appcore/request/query.go

// Copyright 2024 Patial Tech (Ankit Patial).
//
// This file is part of code.patial.tech/go/appcore, which is MIT licensed.
// See http://opensource.org/licenses/MIT

package request

import (
	"fmt"
	"net/http"
	"reflect"
	"strconv"
)

type Number interface {
	int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64 | float32 | float64
}

// NumberParam from request query string
func NumberParam[T Number](r *http.Request, key string) (T, error) {
	var noop T
	q := r.URL.Query()
	if !q.Has(key) {
		return noop, fmt.Errorf("query param: %q is missing", key)
	}

	p := q.Get(key)
	k := reflect.TypeOf(noop).Kind()
	// float param
	if k == reflect.Float32 || k == reflect.Float64 {
		n, err := strconv.ParseFloat(p, 64)
		if err != nil {
			return noop, fmt.Errorf("query param: %q is not a valid float", key)
		}
		return T(n), nil
	}

	// unsigned int param
	if k >= reflect.Uint && k <= reflect.Uint64 {
		n, err := strconv.ParseUint(p, 10, 64)
		if err != nil {
			return noop, fmt.Errorf("query param: %q is not a valid unsigned integer", key)
		}

		return T(n), nil
	}

	// signed int param
	n, err := strconv.ParseInt(p, 10, 64)
	if err != nil {
		return noop, fmt.Errorf("query param: %q is not a valid integer", key)
	}

	return T(n), nil
}