backend/internal/httpapi/json.go - master - DexScen/ProjectPOH

backend/internal/httpapi/json.go
91 строка2 KB
Александр
initial prototype ready
29 апр 2026, 06:02
29 апр 2026, 06:027af145a
package httpapi

import (
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strconv"
	"strings"
)

type ErrorResponse struct {
	Error string `json:"error"`
}

func WriteJSON(w http.ResponseWriter, status int, payload any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	if payload == nil {
		return
	}

	_ = json.NewEncoder(w).Encode(payload)
}

func WriteError(w http.ResponseWriter, status int, err error) {
	if err == nil {
		WriteJSON(w, status, ErrorResponse{Error: http.StatusText(status)})
		return
	}
	WriteJSON(w, status, ErrorResponse{Error: err.Error()})
}

func ReadJSON(r *http.Request, dst any) error {
	defer r.Body.Close()
	dec := json.NewDecoder(io.LimitReader(r.Body, 1<<20))
	dec.DisallowUnknownFields()

	if err := dec.Decode(dst); err != nil {
		if errors.Is(err, io.EOF) {
			return errors.New("request body is required")
		}
		return fmt.Errorf("invalid JSON: %w", err)
	}

	if dec.More() {
		return errors.New("request body must contain a single JSON object")
	}

	return nil
}

func ParsePositiveInt64(raw, field string) (int64, error) {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		return 0, fmt.Errorf("%s is required", field)
	}

	v, err := strconv.ParseInt(raw, 10, 64)
	if err != nil || v <= 0 {
		return 0, fmt.Errorf("%s must be a positive integer", field)
	}
	return v, nil
}

func ParsePagination(r *http.Request, defaultLimit, maxLimit int) (limit int, offset int, err error) {
	limit = defaultLimit
	offset = 0

	if raw := strings.TrimSpace(r.URL.Query().Get("limit")); raw != "" {
		v, parseErr := strconv.Atoi(raw)
		if parseErr != nil || v <= 0 {
			return 0, 0, errors.New("limit must be a positive integer")
		}
		if v > maxLimit {
			v = maxLimit
		}
		limit = v
	}

	if raw := strings.TrimSpace(r.URL.Query().Get("offset")); raw != "" {
		v, parseErr := strconv.Atoi(raw)
		if parseErr != nil || v < 0 {
			return 0, 0, errors.New("offset must be a non-negative integer")
		}
		offset = v
	}

	return limit, offset, nil
}