Adds a lib for server sent events. bump version.

Author: byteface

domonic/webapi/messaging.py

@@ -0,0 +1,5 @@
+"""
+    domonic.webapi.messaging
+    ====================================
+    https://developer.mozilla.org/en-US/docs/Web/API/Channel_Messaging_API
+"""

domonic/webapi/sse.py

@@ -0,0 +1,151 @@
+"""
+    domonic.webapi.sse
+    ====================================
+    https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events
+
+    TODO - consider a blocking verison?
+    TODO - port one of the polyfills?
+    https://github.com/EventSource/eventsource/blob/master/lib/eventsource.js
+    https://github.com/remy/polyfills/blob/master/EventSource.js
+    https://github.com/Yaffle/EventSource/blob/master/src/eventsource.js
+
+    # TESTING - useage example... clone this and point at the stream
+    # https://github.com/byteface/SSELoggerDemo
+
+"""
+
+from domonic.events import MessageEvent, EventTarget
+
+
+class EventSource(EventTarget):
+    # https://developer.mozilla.org/en-US/docs/Web/API/EventSource
+
+    CONNECTING = 0
+    OPEN = 1
+    CLOSED = 2
+
+    def __init__(self, url, eventSourceInitDict=None, **kwargs):
+        """
+        The EventSource interface provides the ability to asynchronously receive messages from a server using simple push paradigm.
+        """
+        eventSourceInitDict = eventSourceInitDict or kwargs
+        super().__init__()
+        self._url = url
+        self._readyState = EventSource.CLOSED
+        self._withCredentials = eventSourceInitDict.get('withCredentials', False)
+        self._lastEventId = eventSourceInitDict.get('lastEventId', None)
+
+        self._onmessage = eventSourceInitDict.get('onmessage', None)
+        self._onerror = eventSourceInitDict.get('onerror', None)
+        self._onopen = eventSourceInitDict.get('onopen', None)
+        self._onreadystatechange = eventSourceInitDict.get('onreadystatechange', None)
+
+        # from sseclient import SSEClient
+        # messages = SSEClient(url)
+        # self._readyState = EventSource.OPEN
+        # for msg in messages:
+        #     self.onmessage(MessageEvent(msg))
+        #     print(msg)
+        # self._readyState = EventSource.CLOSED
+
+        def _do_stuff():
+            from sseclient import SSEClient
+            messages = SSEClient(url)
+            self._readyState = EventSource.OPEN
+            # self.onopen(MessageEvent(messages))
+            for msg in messages:
+                self.onmessage(MessageEvent(msg))
+                # print(msg)
+            self._readyState = EventSource.CLOSED
+
+        # TODO - use a thread or it will block the main thread
+        import threading
+
+        # def _on_message(msg):
+        #     self.onmessage(MessageEvent(msg))
+        #     print(msg)
+        #     self._readyState = EventSource.OPEN
+
+        # def _on_error(err):
+        #     self.onerror(err)
+        #     self._readyState = EventSource.CLOSED
+
+        # def _on_open(msg):
+        #     self.onopen(msg)
+        #     self._readyState = EventSource.OPEN
+
+        # def _on_ready_state_change(msg):
+        #     self.onreadystatechange(msg)
+        #     self._readyState = EventSource.OPEN
+
+        # def _on_close(msg):
+        #     self.onclose(msg)
+        #     self._readyState = EventSource.CLOSED
+
+        self._thread = threading.Thread(target=_do_stuff)
+        self._thread.start()
+
+        # print('this is so cool!')
+
+    @property
+    def readyState(self):
+        """ A number representing the state of the connection.
+        Possible values are CONNECTING (0), OPEN (1), or CLOSED (2). """
+        return self._readyState
+
+    @property
+    def url(self):
+        """ A DOMString representing the URL of the source. """
+        return self._url
+
+    @property
+    def withCredentials(self):
+        """ A boolean value indicating whether the EventSource object was
+          instantiated with cross-origin (CORS) credentials
+        set (true), or not (false, the default). """
+        return self._withCredentials
+
+    def close(self):
+        """ Closes the connection to the EventSource. """
+        self._readyState = EventSource.CLOSED
+        # close the thread
+        self._thread.join()
+        self._thread = None
+
+    def onreadystatechange(self, event):
+        """ Called when the state of the connection changes. """
+        pass
+
+    def onmessage(self, event):
+        """ Called when a message is received. """
+        if self._onmessage is not None:
+            self._onmessage(event)
+
+    def onerror(self, event):
+        """ Called when an error occurs. """
+        pass
+
+    def onopen(self, event):
+        """ Called when the connection is established. """
+        pass
+
+    # '''
+    # NOTE - if we write custom one rather than use lib...
+    # def _poll(self):
+
+    #     if self._readyState == EventSource.CLOSED:
+    #         return
+
+    #     url = 'http://domain.com/events'
+    #     headers = {
+    #         'Accept': 'text/event-stream',
+    #         'Cache-Control': 'no-cache',
+    #         'X-requested-with': 'XMLHttpRequest'
+    #     }
+    #     if self._lastEventId != None:
+    #         headers['Last-Event-ID'] = self._lastEventId
+
+    #     import requests
+    #     response = requests.get(url, stream=True, headers=headers)
+    #    # TODO - parse repsonse
+    # '''