133 lines
2.8 KiB
Go
133 lines
2.8 KiB
Go
package main
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import (
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"encoding/xml"
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"fmt"
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"io"
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"log"
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"net/http"
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"strconv"
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"time"
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)
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const (
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baseURL = "https://api.met.no/weatherapi"
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userAgent = "liustatus/1.0"
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// Prague coordinates.
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lat = 50.08804
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lon = 14.42076
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altitude = 202
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)
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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type Weatherdata struct {
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XMLName xml.Name `xml:"weatherdata"`
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Product Product `xml:"product"`
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}
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type Product struct {
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Times []Time `xml:"time"`
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}
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type Time struct {
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From string `xml:"from,attr"`
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To string `xml:"to,attr"`
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Location Location `xml:"location"`
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}
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type Location struct {
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Temperature *Temperature `xml:"temperature"`
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}
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type Temperature struct {
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Unit string `xml:"unit,attr"`
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Value string `xml:"value,attr"`
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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// WeatherFetcher handles weather data retrieval.
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type WeatherFetcher struct {
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client *http.Client
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}
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// NewWeatherFetcher creates a new weather fetcher instance.
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func NewWeatherFetcher() *WeatherFetcher {
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return &WeatherFetcher{
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client: &http.Client{Timeout: 30 * time.Second},
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}
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}
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// fetchWeather retrieves the current temperature from the API.
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func (w *WeatherFetcher) fetchWeather() (string, error) {
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url := fmt.Sprintf(
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"%s/locationforecast/2.0/classic?lat=%.5f&lon=%.5f&altitude=%d",
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baseURL, lat, lon, altitude)
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req, err := http.NewRequest("GET", url, nil)
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if err != nil {
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return "", err
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}
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req.Header.Set("User-Agent", userAgent)
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resp, err := w.client.Do(req)
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if err != nil {
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return "", err
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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return "", fmt.Errorf("API returned status %d", resp.StatusCode)
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}
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body, err := io.ReadAll(resp.Body)
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if err != nil {
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return "", err
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}
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var weatherData Weatherdata
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if err := xml.Unmarshal(body, &weatherData); err != nil {
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return "", err
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}
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now := time.Now().UTC()
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for _, t := range weatherData.Product.Times {
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toTime, err := time.Parse("2006-01-02T15:04:05Z", t.To)
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if err != nil || toTime.Before(now) {
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continue
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}
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if t.Location.Temperature != nil {
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temp, err := strconv.ParseFloat(t.Location.Temperature.Value, 64)
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if err != nil {
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continue
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}
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return fmt.Sprintf("%dﾟ", int(temp)), nil
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}
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}
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return "", fmt.Errorf("no usable temperature data found")
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}
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// update fetches new weather data and returns it.
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func (w *WeatherFetcher) update() string {
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temp, err := w.fetchWeather()
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if err != nil {
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log.Printf("Error fetching weather: %v", err)
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}
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return temp
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}
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// Run runs as a goroutine to periodically fetch weather data.
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func (w *WeatherFetcher) Run(interval time.Duration, output chan<- string) {
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ticker := time.NewTicker(interval)
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defer ticker.Stop()
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output <- w.update()
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for range ticker.C {
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output <- w.update()
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}
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}
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