Implement wrapper class for the BTLE UART

solar_ble.py

@@ -1,9 +1,17 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
+
 import datetime
+import io
+import queue
 import struct
 import sys
 import time
+from queue import Queue
+from typing import TYPE_CHECKING, Optional, cast
+
+if TYPE_CHECKING:
+    from _typeshed import ReadableBuffer, WriteableBuffer
 
 from bluepy import btle
 from libscrc import modbus
@@ -13,8 +21,8 @@ INTERVAL = 15
 
 # write_service = "0000ffd0-0000-1000-8000-00805f9b34fb"
 # read_service  = "0000fff0-0000-1000-8000-00805f9b34fb"
-write_device = "0000ffd1-0000-1000-8000-00805f9b34fb"
+WRITE_DEVICE = "0000ffd1-0000-1000-8000-00805f9b34fb"
-# read_device   = "0000fff1-0000-1000-8000-00805f9b34fb"
+READ_DEVICE = "0000fff1-0000-1000-8000-00805f9b34fb"
 
 # get(255, 12, 2)
 # "ff 03 00 0c 00 02"
@@ -222,6 +230,172 @@ class Delegate(btle.DefaultDelegate):
             self.data.clear()
 
 
+class BTLEUart(io.RawIOBase):
+    mac: str
+    write_endpoint: str
+    read_endpoint: str
+    timeout: float
+
+    device: Optional[btle.Peripheral] = None
+    _write_handle: Optional[btle.Characteristic] = None
+    _read_handle: Optional[btle.Characteristic] = None
+    delegate: "_QueueDelegate"
+    _read_buffer: bytearray
+
+    class _QueueDelegate(btle.DefaultDelegate):
+        queue: Queue
+        handle: Optional[int]
+
+        def __init__(self, queue, handle=None):
+            self.queue = queue
+            self.handle = handle
+
+        def handleNotification(self, cHandle: int, data: bytes):
+            # print("Notification:", cHandle, "sent data", binascii.b2a_hex(data))
+
+            if self.handle is not None and cHandle != self.handle:
+                return
+
+            self.queue.put(data)
+
+    def __init__(
+        self,
+        mac: str,
+        write_endpoint: str = WRITE_DEVICE,
+        read_endpoint: str = READ_DEVICE,
+        timeout: float = 30,
+    ):
+        self.mac = mac
+        self.write_endpoint = write_endpoint
+        self.read_endpoint = read_endpoint
+        self.timeout = timeout
+
+        self.delegate = self._QueueDelegate(Queue())
+        self._read_buffer = bytearray()
+
+        self._connect()
+
+    def _ensure_connected(self):
+        if self.device is None:
+            self._connect()
+
+    def _poll(self, timeout: float = 0.0001):
+        self._ensure_connected()
+        if TYPE_CHECKING:
+            self.device = cast(btle.Peripheral, self.device)
+
+        start = time.time()
+        left = timeout - (time.time() - start)
+        while self.device.waitForNotifications(max(left, 0) or 0.0001):
+            left = timeout - (time.time() - start)
+            if left < 0:
+                break
+
+    def _connect(self):
+        try:
+            del self.device
+        except Exception:
+            pass
+        self.device = btle.Peripheral(self.mac).withDelegate(self.delegate)
+        self._read_handle = self.device.getCharacteristics(uuid=self.read_endpoint)[0]
+        # self.delegate.handle = self._read_handle.handle
+        self._write_handle = self.device.getCharacteristics(uuid=self.write_endpoint)[0]
+        # print("Handles:", self._read_handle.handle, self._write_handle.handle)
+
+    def _read(self, num: Optional[int] = None, timeout: Optional[float] = None):
+        self._ensure_connected()
+        if TYPE_CHECKING:
+            self.device = cast(btle.Peripheral, self.device)
+
+        if timeout is None:
+            timeout = self.timeout
+
+        if num is None:
+            start = time.time()
+            while not len(self._read_buffer):
+                left = timeout - (time.time() - start)
+                if left < 0:
+                    break
+                self.device.waitForNotifications(0.1)
+                try:
+                    self._read_buffer.extend(self.delegate.queue.get_nowait())
+                except queue.Empty:
+                    pass
+            try:
+                while True:
+                    self.device.waitForNotifications(0.01)
+                    self._read_buffer.extend(self.delegate.queue.get_nowait())
+
+            except queue.Empty:
+                pass
+        else:
+            start = time.time()
+            while len(self._read_buffer) < num:
+                left = timeout - (time.time() - start)
+                if left < 0:
+                    break
+                self.device.waitForNotifications(0.1)
+                try:
+                    self._read_buffer.extend(self.delegate.queue.get_nowait())
+                except queue.Empty:
+                    pass
+
+        if num is None:
+            data = bytes(self._read_buffer.copy())
+            self._read_buffer.clear()
+        else:
+            data = bytes(self._read_buffer[:num])
+            del self._read_buffer[:num]
+        return data or None
+
+    def readinto(self, buffer: "WriteableBuffer") -> Optional[int]:
+        data = self._read(len(buffer))
+
+        if data is None:
+            return None
+
+        buffer[: len(data)] = data
+        return len(data)
+
+    def readall(self) -> bytes:
+        return self._read()
+
+    def write(self, b: "ReadableBuffer") -> Optional[int]:
+        self._ensure_connected()
+        if TYPE_CHECKING:
+            self.device = cast(btle.Peripheral, self.device)
+
+        if self._write_handle is None:
+            raise IOError("write_handle not open")
+        self._write_handle.write(b, withResponse=True)
+        return len(b)
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self):
+        self.device.disconnect()
+
+    def seekable(self) -> bool:
+        return False
+
+    def readable(self) -> bool:
+        return True
+
+    def writable(self) -> bool:
+        return True
+
+    # dlgt = Delegate()
+
+    # prev = time.time() - INTERVAL
+
+    # while True:
+    #    try:
+    #        log("Connecting...")
+    #        with btle.Peripheral(MAC).withDelegate(dlgt) as dev:
+    #            wd = dev.getCharacteristics(uuid=write_device)[0]
+
+
 def write(fh, data):
     bdata = bytes(data)
     crc = modbus(bdata)
@@ -279,7 +453,7 @@ if __name__ == "__main__":
         try:
             log("Connecting...")
             with btle.Peripheral(MAC).withDelegate(dlgt) as dev:
-                wd = dev.getCharacteristics(uuid=write_device)[0]
+                wd = dev.getCharacteristics(uuid=WRITE_DEVICE)[0]
 
                 log("Connected.")
 

test_bleuart.py

@@ -0,0 +1,16 @@
+# -*- coding: utf-8 -*-
+from solar_ble import MAC, BTLEUart, construct_request, write
+
+x = BTLEUart(MAC)
+
+print(x)
+write(x, construct_request(0x0C, 8))
+
+print(x.read(3))
+print(x.read(8 * 2))
+print(x.read(2))
+
+x.timeout = 10
+
+print(x.read())
+print(x.read(1))