Add HTTP server to export arrivals data.

arrivals_server.py

@@ -0,0 +1,38 @@
+import jsonpickle
+import threading
+import time
+
+from http.server import BaseHTTPRequestHandler, HTTPServer
+
+PORT=8080
+
+class ArrivalsServer:
+    def __init__(self, get_arrivals):
+      global _get_arrivals
+      _get_arrivals = get_arrivals
+
+    class Server(BaseHTTPRequestHandler):
+        def do_GET(self):
+            request_path = self.path
+            arrivals = _get_arrivals()
+
+            print("Request: ", request_path)
+
+            self.send_response(200)
+            self.send_header("Content-type", "application/json")
+            self.end_headers()
+
+            ts = time.time_ns()
+            data = jsonpickle.encode(arrivals)
+
+            self.wfile.write(f'{{ "timestamp": {ts}, "data": {data}}}'.encode("utf-8"))
+        
+        do_POST = do_GET
+        do_PUT = do_GET
+        do_DELETE = do_GET
+
+    def start(self) -> None:
+        print('HTTP server listening on Port %s' % PORT)
+        server = HTTPServer(('', PORT), self.Server)
+        _thread = threading.Thread(target = server.serve_forever)
+        _thread.start()

config.py

@@ -27,6 +27,10 @@ class Config:
     def update_interval_seconds(self) -> int:
         return self.config.get("update-interval-seconds")
 
+    @property
+    def http_server(self) -> bool:
+        return self.config.get("http-server")
+
     @property
     def stop_codes(self) -> list[str]:
         return [str(s["stop_id"]) for s in self.config.get("stops")]

config.yaml

@@ -12,6 +12,9 @@ gtfs-r-api_key: "API KEY GOES HERE"
 # It must be strictly larger than 60 because the GTFS-R API will throttle us otherwise
 update-interval-seconds: 62
 
+# Start a HTTP server emitting the current data as JSON or HTTP.
+http-server: false
+
 stops: [
   {
     # Route 15A

main.py

@@ -11,6 +11,7 @@ from time import sleep
 import queue
 from arrival_times import ArrivalTime
 from gtfs_client import GTFSClient
+from arrivals_server import ArrivalsServer
 
 # Constants
 # The font is JD LCD Rounded by Jecko Development 
@@ -35,6 +36,7 @@ INTER_LINE_SPACE = -15
 window : pygame.Surface = None
 font: pygame.font.Font = None
 update_queue = queue.Queue(maxsize=10)
+arrivals : list[ArrivalTime] = []
 
 def get_line_offset(line: int) -> int:
     """ Calculate the Y offset within the display for a given text line """
@@ -68,9 +70,14 @@ def write_line(line: int, text: str, text_color: Color = COLOR_LCD_AMBER):
     vertical_offset = get_line_offset(line)
     window.blit(text_img, dest=(XOFFSET_ROUTE, vertical_offset))
 
+def get_arrivals() -> list[ArrivalTime]:
+    """ Retrieves the current departures list. """
+    return arrivals
 
 def update_screen(config: Config, updates: list[ArrivalTime]) -> None:
     """ Repaint the screen with the new arrival times """
+    global arrivals
+    arrivals = updates
     updates = updates[0:LINE_COUNT] # take the first X lines
     for line_num, update in enumerate(updates):
         # Find what color we need to use for the ETA
@@ -141,9 +148,13 @@ def main():
                            routes_for_stops=config.routes_for_stops(),
                            update_queue=update_queue, 
                            update_interval_seconds=config.update_interval_seconds)
-
     scheduler.start()
 
+    # Start HTTP server
+    if config.http_server:
+      server = ArrivalsServer(get_arrivals=get_arrivals)
+      server.start()
+
     # Main event loop
     running = True
     while running: