Generalize cache get with expire param

datasources/mtr/bus/busschedule.go

@@ -0,0 +1,76 @@
+package bus
+
+import (
+    "bytes"
+    "encoding/json"
+    "io"
+    "net/http"
+    "path/filepath"
+
+    "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 BusStopSchedules struct {
+    Buses [] Bus `json:"bus"`
+    Suspended string `json:"isSuspended"`
+}
+
+type BusSchedule struct {
+    RefreshTime int `json:"appRefreshTimeInSecond,string"`
+    BusStops [] BusStopSchedules `json:"busStop"`
+}
+
+func getSchedule( lang string, routeName string ) ( *BusSchedule, error ) {
+
+    CACHE_PATH := filepath.Join(
+        utils.WORKDIR,
+        "mtr_bsch" + "-" + lang + "-" + routeName + ".json",
+    )
+
+    QUERY_FUNC := func() ( io.ReadCloser, error ) {
+        // Query Remote
+        values := map[string]string { "language": lang , "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
+    }
+
+    buff, err := utils.CacheStream( CACHE_PATH, QUERY_FUNC, 60 )
+    if err != nil {
+        return nil, err
+    }
+
+    schedules := BusSchedule{}
+    err = json.Unmarshal( buff.Bytes(), &schedules )
+    if err != nil {
+        return nil, err
+    }
+
+    return &schedules, nil
+}