weather: start simple weather application

Simple weather application, using open-meteo.com data. Once an hour
weather is fetched and temperature/wind/sky condition is displayed.

internal_filesystem/apps/cz.ucw.pavel.weather/META-INF/MANIFEST.JSON

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+{
+"name": "Weather",
+"publisher": "Pavel Machek",
+"short_description": "Display weather information.",
+"long_description": "This displays weather information from open-meteo.com.",
+"icon_url": "https://apps.micropythonos.com/apps/cz.ucw.pavel.weather/icons/cz.ucw.pavel.weather_0.0.1_64x64.png",
+"download_url": "https://apps.micropythonos.com/apps/cz.ucw.pavel.weather/mpks/cz.ucw.pavel.weather_0.0.1.mpk",
+"fullname": "cz.ucw.pavel.weather",
+"version": "0.0.1",
+"category": "utilities",
+"activities": [
+    {
+      "entrypoint": "assets/main.py",
+      "classname": "Main",
+      "intent_filters": [
+        {
+          "action": "main",
+          "category": "launcher"
+        }
+      ]
+    }
+  ]
+}
+

internal_filesystem/apps/cz.ucw.pavel.weather/assets/main.py

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+from mpos import Activity
+
+"""
+Look at https://open-meteo.com/en/docs , then design an application that would display current time and weather, and summary of forecast ("no change expected for 2 days" or maybe "rain in 5 hours"), with a way to access detailed forecast.
+"""
+
+import time
+import os
+
+try:
+    import lvgl as lv
+except ImportError:
+    pass
+
+from mpos import Activity, MposKeyboard
+
+import ujson
+import utime
+import usocket as socket
+import ujson
+
+# -----------------------------
+# WEATHER DATA MODEL
+# -----------------------------
+
+class WData:
+    WMO_CODES = {
+        0: "Clear sky",
+        1: "Mainly clear",
+        2: "Partly cloudy",
+        3: "Overcast",
+        45: "Fog",
+        48: "Rime fog",
+        51: "Light drizzle",
+        53: "Drizzle",
+        55: "Heavy drizzle",
+        56: "Freezing drizzle",
+        57: "Freezing drizzle",
+        61: "Light rain",
+        63: "Rain",
+        65: "Heavy rain",
+        66: "Freezing rain",
+        67: "Freezing rain",
+        71: "Light snow",
+        73: "Snow",
+        75: "Heavy snow",
+        77: "Snow grains",
+        80: "Rain showers",
+        81: "Rain showers",
+        82: "Heavy rain showers",
+        85: "Snow showers",
+        86: "Heavy snow showers",
+        95: "Thunderstorm",
+        96: "Thunderstorm + hail",
+        99: "Thunderstorm + hail",
+    }
+
+    def code_to_text(self, code):
+        return self.WMO_CODES.get(int(code), "Unknown")
+
+class Hourly(WData):
+    def __init__(self, cw):
+        self.temp = cw["temperature_2m"]
+        self.wind = cw["windspeed"]
+        self.code = self.code_to_text(cw["weather_code"])
+
+    def summarize(self):
+        return f"{self.code}\nTemp {self.temp}\nWind {self.wind}"
+
+class Weather:
+    name = "Prague"
+    lat = 50.08
+    lon = 14.44
+    
+    def __init__(self):
+        self.now = None
+        self.hourly = []
+        self.daily = []
+        self.summary = "(no weather)"
+
+    def fetch(self):
+        self.summary = "...fetching..."
+
+        # See https://open-meteo.com/en/docs?forecast_days=1&current=relative_humidity_2m
+        
+        host = "api.open-meteo.com"
+        port = 80  # HTTP only
+        path = (
+            "/v1/forecast?"
+            "latitude={}&longitude={}"
+            "&current=temperature_2m,dewpoint_2m,pressure_msl,precipitation,weather_code,windspeed"
+            "&timezone=auto"
+        ).format(self.lat, self.lon)
+
+        print("Weather fetch: ", path)
+
+        # Resolve DNS
+        addr = socket.getaddrinfo(host, port, socket.AF_INET)[0][-1]
