Make sidewalk slice concurrency-safe

main.go

@@ -11,6 +11,7 @@ import (
 	"net/http"
 	"runtime/debug"
 	"strconv"
+	"sync"
 	"time"
 
 	"git.chandlerswift.com/chandlerswift/nau-sidewalks/sidewalk"
@@ -42,6 +43,7 @@ func main() {
 
 	// Decode the JSON data
 	var sidewalks []sidewalk.Sidewalk
+	var sidewalksMutex sync.RWMutex
 	if err := json.Unmarshal(sidewalk_data, &sidewalks); err != nil {
 		log.Fatalf("Error decoding JSON: %v", err)
 	}
@@ -58,7 +60,9 @@ func main() {
 
 	http.HandleFunc("GET /api/sidewalks", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
+		sidewalksMutex.RLock()
 		json.NewEncoder(w).Encode(sidewalks)
+		sidewalksMutex.RUnlock()
 	})
 
 	http.HandleFunc("POST /api/sidewalks/{id}", func(w http.ResponseWriter, r *http.Request) {
@@ -75,8 +79,10 @@ func main() {
 		if err != nil {
 			http.Error(w, "Invalid condition", http.StatusBadRequest)
 		}
+		sidewalksMutex.Lock()
 		sidewalks[sidewalkID].Condition = sidewalk.Condition(condition)
 		sidewalks[sidewalkID].LastUpdated = time.Now()
+		sidewalksMutex.Unlock()
 		http.Redirect(w, r, "/", http.StatusSeeOther)
 	})