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package main
import (
"fmt"
"log"
"net/http"
"net/url"
"strconv"
)
type Humidity float32
type HumidityHandler struct {
Building
}
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.Building.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.Building[room]
if !ok {
badRequest(w, "invalid room ID: '%s'", room)
return
}
record.put <- Humidity(humidity)
}
// Parse the value associated with each key in the query string. Returns a map of
// keys and values, or error if one of the keys is missing or if there is no value
// associated with one of the keys.
func parseQuery(query string, keys []string) (map[string]string, error) {
queryVals, err := url.ParseQuery(query)
if err != nil {
return nil, err
}
vals := make(map[string]string)
for _, key := range keys {
val := queryVals.Get(key)
if val == "" {
return nil, fmt.Errorf("missing key '%s'", key)
}
vals[key] = val
}
return vals, nil
}
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