+        print("DNS", addr)
+
+        s = socket.socket()
+        s.connect(addr)
+
+        # Send HTTP request
+        request = (
+            "GET {} HTTP/1.1\r\n"
+            "Host: {}\r\n"
+            "Connection: close\r\n\r\n"
+        ).format(path, host)
+
+        s.send(request.encode())
+
+        # ---- Read response ----
+        # Skip HTTP headers
+        buffer = b""
+        while True:
+            chunk = s.recv(256)
+            if not chunk:
+                raise Exception("No response")
+            buffer += chunk
+            header_end = buffer.find(b"\r\n\r\n")
+            if header_end != -1:
+                body = buffer[header_end + 4:]
+                break
+
+
+        # Read remaining body
+        while True:
+            chunk = s.recv(512)
+            if not chunk:
+                break
+            body += chunk
+
+        s.close()
+
+        # Strip non-json parts
+        body = body[5:]
+        body = body[:-7]
+
+        print("Have result:", body.decode())
+
+        # Parse JSON
+        data = ujson.loads(body)
+
+        # ---- Extract data ----
+        cw = data["current"]
+        self.now = Hourly(cw)
+        self.summary = self.now.summarize()
+        
+weather = Weather()
+        
+# ------------------------------------------------------------
+# Main activity
+# ------------------------------------------------------------
+
+class Main(Activity):
+    def __init__(self):
+        self.last_hour = 0
+        super().__init__()
+
+     # --------------------
+
+    def onCreate(self):
+        self.screen = lv.obj()
+        #self.screen.remove_flag(lv.obj.FLAG.SCROLLABLE)
+        scr_main = self.screen
+
+        # ---- MAIN SCREEN ----
+
+        label_time = lv.label(scr_main)
+        label_time.set_text("(time)")
+        label_time.align(lv.ALIGN.TOP_LEFT, 10, 40)
+        label_time.set_style_text_font(lv.font_montserrat_24, 0)
+        self.label_time = label_time
+
+        label_weather = lv.label(scr_main)
+        label_weather.set_text(f"Weather for {weather.name} ({weather.lat}, {weather.lon})")
+        label_weather.align_to(label_time, lv.ALIGN.OUT_BOTTOM_LEFT, 0, 10)
+        label_weather.set_style_text_font(lv.font_montserrat_14, 0)
+        self.label_weather = label_weather
+
+        label_summary = lv.label(scr_main)
+        label_summary.set_text("(weather)")
+        #label_summary.set_long_mode(lv.label.LONG.WRAP)
+        label_summary.set_width(300)
+        label_summary.align_to(label_weather, lv.ALIGN.OUT_BOTTOM_LEFT, 0, 5)
+        label_summary.set_style_text_font(lv.font_montserrat_24, 0)
+        self.label_summary = label_summary
+
+        btn_hourly = lv.button(scr_main)
+        btn_hourly.set_size(100, 40)
+        btn_hourly.align(lv.ALIGN.BOTTOM_LEFT, 10, -10)
+        lv.label(btn_hourly).set_text("Reload")
+
+        btn_hourly.add_event_cb(lambda x: self.do_load(), lv.EVENT.CLICKED, None)
+
+        self.setContentView(self.screen)
+
+    def onResume(self, screen):
+        self.timer = lv.timer_create(self.tick, 15000, None)
+        self.tick(0)
+
+    def onPause(self, screen):
+        if self.timer:
+            self.timer.delete()
+            self.timer = None
+
+    # --------------------
+
+    def tick(self, t):
+        now = time.localtime()
+        y, m, d = now[0], now[1], now[2]
+        hh, mm, ss = now[3], now[4], now[5]
+
+        if hh != self.last_hour:
+            self.last_hour = hh
+            self.do_load()
+
+        self.label_time.set_text("%02d:%02d" % (hh, mm))
+        self.label_summary.set_text(weather.summary)
+
+    def do_load(self):
+        self.label_summary.set_text("Requesting...")
+        weather.fetch()
+