Get WWBOTA data via SSE. Thanks to Steven M1SDH for the patch. Closes #4

spotproviders/sse_spot_provider.py

@@ -0,0 +1,65 @@
+import logging
+from datetime import datetime
+from threading import Thread
+from time import sleep
+
+import pytz
+from requests_sse import EventSource
+
+from spotproviders.spot_provider import SpotProvider
+
+# Spot provider using Server-Sent Events.
+class SSESpotProvider(SpotProvider):
+
+    def __init__(self, provider_config, url):
+        super().__init__(provider_config)
+        self.url = url
+        self.event_source = None
+        self.thread = None
+        self.stopped = False
+        self.last_event_id = None
+
+    def start(self):
+        logging.info("Set up SSE connection to " + self.name + " spot API.")
+        self.stopped = False
+        self.thread = Thread(target=self.run)
+        self.thread.daemon = True
+        self.thread.start()
+
+    def stop(self):
+        self.stopped = True
+        if self.event_source:
+            self.event_source.close()
+        if self.thread:
+            self.thread.join()
+
+    def run(self):
+        while not self.stopped:
+            try:
+                logging.debug("Connecting to " + self.name + " spot API...")
+                with EventSource(self.url, headers=self.HTTP_HEADERS, latest_event_id=self.last_event_id, timeout=30) as event_source:
+                    self.event_source = event_source
+                    for event in self.event_source:
+                        if event.type == 'message':
+                            try:
+                                self.last_event_id = event.last_event_id
+                                new_spot = self.sse_message_to_spot(event.data)
+                                if new_spot:
+                                    self.submit(new_spot)
+
+                                self.status = "OK"
+                                self.last_update_time = datetime.now(pytz.UTC)
+                                logging.debug("Received data from " + self.name + " spot API.")
+
+                            except Exception as e:
+                                logging.exception("Exception processing message from SSE Spot Provider (" + self.name + ")")
+
+            except Exception as e:
+                self.status = "Error"
+                logging.exception("Exception in SSE Spot Provider (" + self.name + ")")
+            sleep(5)  # Wait before trying to reconnect
+
+    # Convert an SSE message received from the API into a spot. The whole message data is provided here so the subclass
+    # implementations can handle the message as JSON, XML, text, whatever the API actually provides.
+    def sse_message_to_spot(self, message_data):
+        raise NotImplementedError("Subclasses must implement this method")