Load multiple frames at once and universal support for to_JSON in frames

meterbus/__init__.py

@@ -47,7 +47,35 @@ def load(data):
     if not data:
         raise MBusFrameDecodeError("empty frame", data)
 
-    if isinstance(data, str):
+    data = convert_data(data)
+
+    for Frame in (TelegramACK, TelegramShort, TelegramControl,
+                  TelegramLong, WTelegramSndNr):
+        try:
+            return Frame.parse(data)
+
+        except FrameMismatch as e:
+            pass
+
+    raise MBusFrameDecodeError("unable to decode frame")
+
+
+def load_all(data):
+    if not data:
+        raise MBusFrameDecodeError("empty frame", data)
+
+    dats = split_frames(convert_data(data))
+
+    return [load(d) for d in dats]
+
+
+def convert_data(data):
+
+    if isinstance(data, list):
+        # assume that the data is already processed and quickly return it
+        return data
+
+    elif isinstance(data, str):
         data = list(map(ord, data))
 
     elif isinstance(data, bytes):
@@ -56,18 +84,52 @@ def load(data):
     elif isinstance(data, bytearray):
         data = list(data)
 
-    elif isinstance(data, list):
-        pass
+    return data
 
-    for Frame in [WTelegramSndNr, TelegramACK, TelegramShort, TelegramControl,
-                  TelegramLong]:
-        try:
-            return Frame.parse(data)
 
-        except FrameMismatch as e:
-            pass
+def split_frames(data):
+    """
+    try to extract more then one frame from data and return a list
+    of frames
+
+    there are user cases in tcp connection when more then one frame
+    is received from the slave in one batch. These are long frames
+    in all the user cases, but the split function is designed to
+    be more generic and able to split all kinds of mbus frames
+    """
+
+    data = convert_data(data)
+    # or assume the data is already converted and skip this step
+
+    if data is None or len(data) == 0:
+        raise MBusFrameDecodeError("Data is None")
+
+    while len(data) > 0:
+        # ack
+        if data[0] == 0xE5:
+            yield data[:1]
+            data = data[1:]
+            continue
+
+        # short frame
+        elif len(data) >= 5 and data[0] == 0x10 and data[4] == 0x16:
+            yield data[:5]
+            data = data[5:]
+            continue
+
+        # long/control frame (+6 is for the header)
+        elif data[0] == 0x68 and data[3] == 0x68 and data[1] == data[2] \
+                and len(data) >= data[1]+6 and data[data[1]+6-1] == 0x16:
+            yield data[:data[1] + 6]
+            data = data[data[1] + 6:]
+            continue
+
+        else:
+            raise MBusFrameDecodeError("invalid data")
+            # or could consume data by bytes
+            # data = data[1:]
+
 
-    raise MBusFrameDecodeError("unable to decode frame")
 
 def debug(state):
   g.debug = state

meterbus/telegram_ack.py

@@ -1,3 +1,5 @@
+import simplejson as json
+
 from .exceptions import MBusFrameDecodeError, MBusFrameCRCError, FrameMismatch
 
 
@@ -24,3 +26,12 @@ def __len__(self):
 
     def __iter__(self):
         yield 0xE5
+
+    @property
+    def interpreted(self):
+        return {
+            'ack': hex(0xE5)
+        }
+
+    def to_JSON(self):
+        return json.dumps(self.interpreted, sort_keys=True, indent=4, use_decimal=True)

meterbus/telegram_body.py

@@ -225,7 +225,7 @@ def isLSBOrder(self):
 
     @property
     def noDataHeader(self):
-        return (self._ci_field.parts and self._ci_field.parts[0] == 0x78)
+        return (self._ci_field.parts and self._ci_field.parts[0] in (0x78, 0x51) )
 
     @property
     def isVariableData(self):

meterbus/telegram_control.py

@@ -1,3 +1,5 @@
+import simplejson as json
+
 from .telegram_body import TelegramBody
 from .telegram_header import TelegramHeader
 from .exceptions import MBusFrameCRCError, MBusFrameDecodeError, FrameMismatch
@@ -61,6 +63,12 @@ def body(self):
     def body(self, value):
         self._body = value
 
+    @property
+    def interpreted(self):
+        return {
+            'head': self.header.interpreted
+        }
+
     def compute_crc(self):
         return (self.header.cField.parts[0] +
                 self.header.aField.parts[0] +
@@ -69,6 +77,9 @@ def compute_crc(self):
     def check_crc(self):
         return self.compute_crc() == self.header.crcField.parts[0]
 
+    def to_JSON(self):
+        return json.dumps(self.interpreted, sort_keys=True, indent=4, use_decimal=True)
+
     def __len__(self):
        return 0x09
 

meterbus/telegram_header.py

@@ -91,6 +91,7 @@ def load(self, hat):
             self.lField = header[1]
             self.lField = header[2]      # Re-set
             self.startField = header[3]  # Re-set
+            # TODO check equality of re-set bytes
             self.cField = header[4]
             self.aField = header[5]
             self.crcField = header[-2]

meterbus/telegram_long.py

@@ -11,12 +11,16 @@ def parse(data):
         if data is None:
             raise MBusFrameDecodeError("Data is None")
 
-        if data is not None and len(data) < 9:
+        if len(data) < 9:
             raise MBusFrameDecodeError("Invalid M-Bus length")
 
         if data[0] != 0x68:
             raise FrameMismatch()
 
+        if data[1] != data[2] or len(data) != data[1] + 6:
+            print('not a single long', len(data), data[1])
+            raise FrameMismatch()  # to be able to parse multiple frames
+
         return TelegramLong(data)
 
     def __init__(self, dbuf=None):

meterbus/telegram_short.py

@@ -1,3 +1,5 @@
+import simplejson as json
+
 from .defines import *
 from .telegram_header import TelegramHeader
 from .exceptions import MBusFrameDecodeError, MBusFrameCRCError, FrameMismatch