feat(server-go): 和风天气接入与高发病天气预警规则（#12）

server-go/internal/service/weather.go

@@ -0,0 +1,133 @@
+package service
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strconv"
+	"time"
+)
+
+const qweatherAPIBase = "https://devapi.qweather.com"
+
+// WeatherNow 实时天气
+type WeatherNow struct {
+	Temp     float64 `json:"temp"`
+	Humidity float64 `json:"humidity"`
+	Text     string  `json:"text"`
+}
+
+// DailyForecast 逐日预报
+type DailyForecast struct {
+	Date      string  `json:"date"`
+	TextDay   string  `json:"textDay"`
+	TextNight string  `json:"textNight"`
+	TempMax   float64 `json:"tempMax"`
+	TempMin   float64 `json:"tempMin"`
+	Humidity  float64 `json:"humidity"`
+}
+
+// WeatherService 和风天气客户端（未配置时 Configured()=false，调用返回明确错误）
+type WeatherService struct {
+	key      string
+	location string
+	baseURL  string
+	client   *http.Client
+}
+
+// NewWeatherService 创建和风天气客户端
+func NewWeatherService(key, location string) *WeatherService {
+	return &WeatherService{
+		key:      key,
+		location: location,
+		baseURL:  qweatherAPIBase,
+		client:   &http.Client{Timeout: 15 * time.Second},
+	}
+}
+
+// Configured 是否已配置 API Key 与位置
+func (s *WeatherService) Configured() bool {
+	return s.key != "" && s.location != ""
+}
+
+// FetchNow 实时天气
+func (s *WeatherService) FetchNow(ctx context.Context) (*WeatherNow, error) {
+	var out struct {
+		Code string `json:"code"`
+		Now  struct {
+			Temp     string `json:"temp"`
+			Text     string `json:"text"`
+			Humidity string `json:"humidity"`
+		} `json:"now"`
+	}
+	if err := s.get(ctx, "/v7/weather/now", &out); err != nil {
+		return nil, err
+	}
+	temp, _ := strconv.ParseFloat(out.Now.Temp, 64)
+	hum, _ := strconv.ParseFloat(out.Now.Humidity, 64)
+	return &WeatherNow{Temp: temp, Humidity: hum, Text: out.Now.Text}, nil
+}
+
+// FetchDaily 未来 3 天预报
+func (s *WeatherService) FetchDaily(ctx context.Context) ([]DailyForecast, error) {
+	var out struct {
+		Code  string `json:"code"`
+		Daily []struct {
+			FxDate    string `json:"fxDate"`
+			TextDay   string `json:"textDay"`
+			TextNight string `json:"textNight"`
+			TempMax   string `json:"tempMax"`
+			TempMin   string `json:"tempMin"`
+			Humidity  string `json:"humidity"`
+		} `json:"daily"`
+	}
+	if err := s.get(ctx, "/v7/weather/3d", &out); err != nil {
+		return nil, err
+	}
+	list := make([]DailyForecast, 0, len(out.Daily))
+	for _, d := range out.Daily {
+		max, _ := strconv.ParseFloat(d.TempMax, 64)
+		min, _ := strconv.ParseFloat(d.TempMin, 64)
+		hum, _ := strconv.ParseFloat(d.Humidity, 64)
+		list = append(list, DailyForecast{
+			Date: d.FxDate, TextDay: d.TextDay, TextNight: d.TextNight,
+			TempMax: max, TempMin: min, Humidity: hum,
+		})
+	}
+	return list, nil
+}
+
+// get 发起 GET 并校验 code=200
+func (s *WeatherService) get(ctx context.Context, path string, out any) error {
+	if !s.Configured() {
+		return fmt.Errorf("天气服务未配置（QWEATHER_API_KEY/QWEATHER_LOCATION）")
+	}
+	u := s.baseURL + path + "?location=" + url.QueryEscape(s.location) + "&key=" + url.QueryEscape(s.key)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
+	if err != nil {
+		return err
+	}
+	resp, err := s.client.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return err
+	}
+	if err := json.Unmarshal(body, out); err != nil {
+		return err
+	}
+	var head struct {
+		Code string `json:"code"`
+	}
+	_ = json.Unmarshal(body, &head)
+	if head.Code != "200" {
+		return fmt.Errorf("和风天气返回错误 code=%s", head.Code)
+	}
+	return nil
+}