Weather and Air Quality Fetcher

Table of Contents

1. Introduction
2. Features
3. Prerequisites
4. Installation
5. Usage
   1. Command-Line Arguments
   2. Examples
6. Sample Output
7. Script Details
   1. Function Definitions
   2. Fetching Weather Data
   3. Fetching AQI Data
   4. Displaying Weather Details
8. Error Handling
9. API Information
10. License
11. Acknowledgments

Introduction

I really put some work into this project and here is my finalised code, feeling good after making all the stuff work and seeing it in action. The Weather and Air Quality Fetcher script provides a comprehensive weather report for a specified city. It fetches weather data from both wttr.in and OpenWeatherMap, including details such as temperature, weather conditions, sunrise and sunset times, and the Air Quality Index (AQI). The script then displays this information in a user-friendly format.

Features

• Fetches weather summary from wttr.in.
• Fetches detailed weather data from OpenWeatherMap.
• Fetches and displays the Air Quality Index (AQI) and its descriptive level.
• Displays sunrise and sunset times in a human-readable format.
• Error handling for invalid city names.

Prerequisites

• jq: A lightweight and flexible command-line JSON processor.
• curl: A command-line tool for transferring data with URLs.

Ensure both jq and curl are installed on your system.

Installation

To install jq and curl, you can use the following commands based on your operating system:

For Ubuntu/Debian:

sudo apt-get update
sudo apt-get install jq curl

For CentOS/RHEL:

sudo yum install jq curl

For macOS:

brew install jq curl

Usage

Command-Line Arguments

./weather_script.sh <city_name>

Examples

./weather_script.sh Delhi
./weather_script.sh Kerala

Sample Output

Fetching weather details for Delhi.....
========================================
          WEATHER REPORT
========================================
Delhi: 🌞 +30°C
========================================
        DETAILED WEATHER REPORT
{
  "coord": { "lon": 77.22, "lat": 28.67 },
  "weather": [
    { "main": "Clear", "description": "clear sky" }
  ],
  "main": { "temp": 30.0, "pressure": 1012, "humidity": 40 },
  "visibility": 10000,
  "wind": { "speed": 5.7, "deg": 320 },
  "clouds": { "all": 0 },
  "dt": 1618914195,
  "sys": {
    "type": 1,
    "id": 9052,
    "country": "IN",
    "sunrise": 1618872354,
    "sunset": 1618917224
  },
  "timezone": 19800,
  "id": 1273294,
  "name": "Delhi",
  "cod": 200
}
========================================
Sunrise: Sat Apr 24 06:32:34 UTC 2021
Sunset: Sat Apr 24 19:27:04 UTC 2021
Air Quality Index (AQI): 3 (Moderate)
========================================
For more details, visit: https://wttr.in/Delhi

Script Details

Function Definitions

• if_error: Displays usage information and example command.

  if_error(){
      echo "Usage: $0 <city_name>"
      echo "Example: $0 Kerala"
  }

Fetching Weather Data

• Fetches weather summary from wttr.in.

  WEATHER=$(curl -s "https://wttr.in/${city}?format=3")

• Fetches detailed weather data from OpenWeatherMap using the provided API key.

  CURRENT_WEATHER=$(curl -s --max-time 10 "http://api.openweathermap.org/data/2.5/weather?q=${city}&appid=${api_key}&units=metric")

• Checks for valid responses and handles errors accordingly.

  if [[ "$(echo "$CURRENT_WEATHER" | jq -r '.cod')" == "404" ]]; then
      echo "Error: Unable to fetch weather details for '$city' from OpenWeatherMap. Check the city name"
      exit 1
  fi
  
  if [[ "$WEATHER" == *"Unknown location"* ]]; then
      echo "Error: Unable to fetch weather details for '$city'. Check the city name"
      exit 1
  fi

Fetching AQI Data

• Extracts latitude and longitude from the weather data.

  lat=$(echo "$CURRENT_WEATHER" | jq -r '.coord.lat')
  lon=$(echo "$CURRENT_WEATHER" | jq -r '.coord.lon')

• Fetches AQI data from OpenWeatherMap.

  AQI_DATA=$(curl -s --max-time 10 "http://api.openweathermap.org/data/2.5/air_pollution?lat=${lat}&lon=${lon}&appid=${api_key}")

• Extracts the AQI value and maps it to a descriptive level using a case statement.

  AQI=$(echo "$AQI_DATA" | jq -r '.list[0].main.aqi')
  
  case $AQI in
      1) AQI_LEVEL="Good";;
      2) AQI_LEVEL="Fair";;
      3) AQI_LEVEL="Moderate";;
      4) AQI_LEVEL="Poor";;
      5) AQI_LEVEL="Very Poor";;
      *) AQI_LEVEL="Unknown";;
  esac

Displaying Weather Details

• Extracts and converts sunrise and sunset times to a human-readable format.

  SUNRISE=$(echo "$CURRENT_WEATHER" | jq -r '.sys.sunrise')
  SUNSET=$(echo "$CURRENT_WEATHER" | jq -r '.sys.sunset')
  SUNRISE_TIME=$(date -d @$SUNRISE)
  SUNSET_TIME=$(date -d @$SUNSET)

• Displays the fetched weather summary.

  echo "========================================"
  echo "          WEATHER REPORT"
  echo "========================================"
  echo "$WEATHER"
  echo "========================================"

• Displays detailed weather information, including temperature, weather conditions, sunrise/sunset times, and AQI.

  echo "        DETAILED WEATHER REPORT"
  echo "$CURRENT_WEATHER"
  echo "========================================"
  echo "Sunrise: $SUNRISE_TIME"
  echo "Sunset: $SUNSET_TIME"
  echo "Air Quality Index (AQI): $AQI ($AQI_LEVEL)"
  echo "========================================"

Error Handling

The script checks for the following errors:

• City name not provided.

  if [ -z "$city" ]; then
      echo "Error: City name not provided."
      if_error
      exit 1
  fi

• Invalid city name resulting in a 404 response from OpenWeatherMap.

  if [[ "$(echo "$CURRENT_WEATHER" | jq -r '.cod')" == "404" ]]; then
      echo "Error: Unable to fetch weather details for '$city' from OpenWeatherMap. Check the city name"
      exit 1
  fi

• Unknown location response from wttr.in.

  if [[ "$WEATHER" == *"Unknown location"* ]]; then
      echo "Error: Unable to fetch weather details for '$city'. Check the city name"
      exit 1
  fi

API Information

• OpenWeatherMap API: Provides detailed weather and air quality data. You need an API key to access this service. Sign up at OpenWeatherMap to get your API key.
• wttr.in: A simple weather service that provides weather reports for a given location.

License

This project is licensed under the MIT License. See the LICENSE file for details

Acknowledgments

• wttr.in for providing a simple weather report.
• OpenWeatherMap for detailed weather and AQI data.

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