Add BTC price ticker demo

apps/com.example.wstest/assets/price.py

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+import usocket
+import ssl
+import ubinascii
+import ujson
+import urandom
+import uhashlib
+import time
+
+subwindow.clean()
+canary = lv.obj(subwindow)
+canary.add_flag(lv.obj.FLAG.HIDDEN)
+
+def compute_accept_key(key):
+    GUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
+    hash_obj = uhashlib.sha1(key + GUID)
+    return ubinascii.b2a_base64(hash_obj.digest())[:-1].decode()
+
+def ws_handshake(host, port, path="/"):
+    print(f"Connecting to {host}:{port}")
+    sock = usocket.socket(usocket.AF_INET, usocket.SOCK_STREAM)
+    addr = usocket.getaddrinfo(host, port)[0][-1]
+    print(f"Resolved: {addr}")
+    sock.connect(addr)
+
+    ssl_sock = ssl.wrap_socket(sock, server_hostname=host)
+    print("SSL handshake complete")
+
+    key_bytes = bytearray()
+    for _ in range(4):
+        key_bytes.extend(urandom.getrandbits(32).to_bytes(4, 'big'))
+    key = ubinascii.b2a_base64(key_bytes)[:-1].decode()
+    expected_accept = compute_accept_key(key)
+    print(f"Key: {key}")
+    print(f"Expected Sec-WebSocket-Accept: {expected_accept}")
+
+    handshake = (
+        f"GET {path} HTTP/1.1\r\n"
+        f"Host: {host}\r\n"
+        f"Upgrade: websocket\r\n"
+        f"Connection: Upgrade\r\n"
+        f"Sec-WebSocket-Key: {key}\r\n"
+        f"Sec-WebSocket-Version: 13\r\n"
+        f"\r\n"
+    )
+    print(f"Handshake:\n{handshake}")
+    ssl_sock.write(handshake.encode())
+
+    response = ssl_sock.readline()
+    print(f"Response: {response.decode()}")
+    if b"101" not in response:
+        ssl_sock.close()
+        raise ValueError(f"Handshake failed: {response.decode()}")
+
+    accept_key = None
+    while True:
+        line = ssl_sock.readline()
+        print(f"Header: {line.decode()}")
+        if line == b"\r\n":
+            break
+        if line.lower().startswith(b"sec-websocket-accept:"):
+            accept_key = line.decode().split(":")[1].strip()
+
+    if not accept_key:
+        ssl_sock.close()
+        raise ValueError("No Sec-WebSocket-Accept header received")
+    if accept_key != expected_accept:
+        ssl_sock.close()
+        raise ValueError(f"Invalid Sec-WebSocket-Accept: got {accept_key}, expected {expected_accept}")
+
+    # Set non-blocking read
+    ssl_sock.setblocking(False)
+    return ssl_sock
+
+def ws_send_text(sock, message):
+    print(f"Sending: {message}")
+    data = message.encode()
+    print(f"Data: {data}")
+    length = len(data)
+
+    frame = bytearray()
+    frame.append(0x81)  # FIN=1, opcode=0x1 (text)
+    mask_bit = 0x80
+    mask_key = bytearray(urandom.getrandbits(32).to_bytes(4, 'big'))
+    print(f"Mask key: {mask_key}")
+
+    if length <= 125:
+        frame.append(mask_bit | length)
+    elif length <= 65535:
+        frame.append(mask_bit | 126)
+        frame.extend(length.to_bytes(2, 'big'))
+    else:
+        frame.append(mask_bit | 127)
+        frame.extend(length.to_bytes(8, 'big'))
+
+    frame.extend(mask_key)
+    masked_data = bytearray(data)
+    for i in range(len(data)):
+        masked_data[i] ^= mask_key[i % 4]
+    frame.extend(masked_data)
+    print(f"Frame: {frame}")
+    sock.write(frame)
+
+def ws_read_frame(sock):
+    try:
+        data = sock.read(2)  # Read header (FIN/opcode, length)
+    except OSError as e:
+        print(f"Read error: {e}")
+        return None
+    if not data:
+        print("Read: empty")
+        return None
+    print(f"Raw header: {data}")
+
+    if len(data) < 2:
+        print("Frame too short")
+        return None
+
+    fin = (data[0] & 0x80) >> 7
+    opcode = data[0] & 0x0F
+    masked = (data[1] & 0x80) >> 7
+    payload_len = data[1] & 0x7F
+    print(f"FIN: {fin} Opcode: {opcode} Masked: {masked} Len: {payload_len}")
+
+    if payload_len == 126:
+        len_data = sock.read(2)
+        payload_len = int.from_bytes(len_data, 'big')
+        print(f"Extended len: {payload_len}")
+    elif payload_len == 127:
+        len_data = sock.read(8)
+        payload_len = int.from_bytes(len_data, 'big')
+        print(f"Extended len: {payload_len}")
+
+    mask_key = None
+    if masked:
+        mask_key = sock.read(4)
+        print(f"Mask key: {mask_key}")
+
+    payload = sock.read(payload_len)
+    print(f"Raw payload: {payload}")
+    if masked and mask_key:
+        payload = bytearray(payload)
+        for i in range(len(payload)):
+            payload[i] ^= mask_key[i % 4]
+    print(f"Payload: {payload}")
+
+    if opcode == 0x1:
+        return payload.decode()
+    elif opcode == 0x9:
+        print("Ping frame received")
+        return None
+    elif opcode == 0xA:
+        print("Pong frame received")
+        return None
+    elif opcode == 0x8:
+        print("Close frame received")
+        return None
+    else:
+        print(f"Unknown opcode: {opcode}")
+        return None
+
+
+
+status = lv.label(subwindow)
+status.align(lv.ALIGN.TOP_LEFT, 5, 10)
+status.set_style_text_color(lv.color_hex(0xFFFFFF), 0)
+
+summary = "Websocket sends:\n\n"
+status.set_text(summary)
+
+port = 443
+host = "ws-feed.exchange.coinbase.com"
+path = "/"
+
+try:
+    sock = ws_handshake(host, port, path)
+
+    print("Reading a bit...") # echo.websocket.org sends a reply
+    for _ in range(3):
+        time.sleep(1)
+        data = ws_read_frame(sock)
+        if data:
+            print(f"Response: {data}")
+            break
+
+    print("Subscribing to price updates...")
+    ws_send_text(sock, ujson.dumps({"type": "subscribe","product_ids": ["BTC-USD"],"channels": ["ticker_batch"]}))
+    #ws_send_text(sock, '{"type": "subscribe","product_ids": ["BTC-USD","channels": ["ticker_batch"]}')
+    while canary.is_valid():
+        time.sleep(1)            
+        data = ws_read_frame(sock)
+        if data:
+            print(f"Response: {data}")
+            summary += f"{data}\n"
+            status.set_text(summary)
+
+    sock.close()
+except Exception as e:
+    print(f"Error: {str(e)}")
+    try:
+        sock.close()
+    except:
+        pass
+
+