures that the data is regularly updated and the UI remains current.