webapp

internal/api/middleware/pagination.go

@@ -0,0 +1,48 @@
+package middleware
+
+import (
+	"context"
+	"net/http"
+	"strconv"
+)
+
+type Pagination struct {
+	Page     int
+	PageSize int
+}
+
+const PaginationContextKey = "pagination"
+
+func PaginationMiddleware() func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			page := 1
+			pageSize := 20
+
+			if p := r.URL.Query().Get("page"); p != "" {
+				if parsed, err := strconv.Atoi(p); err == nil && parsed >= 1 {
+					page = parsed
+				}
+			}
+
+			if ps := r.URL.Query().Get("page_size"); ps != "" {
+				if parsed, err := strconv.Atoi(ps); err == nil && parsed >= 1 {
+					pageSize = parsed
+				}
+			}
+
+			if pageSize > 100 {
+				pageSize = 100
+			}
+
+			ctx := context.WithValue(r.Context(), PaginationContextKey, Pagination{
+				Page:     page,
+				PageSize: pageSize,
+			})
+
+			next.ServeHTTP(w, r.WithContext(ctx))
+		}
+
+		return http.HandlerFunc(fn)
+	}
+}