initial code commit

batched-server/main.go

@@ -0,0 +1,111 @@
+package main
+
+import (
+	"encoding/csv"
+	"encoding/json"
+	"net/http"
+	"os"
+	"strings"
+	"sync"
+	"time"
+)
+
+const PORT = ":3000"
+
+var (
+	emailQueue []string
+	queueLock  sync.Mutex
+)
+
+
+func saveEmails() {
+	queueLock.Lock()
+	defer queueLock.Unlock()
+
+	if len(emailQueue) == 0 {
+		return
+	}
+
+	fileExists := true
+	if _, err := os.Stat("emails.csv"); os.IsNotExist(err) {
+		fileExists = false
+	}
+
+	f, err := os.OpenFile("emails.csv", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+
+	writer := csv.NewWriter(f)
+	defer writer.Flush()
+
+	// write header if file is new
+	if !fileExists {
+		if err := writer.Write([]string{"email", "timestamp"}); err != nil {
+			return
+		}
+	}
+
+	// write each email with timestamp
+	for _, email := range emailQueue {
+		timestamp := time.Now().Format(time.RFC3339)
+		if err := writer.Write([]string{email, timestamp}); err != nil {
+			return
+		}
+	}
+
+	// clear queue
+	emailQueue = emailQueue[:0]
+}
+
+// background goroutine to batch writes
+func init() {
+	go func() {
+		for {
+			time.Sleep(5 * time.Second);
+			queueLock.Lock();
+			hasEmails := len(emailQueue) > 0;
+			queueLock.Unlock();
+			if hasEmails {
+				saveEmails();
+			}
+		}
+	}();	
+}
+
+
+func submitHandler(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "POST" {
+		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	email := strings.TrimSpace(r.FormValue("email"))
+	if email == "" {
+		http.Error(w, "Email required", http.StatusBadRequest)
+		return
+	}
+
+	queueLock.Lock()
+	emailQueue = append(emailQueue, email)
+	shouldFlush := len(emailQueue) >= 100
+	queueLock.Unlock()
+
+	if shouldFlush {
+		saveEmails()
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(map[string]string{"message": "data received"})
+}
+
+
+func main() {
+	http.HandleFunc("/submit", submitHandler)
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte("Batched Write Server is running"))
+	})
+	http.ListenAndServe(PORT, nil)
+}