golifehk/datasources/mtr/bus/busschedule.go

147 lines
3.4 KiB
Go

package bus
import (
"fmt"
"bytes"
"encoding/json"
"io"
"log"
"net/http"
"path/filepath"
"time"
"github.com/tgckpg/golifehk/utils"
)
type Location struct {
latitude float32
longitude float32
}
type Bus struct {
ETA int `json:"arrivalTimeInSecond,string"`
ETAText string `json:"arrivalTimeText"`
BusId string `json:"busId"`
BusLocation Location `json:"busLocation"`
ETD string `json:"departureTimeInSecond"`
ETDText string `json:"departureTimeText"`
Delayed string `json:"isDelayed"`
Scheduled string `json:"isScheduled"`
LineRef string `json:"lineRef"`
}
type BusStopBuses struct {
Buses [] Bus `json:"bus"`
BusStopId string `json:"busStopId"`
Suspended string `json:"isSuspended"`
}
type ScheduleStatusTime struct {
time.Time
}
type BusSchedule struct {
RefreshTime int `json:"appRefreshTimeInSecond,string"`
BusStops [] BusStopBuses `json:"busStop"`
StatusTime ScheduleStatusTime `json:"routeStatusTime"`
RemarksTitle string `json:"routeStatusRemarkTitle"`
// 0 = OK
// 100 = Rate limit ( Unconfirmed. Not in spec )
Status int `json:"status,string"`
}
func (t *ScheduleStatusTime) UnmarshalJSON(b []byte) (err error) {
date, err := time.Parse(`"2006\/01\/02 15:04"`, string(b))
if err != nil {
return err
}
t.Time = date
return
}
func getSchedule( lang string, routeName string ) ( *BusSchedule, error ) {
CACHE_PATH := filepath.Join(
utils.WORKDIR,
"mtr_bsch" + "-" + lang + "-" + routeName + ".json",
)
postLang := "en"
if lang == "zh-Hant" {
postLang = "zh"
}
QUERY_FUNC := func() ( io.ReadCloser, error ) {
// Query Remote
values := map[string]string { "language": postLang, "routeName": routeName }
jsonValue, _ := json.Marshal(values)
resp, err := http.Post(
"https://rt.data.gov.hk/v1/transport/mtr/bus/getSchedule",
"application/json",
bytes.NewBuffer( jsonValue ),
)
if err != nil {
return nil, err
}
return resp.Body, nil
}
cs, err := utils.CacheStreamEx( CACHE_PATH, QUERY_FUNC )
if err != nil {
return nil, err
}
oldSch := BusSchedule{
Status: -1,
}
if cs.Local != nil {
err = json.Unmarshal( cs.Local.Bytes(), &oldSch )
if err != nil {
return nil, err
}
}
newSch := BusSchedule{
Status: -1,
}
for i := 0; i < 3; i ++ {
if cs.Remote != nil {
err = json.Unmarshal( cs.Remote.Bytes(), &newSch )
if err != nil {
return nil, err
}
}
if newSch.Status == 0 {
cs.Commit()
return &newSch, nil
}
if oldSch.Status == 0 {
if cs.NotExpired( 60 ) || oldSch.StatusTime.Time == newSch.StatusTime.Time {
log.Printf( "Using cache: %s", CACHE_PATH )
return &oldSch, nil
}
}
// First time + try again i times
err = cs.Reload()
log.Printf( "Reloading (%d): %s", i, CACHE_PATH )
if err != nil {
err = fmt.Errorf( "Error retrieving data: %s", err )
return nil, err
}
}
if newSch.Status != 0 {
err = fmt.Errorf( "%s (%d)", newSch.RemarksTitle, newSch.Status )
}
return &newSch, err
}