1 files changed, 79 insertions, 0 deletions
diff --git a/src/si7021d.py b/src/si7021d.py
new file mode 100755
index 0000000..fe11787
--- /dev/null
+++ b/src/si7021d.py
@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+import smbus
+import argparse
+import asyncio
+import json
+import logging
+
+from home.config import config
+from home.util import parse_addr
+
+logger = logging.getLogger(__name__)
+bus = None
+lock = asyncio.Lock()
+delay = 0.01
+
+
+async def si7021_read():
+    async with lock:
+        await asyncio.sleep(delay)
+
+        # these are still blocking... meh
+        raw = bus.read_i2c_block_data(0x40, 0xE3, 2)
+        temp = 175.72 * (raw[0] << 8 | raw[1]) / 65536.0 - 46.85
+
+        raw = bus.read_i2c_block_data(0x40, 0xE5, 2)
+        rh = 125.0 * (raw[0] << 8 | raw[1]) / 65536.0 - 6.0
+
+        return rh, temp
+
+
+async def handle_client(reader, writer):
+    request = None
+    while request != 'quit':
+        try:
+            request = await reader.read(255)
+            if request == b'\x04':
+                break
+            request = request.decode('utf-8').strip()
+        except Exception:
+            break
+
+        if request == 'read':
+            try:
+                rh, temp = await asyncio.wait_for(si7021_read(), timeout=3)
+                data = dict(humidity=rh, temp=temp)
+            except asyncio.TimeoutError as e:
+                logger.exception(e)
+                data = dict(error='i2c call timed out')
+        else:
+            data = dict(error='invalid request')
+
+        writer.write((json.dumps(data) + '\r\n').encode('utf-8'))
+        try:
+            await writer.drain()
+        except ConnectionResetError:
+            pass
+
+    writer.close()
+
+
+async def run_server(host, port):
+    server = await asyncio.start_server(handle_client, host, port)
+    async with server:
+        logger.info('Server started.')
+        await server.serve_forever()
+
+
+if __name__ == '__main__':
+    config.load()
+
+    host, port = parse_addr(config['server']['listen'])
+
+    delay = float(config['smbus']['delay'])
+    bus = smbus.SMBus(int(config['smbus']['bus']))
+
+    try:
+        asyncio.run(run_server(host, port))
+    except KeyboardInterrupt:
+        logging.info('Exiting...')