forked from paul/sinoptik
120 lines
3.8 KiB
Rust
120 lines
3.8 KiB
Rust
//! The Buienradar data provider.
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//!
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//! For more information about Buienradar, see: <https://www.buienradar.nl/overbuienradar/contact>
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//! and <https://www.buienradar.nl/overbuienradar/gratis-weerdata>.
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use cached::proc_macro::cached;
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use chrono::offset::TimeZone;
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use chrono::serde::ts_seconds;
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use chrono::{DateTime, Local, NaiveTime, ParseError, Utc};
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use chrono_tz::Europe;
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use csv::ReaderBuilder;
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use reqwest::Url;
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use rocket::serde::{Deserialize, Serialize};
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use crate::position::Position;
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use crate::Metric;
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/// The base URL for the Buienradar API.
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const BUIENRADAR_BASE_URL: &str = "https://gpsgadget.buienradar.nl/data/raintext";
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/// A row in the precipitation text output.
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///
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/// This is an intermediate type used to represent rows of the output.
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#[derive(Debug, Deserialize)]
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#[serde(crate = "rocket::serde")]
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struct Row {
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/// The precipitation value in the range `0..=255`.
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value: u16,
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/// The time in the `HH:MM` format.
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time: String,
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}
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/// The Buienradar API precipitation data item.
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#[derive(Clone, Debug, Deserialize, Serialize)]
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#[serde(crate = "rocket::serde", try_from = "Row")]
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pub(crate) struct Item {
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/// The time(stamp) of the forecast.
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#[serde(serialize_with = "ts_seconds::serialize")]
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time: DateTime<Utc>,
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/// The forecasted value.
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///
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/// Its unit is mm/h.
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value: f32,
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}
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impl TryFrom<Row> for Item {
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type Error = ParseError;
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fn try_from(row: Row) -> Result<Self, Self::Error> {
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let time = parse_time(&row.time)?;
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let value = convert_value(row.value);
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Ok(Item { time, value })
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}
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}
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/// Parses a time string to date/time in the UTC time zone.
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///
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/// The provided time has the format `HH:MM` and is considered to be in the Europe/Amsterdam
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/// time zone.
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fn parse_time(t: &str) -> Result<DateTime<Utc>, ParseError> {
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// First, get the naive time.
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let ntime = NaiveTime::parse_from_str(t, "%H:%M")?;
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// FIXME: This might actually be the day before when started on a machine that
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// doesn't run in the Europe/Amsterdam time zone.
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let ndtime = Local::today().naive_local().and_time(ntime);
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// Then, interpret the naive date/time in the Europe/Amsterdam time zone and convert it to the
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// UTC time zone.
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let ldtime = Europe::Amsterdam.from_local_datetime(&ndtime).unwrap();
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let dtime = ldtime.with_timezone(&Utc);
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Ok(dtime)
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}
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/// Converts a precipitation value into an precipitation intensity value in mm/h.
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///
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/// For the conversion formula, see: <https://www.buienradar.nl/overbuienradar/gratis-weerdata>.
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fn convert_value(v: u16) -> f32 {
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let base: f32 = 10.0;
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let value = base.powf((v as f32 - 109.0) / 32.0);
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(value * 10.0).round() / 10.0
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}
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/// Retrieves the Buienradar forecasted precipitation items for the provided position.
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///
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/// It only supports the following metric:
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/// * [`Metric::Precipitation`]
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///
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/// Returns [`None`] if retrieval or deserialization fails, or if the metric is not supported by
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/// this provider.
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///
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/// If the result is [`Some`] it will be cached for 5 minutes for the the given position and
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/// metric.
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#[cached(time = 300, option = true)]
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pub(crate) async fn get(position: Position, metric: Metric) -> Option<Vec<Item>> {
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if metric != Metric::Precipitation {
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return None;
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}
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let mut url = Url::parse(BUIENRADAR_BASE_URL).unwrap();
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url.query_pairs_mut()
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.append_pair("lat", &position.lat_as_str(2))
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.append_pair("lon", &position.lon_as_str(2));
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println!("▶️ Retrieving Buienradar data from: {url}");
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let response = reqwest::get(url).await.ok()?;
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let output = match response.error_for_status() {
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Ok(res) => res.text().await.ok()?,
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Err(_err) => return None,
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};
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let mut rdr = ReaderBuilder::new()
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.has_headers(false)
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.delimiter(b'|')
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.from_reader(output.as_bytes());
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rdr.deserialize().collect::<Result<_, _>>().ok()
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}
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