holiday-api/handlers.go

package main

import (
	"encoding/xml"
	"fmt"
	"github.com/google/uuid"
	"holiday-api/holiday"
	"log"
	"net/http"
	"strconv"
	"time"
)

func getHolidays(service holiday.Service) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			log.Printf("Failed parsing params: %v", err)
		}
		paging := holiday.Paging{
			PageSize: readInt(r, "pageSize", 1000),
			Page:     readInt(r, "page", 0),
		}
		search := holiday.Search{
			Country:          r.Form.Get("country"),
			Year:             readIntNullable(r, "year"),
			Date:             readDateNullable(r, "date"),
			RangeStart:       readDateNullable(r, "rangeStart"),
			RangeEnd:         readDateNullable(r, "rangeEnd"),
			StateHoliday:     readBoolNullable(r, "stateHoliday"),
			ReligiousHoliday: readBoolNullable(r, "religiousHoliday"),
		}
		holidays, err := service.Find(search, paging)
		if err != nil {
			render(w, r, 404, ErrorResponse{Created: time.Now(), Message: "failed fetching holidays"})
		} else {
			render(w, r, 200, mapHolidays(holidays))
		}
	}
}

type DateResponse struct{ time.Time }

func (d DateResponse) MarshalJSON() ([]byte, error) {
	return []byte("\"" + d.String() + "\""), nil
}
func (d DateResponse) String() string {
	return fmt.Sprintf(`%04d-%02d-%02d`, d.Year(), d.Month(), d.Day())
}

type ErrorResponse struct {
	XMLName xml.Name  `json:"-" xml:"Error"`
	Created time.Time `json:"created" xml:"created"`
	Message string    `json:"message" xml:"message"`
	Code    int       `json:"-" xml:"-"`
}

type HolidayResponse struct {
	XMLName  xml.Name              `json:"-" xml:"Holidays"`
	Holidays []HolidayItemResponse `json:"holidays"`
}

type HolidayItemResponse struct {
	XMLName            xml.Name     `json:"-" xml:"Holiday"`
	Id                 uuid.UUID    `json:"id" xml:"id,attr"`
	Date               DateResponse `json:"date" xml:"date,attr"`
	Name               string       `json:"name" xml:"name"`
	Description        string       `json:"description" xml:"description,omitempty"`
	IsStateHoliday     bool         `json:"isStateHoliday" xml:"isState,attr"`
	IsReligiousHoliday bool         `json:"isReligiousHoliday" xml:"isReligious,attr"`
}

type HolidaySingleResponse struct {
	Id                 *uuid.UUID
	Country            string
	Date               DateResponse
	Name               string
	Description        string
	IsStateHoliday     bool
	IsReligiousHoliday bool
}

type HolidaySingleRequest struct {
	Id                 *uuid.UUID
	Country            string
	Date               DateResponse
	Name               string
	Description        string
	IsStateHoliday     bool
	IsReligiousHoliday bool
}

func mapHolidays(holidays []holiday.Holiday) HolidayResponse {
	var response = make([]HolidayItemResponse, 0, len(holidays))
	for _, h := range holidays {
		response = append(response, HolidayItemResponse{
			Id:                 h.Id,
			Date:               DateResponse{h.Date},
			Name:               h.Name,
			Description:        h.Description,
			IsStateHoliday:     h.IsStateHoliday,
			IsReligiousHoliday: h.IsReligiousHoliday,
		})
	}
	return HolidayResponse{
		Holidays: response,
	}
}

func readDateNullable(r *http.Request, param string) *time.Time {
	if r.Form.Has(param) {
		var year, month, date int
		count, err := fmt.Sscanf(r.Form.Get(param), "%d-%d-%d", &year, &month, &date)
		if count < 3 {
			log.Printf("failed reading %s: %v", param, err)
			return nil
		} else {
			readDate := time.Date(year, time.Month(month), date, 0, 0, 0, 0, time.UTC)
			return &readDate
		}
	} else {
		return nil
	}
}

func readIntNullable(r *http.Request, param string) *int {
	if r.Form.Has(param) {
		if value, err := strconv.Atoi(r.Form.Get(param)); err == nil {
			return &value
		} else {
			return nil
		}
	} else {
		return nil
	}
}

func readBoolNullable(r *http.Request, param string) *bool {
	if r.Form.Has(param) {
		if value, err := strconv.ParseBool(r.Form.Get(param)); err == nil {
			return &value
		} else {
			return nil
		}
	} else {
		return nil
	}
}

func readInt(r *http.Request, param string, defaultValue int) int {
	if r.Form.Has(param) {
		if value, err := strconv.Atoi(r.Form.Get(param)); err == nil {
			return value
		} else {
			return defaultValue
		}
	} else {
		return defaultValue
	}
}