Initial commit.

cmd/smartswitch-server/main.go

@@ -0,0 +1,121 @@
+package main
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"log"
+	"net/http"
+
+	"github.com/spf13/viper"
+	"gopkg.in/yaml.v2"
+)
+
+type webhook struct {
+	Name              string
+	Path              string
+	SecretKey         string `yaml:"secret_key"`
+	NumSwitches       int    `yaml:"num_switches"`
+	MomentarySwitches []int  `yaml:"momentary_switches"`
+	SwitchStates      []int  `json:switch_states`
+}
+
+func debug(msg string, args ...interface{}) {
+	if viper.GetBool("Debug") {
+		log.Printf(msg, args...)
+	}
+}
+
+func initWebhooks(filename string) {
+	bytes, err := ioutil.ReadFile(filename)
+	if err != nil {
+		log.Panicf("Couldn't read config file: %s", err)
+	}
+
+	var hooks []webhook
+
+	err = yaml.Unmarshal(bytes, &hooks)
+	if err != nil {
+		log.Panicf("Couldn't parse webhook file: %v", err)
+	}
+
+	debug("Webhook definitions:")
+	debug("%v", hooks)
+
+	for _, v := range hooks {
+		v.SwitchStates = make([]int, v.NumSwitches)
+		http.HandleFunc("/"+v.Path, makeWebhookHandler(v))
+	}
+}
+
+func runServer() {
+	http.ListenAndServe(":"+viper.GetString("ListenPort"), nil)
+}
+
+func makeWebhookHandler(hook webhook) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		// authentication check
+		keys, ok := r.URL.Query()["key"]
+		if !ok || len(keys) == 0 {
+			log.Printf("No key found for webhook: %s", hook.Name)
+			http.NotFound(w, r)
+			return
+		}
+		providedKey := keys[0]
+
+		if providedKey == "" || providedKey != hook.SecretKey {
+			log.Printf("Failed to authenticate request for webhook: %s", hook.Name)
+			debug("Got key '%s', expected key '%s'", providedKey, hook.SecretKey)
+			http.NotFound(w, r)
+			return
+		}
+
+		// now actually handle the request
+		if r.Method == "GET" {
+			webhookRead(hook, w, r)
+
+		} else if r.Method == "POST" {
+			webhookWrite(hook, w, r)
+		}
+	}
+}
+
+func webhookRead(hook webhook, w http.ResponseWriter, r *http.Request) {
+	err := json.NewEncoder(w).Encode(hook.SwitchStates)
+
+	if err != nil {
+		log.Printf("Failed to send response: %v", err)
+		return
+	}
+
+	// momentary switches have been read, so make sure they're 0
+	// next time
+	for _, i := range hook.MomentarySwitches {
+		hook.SwitchStates[i] = 0
+	}
+}
+
+func webhookWrite(hook webhook, w http.ResponseWriter, r *http.Request) {
+	err := json.NewDecoder(r.Body).Decode(&hook.SwitchStates)
+	if err != nil {
+		log.Printf("Failed to parse json for '%s': %v", hook.Name, err)
+		http.Error(w, "Failed to parse json", http.StatusBadRequest)
+		return
+	}
+}
+
+func main() {
+	// read environment config
+	viper.BindEnv("Debug", "DEBUG")
+	viper.BindEnv("WebhookFile", "WEBHOOK_CONFIG_FILE")
+	viper.BindEnv("ListenPort", "PORT")
+
+	viper.SetDefault("ListenPort", "7200")
+	viper.SetDefault("WebhookFile", "./webhooks.yaml")
+	viper.SetDefault("Debug", false)
+
+	// read webhook config
+	initWebhooks(viper.GetString("WebhookFile"))
+
+	// serve app
+	runServer()
+}