Changed tweets, added eca

eca/sse.py

@@ -0,0 +1,67 @@
+import queue
+from collections import namedtuple
+
+from . import httpd
+
+PendingEvent = namedtuple('PendingEvent', ['data', 'name', 'id'])
+
+class ServerSideEvents(httpd.Handler):
+    """
+    Base class for server side events. See the specification of the W3C
+    at http://dev.w3.org/html5/eventsource/
+    
+    This class handles decoupling through the default Queue. Events can be
+    posted for transmission by using send_event.
+    """
+
+    def __init__(self, request):
+        super().__init__(request)
+        self.queue = queue.Queue()
+
+    def send_event(self, data, name=None, id=None):
+        self.queue.put(PendingEvent(data, name, id))
+
+    def go_subscribe(self):
+        pass
+
+    def go_unsubscribe(self):
+        pass
+
+    def handle_GET(self):
+        self.go_subscribe()
+
+        # Send HTTP headers:
+        self.request.send_response(200)
+        self.request.send_header("Content-type", "text/event-stream")
+        self.request.end_headers()
+
+        done = False
+        while not done:
+            event = self.queue.get()
+            if event == None:
+                done = True
+            else:
+                done = not self._send_message(event)
+
+        self.go_unsubscribe()
+
+    def _send_message(self, event):
+        try:
+            if event.id is not None:
+                id_line = "id: {}\n".format(event.id)
+                self.request.wfile.write(id_line.encode('utf-8'))
+
+            if event.name is not None:
+                event_line = "event: {}\n".format(event.name)
+                self.request.wfile.write(event_line.encode('utf-8'))
+
+            data_line = "data: {}\n".format(event.data)
+            self.request.wfile.write(data_line.encode('utf-8'))
+
+            self.request.wfile.write("\n".encode('utf-8'))
+            self.request.wfile.flush()
+
+            return True
+        except IOError:
+            return False
+