1 files changed, 95 insertions, 0 deletions
diff --git a/server/humidity.go b/server/humidity.go
new file mode 100644
index 0000000..079c9bf
--- /dev/null
+++ b/server/humidity.go
@@ -0,0 +1,95 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"strconv"
+)
+
+type Humidity float32
+
+type HumidityHandler struct {
+	rooms map[RoomID]Record[Humidity]
+}
+
+func newHumidityHandler(rooms []RoomID) HumidityHandler {
+	h := HumidityHandler{make(map[RoomID]Record[Humidity])}
+	for _, id := range rooms {
+		h.rooms[id] = newRecord[Humidity]()
+	}
+	return h
+}
+
+func (h HumidityHandler) Close() {
+	for _, record := range h.rooms {
+		record.Close()
+	}
+}
+
+func (h HumidityHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	log.Println(r.Method, r.URL)
+	switch r.Method {
+	case http.MethodGet:
+		h.get(w, r)
+	case http.MethodPost:
+		h.post(w, r)
+	default:
+		w.WriteHeader(http.StatusMethodNotAllowed)
+		fmt.Fprintf(w, "invalid method: '%s'", r.Method)
+	}
+}
+
+func (h HumidityHandler) get(w http.ResponseWriter, r *http.Request) {
+	if humidity, ok := h.average(); ok {
+		fmt.Fprintf(w, "%.2f", humidity)
+	} else {
+		w.WriteHeader(http.StatusGone)
+		fmt.Fprintf(w, "no humidity data stored on server")
+	}
+}
+
+func (h HumidityHandler) post(w http.ResponseWriter, r *http.Request) {
+	queryVals, err := parseQuery(r.URL.RawQuery, []string{"room", "humidity"})
+	if err != nil {
+		badRequest(w, "invalid query: %v", err)
+		return
+	}
+	room := RoomID(queryVals["room"])
+	humidityStr := queryVals["humidity"]
+
+	humidity, err := strconv.ParseFloat(humidityStr, 32)
+	if err != nil {
+		badRequest(w, "invalid humidity: '%s'", humidityStr)
+		return
+	}
+
+	record, ok := h.rooms[room]
+	if !ok {
+		badRequest(w, "invalid room ID: '%s'", room)
+		return
+	}
+
+	record.put <- Humidity(humidity)
+}
+
+// Calculate the average humidity in the building. Returns false if there is not enough data available.
+func (h HumidityHandler) average() (Humidity, bool) {
+	var sum Humidity = 0
+	nRooms := 0
+	for room, record := range h.rooms {
+		c := make(chan Humidity)
+		record.getRecent <- c
+		if humidity, ok := <-c; ok {
+			sum += humidity
+			nRooms++
+		} else {
+			log.Printf("Warning: no humidity for room '%s'\n", room)
+		}
+	}
+	if nRooms == 0 {
+		log.Println("Warning: not enough data to calculate average humidity")
+		return -1.0, false
+	}
+	return sum / Humidity(nRooms), true
+}