Daheimladen: reduce api requests by adding cache

charger/daheimladen.go

@@ -4,9 +4,11 @@ import (
 	"fmt"
 	"net/http"
 	"strconv"
+	"time"
 
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/charger/daheimladen"
+	"github.com/evcc-io/evcc/provider"
 	"github.com/evcc-io/evcc/util"
 	"github.com/evcc-io/evcc/util/request"
 	"golang.org/x/oauth2"
@@ -20,6 +22,9 @@ type DaheimLaden struct {
 	idTag         string
 	token         string
 	transactionID int32
+	statusG       func() (daheimladen.GetLatestStatus, error)
+	meterG        func() (daheimladen.GetLatestMeterValueResponse, error)
+	cache         time.Duration
 }
 
 func init() {
@@ -28,26 +33,30 @@ func init() {
 
 // NewDaheimLadenFromConfig creates a DaheimLaden charger from generic config
 func NewDaheimLadenFromConfig(other map[string]interface{}) (api.Charger, error) {
-	var cc struct {
+	cc := struct {
 		Token     string
 		StationID string
+		Cache     time.Duration
+	}{
+		Cache: time.Second,
 	}
 
 	if err := util.DecodeOther(other, &cc); err != nil {
 		return nil, err
 	}
 
-	return NewDaheimLaden(cc.Token, cc.StationID)
+	return NewDaheimLaden(cc.Token, cc.StationID, cc.Cache)
 }
 
 // NewDaheimLaden creates DaheimLaden charger
-func NewDaheimLaden(token, stationID string) (*DaheimLaden, error) {
+func NewDaheimLaden(token, stationID string, cache time.Duration) (*DaheimLaden, error) {
 	c := &DaheimLaden{
 		Helper:      request.NewHelper(util.NewLogger("daheim")),
 		stationID:   stationID,
 		connectorID: 1,
 		idTag:       daheimladen.EVCC_IDTAG,
 		token:       token,
+		cache:       cache,
 	}
 
 	c.Client.Transport = &oauth2.Transport{
@@ -57,18 +66,59 @@ func NewDaheimLaden(token, stationID string) (*DaheimLaden, error) {
 		}),
 		Base: c.Client.Transport,
 	}
+
+	c.reset()
+
 	return c, nil
 }
 
+// reset cache
+func (c *DaheimLaden) reset() {
+	c.statusG = provider.Cached(func() (daheimladen.GetLatestStatus, error) {
+		var res daheimladen.GetLatestStatus
+		err := c.GetJSON(fmt.Sprintf("%s/cs/%s/status", daheimladen.BASE_URL, c.stationID), &res)
+		return res, err
+	}, c.cache)
+
+	c.meterG = provider.Cached(func() (daheimladen.GetLatestMeterValueResponse, error) {
+		var res daheimladen.GetLatestMeterValueResponse
+		err := c.GetJSON(fmt.Sprintf("%s/cs/%s/metervalue", daheimladen.BASE_URL, c.stationID), &res)
+		return res, err
+	}, c.cache)
+}
+
+// Status implements the api.Charger interface
+func (c *DaheimLaden) Status() (api.ChargeStatus, error) {
+	res, err := c.statusG()
+	if err != nil {
+		return api.StatusNone, err
+	}
+
+	status := daheimladen.ChargePointStatus(res.Status)
+	switch status {
+	case daheimladen.AVAILABLE:
+		return api.StatusA, nil
+	case daheimladen.PREPARING:
+		return api.StatusB, nil
+	case daheimladen.CHARGING, daheimladen.FINISHING:
+		return api.StatusC, nil
+	case daheimladen.FAULTED:
+		return api.StatusF, nil
+	default:
+		return api.StatusNone, fmt.Errorf("invalid status: %s", res.Status)
+	}
+}
+
 // Enabled implements the api.Charger interface
 func (c *DaheimLaden) Enabled() (bool, error) {
-	var res daheimladen.GetLatestStatus
-	err := c.GetJSON(fmt.Sprintf("%s/cs/%s/status", daheimladen.BASE_URL, c.stationID), &res)
+	res, err := c.statusG()
 	return res.Status == string(daheimladen.CHARGING), err
 }
 
 // Enable implements the api.Charger interface
 func (c *DaheimLaden) Enable(enable bool) error {
+	defer c.reset()
+
 	if enable {
 		data := daheimladen.RemoteStartRequest{
 			ConnectorID: c.connectorID,
@@ -117,6 +167,8 @@ func (c *DaheimLaden) Enable(enable bool) error {
 
 // MaxCurrent implements the api.Charger interface
 func (c *DaheimLaden) MaxCurrent(current int64) error {
+	defer c.reset()
+
 	data := daheimladen.ChangeConfigurationRequest{
 		Key:   string(daheimladen.CHARGE_RATE),
 		Value: strconv.FormatInt(current, 10),
@@ -136,55 +188,26 @@ func (c *DaheimLaden) MaxCurrent(current int64) error {
 	return err
 }
 
-// Status implements the api.Charger interface
-func (c *DaheimLaden) Status() (api.ChargeStatus, error) {
-	var res daheimladen.GetLatestStatus
-	uri := fmt.Sprintf("%s/cs/%s/status", daheimladen.BASE_URL, c.stationID)
-	if err := c.GetJSON(uri, &res); err != nil {
-		return api.StatusNone, err
-	}
-
-	status := daheimladen.ChargePointStatus(res.Status)
-	switch status {
-	case daheimladen.AVAILABLE:
-		return api.StatusA, nil
-	case daheimladen.PREPARING:
-		return api.StatusB, nil
-	case daheimladen.CHARGING, daheimladen.FINISHING:
-		return api.StatusC, nil
-	case daheimladen.FAULTED:
-		return api.StatusF, nil
-	default:
-		return api.StatusNone, fmt.Errorf("invalid status: %s", res.Status)
-	}
-}
-
 var _ api.Meter = (*DaheimLaden)(nil)
 
 // CurrentPower implements the api.Meter interface
 func (c *DaheimLaden) CurrentPower() (float64, error) {
-	var res daheimladen.GetLatestMeterValueResponse
-	uri := fmt.Sprintf("%s/cs/%s/metervalue", daheimladen.BASE_URL, c.stationID)
-	err := c.GetJSON(uri, &res)
+	res, err := c.meterG()
 	return float64(res.ActivePowerImport * 1e3), err
 }
 
 var _ api.MeterEnergy = (*DaheimLaden)(nil)
 
 // TotalEnergy implements the api.MeterMeterEnergy interface
 func (c *DaheimLaden) TotalEnergy() (float64, error) {
-	var res daheimladen.GetLatestMeterValueResponse
-	uri := fmt.Sprintf("%s/cs/%s/metervalue", daheimladen.BASE_URL, c.stationID)
-	err := c.GetJSON(uri, &res)
+	res, err := c.meterG()
 	return float64(res.EnergyActiveImportRegister), err
 }
 
 var _ api.MeterCurrent = (*DaheimLaden)(nil)
 
 // Currents implements the api.MeterCurrent interface
 func (c *DaheimLaden) Currents() (float64, float64, float64, error) {
-	var res daheimladen.GetLatestMeterValueResponse
-	uri := fmt.Sprintf("%s/cs/%s/metervalue", daheimladen.BASE_URL, c.stationID)
-	err := c.GetJSON(uri, &res)
+	res, err := c.meterG()
 	return float64(res.CurrentImportPhaseL1), float64(res.CurrentImportPhaseL2), float64(res.CurrentImportPhaseL3), err
 }