Final set of changes for realtime support.

Cargo.toml

@@ -8,10 +8,12 @@ host = "x86_64-unknown-linux-gnu"
 chrono = "0.4"
 csv = "1.4"
 gtfs-structures = "0.47"
+gtfs-realtime = "0.2"
 log = "0.4"
 reqwest = { version = "0.11", features = ["blocking"] }
 sdl3 = {version = "0.17", features = ["ttf"]}
 serde = { version = "1.0", features = ["derive"]}
+serde_json = "1.0"
 time-format = "1.2"
 yaml_serde = "0.10"
 zip = "8.3"

src/gtfs/mod.rs

@@ -2,15 +2,16 @@ mod arrival;
 mod loader;
 mod utils;
 mod refresher;
+mod realtime;
 pub mod structs;
 use chrono::{DateTime, Local, Timelike};
-use log::{debug, trace};
+use log::{debug, trace, warn};
 use std::{collections::{HashMap, HashSet}, fs::File };
-use gtfs_structures::{Exception, RawTrip};
+use gtfs_structures::{ContinuousPickupDropOff::ArrangeByPhone, Exception, RawTrip};
 use crate::gtfs::{loader::load_gtfs, structs::{Arrival, Gtfs, Preferences, Error}};
 
 
-impl Gtfs {
+impl Gtfs<'_> {
 
     pub fn get_next_arrivals_for(&self, target_datetime: &DateTime<Local>) -> Option<Vec<Arrival<'_>>> {
         let naive_target = target_datetime.naive_local();
@@ -81,9 +82,18 @@ impl Gtfs {
                 }
             }
         }
+
         arrivals.sort();
+
         debug!("Found {} arrivals", arrivals.len());
 
+        // Update real-time deltas
+
+        let realtime_result = self.realtime_update(&mut arrivals);
+        if realtime_result.is_err() {
+            warn!("Unable to update realtime arrivals: {:#?}", realtime_result.err().unwrap()._message)
+        }
+
         return Some(arrivals);
     }
         
@@ -98,6 +108,7 @@ impl Gtfs {
         let mut zip_reader = zip::ZipArchive::new(zip_file)?;
 
         let mut gtfs: Gtfs = Gtfs {
+            preferences: prefs,
             agencies: Vec::new(),
             calendar: HashMap::new(),
             calendar_dates: HashMap::new(),

src/gtfs/realtime.rs

@@ -0,0 +1,77 @@
+use log::debug;
+/***
+ * Implementation of GTFS-R polling 
+  */
+use reqwest::{StatusCode, blocking::Client};
+use std::{collections::HashMap, time::Duration};
+
+use crate::gtfs::{self, structs::{Arrival, Error, Gtfs}};
+
+impl Gtfs<'_> {
+    pub(crate) fn realtime_update (&self, arrivals: &mut Vec<Arrival<'_>>) -> Result<(), gtfs::structs::Error>{
+
+        // Poll GTFS-R API
+        let client = Client::builder()
+            .timeout(Duration::from_secs(10))
+            .connect_timeout(Duration::from_secs(5))
+            .build()?;
+        
+        let response = client
+            .get(&self.preferences.realtime_url)
+            .header("x-api-key", &self.preferences.realtime_api_key)
+            .send()?;
+
+        if response.status() != StatusCode::OK {
+            return Err(Error {
+                _message : format!("HTTP Respomse: {:#?}. Payload: \n{:#?}\n", response.status(), response.text().unwrap())
+            })
+        }
+
+        // Parse response
+        let realtime_info: gtfs_realtime::FeedMessage  
+            = serde_json::from_reader(response)?;
+
+
+        // Build a map of (trip, stop) -> Arrival for faster lookup
+        let mut lookup: HashMap<(String, String), usize> = HashMap::new();
+        let num_arrivals = arrivals.len();
+        for i in 0..num_arrivals {
+            let arrival = arrivals.get(i).unwrap();
+            lookup.insert((arrival.trip.id.clone(), arrival.stop.id.clone()), i);
+        }
+
+        // Match deltas to existing arrivals
+        for entity  in realtime_info.entity {
+            if entity.trip_update.is_some() && entity.stop.is_some() {
+                let trip_update = entity.trip_update.unwrap();
+                
+                // Look up the entry in arrivals for the current
+                for stop_update in trip_update.stop_time_update {
+                    if stop_update.stop_id.is_none() {
+                        continue;
+                    } 
+                    let trip_id = trip_update.trip.trip_id.clone().unwrap();
+                    let stop_id = stop_update.stop_id.unwrap();
+                    let key = (trip_id, stop_id); 
+                    if lookup.contains_key(&key) {
+                       
+                        // Update the arrival time
+                        let arrival_index = lookup.get(&key);
+                        let arrival: &mut Arrival<'_> = arrivals.get_mut(*arrival_index.unwrap()).unwrap();
+                        if let Some(update) = stop_update.departure.or(stop_update.arrival) {
+                            let new_time = (((arrival.departure_time as i64) 
+                                                        + (update.delay.unwrap_or(0) as i64))) as u32;
+                            debug!("Updated arrival time of {:#?} by {}s", &key, update.delay.unwrap());
+                            arrival.departure_time = new_time;
+                        }
+                    }
+                }
+            }
+        }
+
+        return Ok(());
+        }
+    }
+
+
+

src/gtfs/structs.rs

@@ -28,6 +28,12 @@ impl From<ZipError> for Error {
     }
 }
 
+impl From<serde_json::Error> for Error {
+    fn from(value: serde_json::Error) -> Self {
+        return Error { _message: value.to_string() }
+    }
+}
+
 
 // This is to store the preferences for the GTFS(-R) side of the code.
 #[derive(Debug, PartialEq, Serialize, Deserialize)]
@@ -74,7 +80,10 @@ impl Preferences {
 
 // The main GTFS struct. This is similar to (but not exactly) gtfs-structures::Gtfs because we don't need everything
 #[derive(Debug)]
-pub struct Gtfs {
+pub struct Gtfs<'a> {
+    /// A copy of the preferences struct
+    pub(crate) preferences: &'a Preferences,
+
     /// All agencies. They can not be read by `agency_id`, as it is not a required field
     pub(crate) agencies: Vec<Agency>,
     /// All Calendar by `service_id`