Merge pull request #63 from mjkl-gh/master

Improve documentation asyncio

README.rst

@@ -39,10 +39,6 @@ process because the code is blocking (not asynchronous):
      for telegram in serial_reader.read():
          print(telegram)  # see 'Telegram object' docs below
 
-**AsyncIO client**
-
-To be documented.
-
 **Socket client**
 
 Read a remote serial port (for example using ser2net) and work with the parsed telegrams.
@@ -62,6 +58,115 @@ It should be run in a separate process because the code is blocking (not asynchr
      for telegram in socket_reader.read():
          print(telegram)  # see 'Telegram object' docs below
 
+**AsyncIO client**
+
+For a test run using a tcp server (lasting 20 seconds) use the following example:
+
+.. code-block:: python
+    import asyncio
+    import logging
+    from dsmr_parser import obis_references
+    from dsmr_parser.clients.protocol import create_dsmr_reader, create_tcp_dsmr_reader
+
+    logging.basicConfig(level=logging.INFO, format='%(message)s')
+
+    HOST = MY_HOST
+    PORT = MY_PORT
+    DSMR_VERSION = MY_DSMR_VERSION
+
+    logger = logging.getLogger('tcpclient')
+    logger.debug("Logger created")
+
+    def printTelegram(telegram):
+        logger.info(telegram)
+
+
+    async def main():
+        try:
+            logger.debug("Getting loop")
+            loop = asyncio.get_event_loop()
+            logger.debug("Creating reader")
+            await 	create_tcp_dsmr_reader(
+                                HOST,
+                                PORT,
+                                DSMR_VERSION,
+                                printTelegram,
+                                loop
+                                )
+            logger.debug("Reader created going to sleep now")					
+            await asyncio.sleep(20)
+            logger.info('Finished run')					
+        except Exception as e:
+            logger.error("Unexpected error: "+ e)
+
+    asyncio.run(main())
+
+Note the creation of a callback function to call when a telegram is received. In this case `printTelegram`. Normally the used loop is the one running.
+
+Currently the asyncio implementation does not support returning telegram objects directly as a `read_as_object()` for async tcp is currently not implemented.
+Moreover, the telegram passed to `telegram_callback(telegram)` is already parsed. Therefore we can't feed it into the telegram constructor directly as that expects unparsed telegrams
+
+However, if we construct a mock TelegramParser that just returns the already parsed object we can work around this. An example is below:
+
+.. code-block:: python
+    import asyncio
+    import logging
+    #from dsmr_parser import obis_references
+    #from dsmr_parser import telegram_specifications
+    #from dsmr_parser.clients.protocol import create_dsmr_reader, create_tcp_dsmr_reader
+    #from dsmr_parser.objects import Telegram
+
+    logging.basicConfig(level=logging.INFO, format='%(message)s')
+
+    HOST = MY_HOST
+    PORT = MY_PORT
+    DSMR_VERSION = MY_DSMR_VERSION
+
+    logger = logging.getLogger('tcpclient')
+    logger.debug("Logger created")
+
+    class mockTelegramParser(object):
+
+        def parse(self, telegram):
+            return telegram
+
+    telegram_parser = mockTelegramParser()
+
+    def printTelegram(telegram):
+        try:
+            logger.info(Telegram(telegram, telegram_parser, telegram_specifications.V4))
+        except InvalidChecksumError as e:
+            logger.warning(str(e))
+        except ParseError as e:
+            logger.error('Failed to parse telegram: %s', e)
+
+
+    async def main():
+        try:
+            logger.debug("Getting loop")
+            loop = asyncio.get_event_loop()
+            logger.debug("Creating reader")
+            await 	create_tcp_dsmr_reader(
+                                HOST,
+                                PORT,
+                                DSMR_VERSION,
+                                printTelegram,
+                                loop
+                                )
+            logger.debug("Reader created going to sleep now")					
+            while True:
+                await asyncio.sleep(1)
+        except Exception as e:
+            logger.error("Unexpected error: "+ e)
+            raise
+
+    if __name__ == '__main__':
+        try:
+            asyncio.run(main())
+        except (KeyboardInterrupt, SystemExit):
+            logger.info('Closing down...')					
+        except Exception as e:
+            logger.error("Unexpected error: "+ e)
 
 Parsing module usage
 --------------------