feat: initpage com sync Go + auth + frontend em web/

internal/sync/sync.go

@@ -0,0 +1,91 @@
+package sync
+
+import (
+	"database/sql"
+	"encoding/json"
+	"net/http"
+	"time"
+
+	mw "github.com/weltonmoura/initpage/internal/middleware"
+)
+
+type Sync struct {
+	DB *sql.DB
+}
+
+type syncPayload struct {
+	Data    json.RawMessage `json:"data"`
+	Version int             `json:"version"`
+}
+
+func (s *Sync) Get(w http.ResponseWriter, r *http.Request) {
+	uid := mw.GetUserID(r.Context())
+	if uid == "" {
+		w.WriteHeader(http.StatusUnauthorized)
+		return
+	}
+	var data string
+	var version int
+	var updatedAt string
+	_ = s.DB.QueryRow(`SELECT data, version, updated_at FROM user_sync WHERE user_id=?`, uid).Scan(&data, &version, &updatedAt)
+	if data == "" {
+		w.Header().Set("Content-Type", "application/json")
+		w.Write([]byte(`{"data":null,"version":0}`))
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+	w.Write([]byte(`{"data":` + data + `,"version":` + itoa(version) + `}`))
+}
+
+func (s *Sync) Put(w http.ResponseWriter, r *http.Request) {
+	uid := mw.GetUserID(r.Context())
+	if uid == "" {
+		w.WriteHeader(http.StatusUnauthorized)
+		return
+	}
+	var p syncPayload
+	if err := json.NewDecoder(r.Body).Decode(&p); err != nil {
+		w.WriteHeader(http.StatusBadRequest)
+		w.Write([]byte(`{"error":"json inválido"}`))
+		return
+	}
+	if len(p.Data) > 256*1024 {
+		w.WriteHeader(http.StatusBadRequest)
+		w.Write([]byte(`{"error":"dados muito grandes"}`))
+		return
+	}
+	// valida JSON básico
+	if !json.Valid(p.Data) {
+		w.WriteHeader(http.StatusBadRequest)
+		w.Write([]byte(`{"error":"json inválido"}`))
+		return
+	}
+	_, err := s.DB.Exec(`INSERT INTO user_sync(user_id,data,version,updated_at) VALUES(?,?,?,?)
+		ON CONFLICT(user_id) DO UPDATE SET data=excluded.data, version=excluded.version, updated_at=excluded.updated_at`,
+		uid, string(p.Data), p.Version, time.Now())
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+	w.Write([]byte(`{"ok":true}`))
+}
+
+func itoa(i int) string {
+	if i == 0 {
+		return "0"
+	}
+	sign := ""
+	if i < 0 {
+		sign = "-"
+		i = -i
+	}
+	b := [12]byte{}
+	n := len(b)
+	for i > 0 {
+		n--
+		b[n] = byte('0' + i%10)
+		i /= 10
+	}
+	return sign + string(b[n:])
+}