Add HTTP provider

README.md

@@ -35,6 +35,7 @@ EVCC is an extensible EV Charge Controller with PV integration implemented in [G
   - [Modbus](#modbus-read-only)
   - [MQTT](#mqtt-readwrite)
   - [Script](#script-readwrite)
+  - [HTTP](#http-readwrite)
   - [Combined status](#combined-status-read-only)
 - [Developer](#developer)
 - [Background](#background)
@@ -320,6 +321,28 @@ cmd: /home/user/my-script.sh ${enable:%b} # format boolean enable as 0/1
 timeout: 5s
 ```
 
+### HTTP (read/write)
+
+The `http` plugin executes HTTP requests to read or update data. Includes the ability to read and parse JSON using jq-like queries.
+
+Sample read configuration:
+
+```yaml
+type: http
+uri: https://volkszaehler/api/data/<uuid>.json?from=now
+method: GET # default HTTP method
+headers:
+- content-type: application/json
+jq: .data.tuples.[0].[1] # parse response json
+```
+
+Sample write configuration:
+
+```yaml
+...
+body: %v # only applicable for PUT or POST requests
+```
+
 ### Combined status (read only)
 
 The `combined` status plugin is used to convert a mixed boolean status of plugged/charging into an EVCC-compatible charger status of A..F. It is typically used together with OpenWB MQTT integration.

go.mod

@@ -15,6 +15,7 @@ require (
 	github.com/gregdel/pushover v0.0.0-20200330145937-ee607c681498
 	github.com/grid-x/modbus v0.0.0-20200108122021-57d05a9f1e1a
 	github.com/influxdata/influxdb1-client v0.0.0-20191209144304-8bf82d3c094d
+	github.com/itchyny/gojq v0.10.1
 	github.com/joeshaw/carwings v0.0.0-20191118152321-61b46581307a
 	github.com/jsgoecke/tesla v0.0.0-20190206234002-112508e1374e
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51

provider/config.go

@@ -63,6 +63,8 @@ func scriptFromConfig(log *util.Logger, other map[string]interface{}) scriptConf
 // NewFloatGetterFromConfig creates a FloatGetter from config
 func NewFloatGetterFromConfig(log *util.Logger, config Config) (res FloatGetter) {
 	switch strings.ToLower(config.Type) {
+	case "http":
+		res = NewHTTPProviderFromConfig(log, config.Other).FloatGetter
 	case "mqtt":
 		pc := mqttFromConfig(log, config.Other)
 		res = MQTT.FloatGetter(pc.Topic, pc.Multiplier, pc.Timeout)
@@ -84,6 +86,8 @@ func NewFloatGetterFromConfig(log *util.Logger, config Config) (res FloatGetter)
 // NewIntGetterFromConfig creates a IntGetter from config
 func NewIntGetterFromConfig(log *util.Logger, config Config) (res IntGetter) {
 	switch strings.ToLower(config.Type) {
+	case "http":
+		res = NewHTTPProviderFromConfig(log, config.Other).IntGetter
 	case "mqtt":
 		pc := mqttFromConfig(log, config.Other)
 		res = MQTT.IntGetter(pc.Topic, int64(pc.Multiplier), pc.Timeout)
@@ -105,6 +109,8 @@ func NewIntGetterFromConfig(log *util.Logger, config Config) (res IntGetter) {
 // NewStringGetterFromConfig creates a StringGetter from config
 func NewStringGetterFromConfig(log *util.Logger, config Config) (res StringGetter) {
 	switch strings.ToLower(config.Type) {
+	case "http":
+		res = NewHTTPProviderFromConfig(log, config.Other).StringGetter
 	case "mqtt":
 		pc := mqttFromConfig(log, config.Other)
 		res = MQTT.StringGetter(pc.Topic, pc.Timeout)
@@ -126,6 +132,8 @@ func NewStringGetterFromConfig(log *util.Logger, config Config) (res StringGette
 // NewBoolGetterFromConfig creates a BoolGetter from config
 func NewBoolGetterFromConfig(log *util.Logger, config Config) (res BoolGetter) {
 	switch strings.ToLower(config.Type) {
+	case "http":
+		res = NewHTTPProviderFromConfig(log, config.Other).BoolGetter
 	case "mqtt":
 		pc := mqttFromConfig(log, config.Other)
 		res = MQTT.BoolGetter(pc.Topic, pc.Timeout)
@@ -145,13 +153,15 @@ func NewBoolGetterFromConfig(log *util.Logger, config Config) (res BoolGetter) {
 // NewIntSetterFromConfig creates a IntSetter from config
 func NewIntSetterFromConfig(log *util.Logger, param string, config Config) (res IntSetter) {
 	switch strings.ToLower(config.Type) {
+	case "http":
+		res = NewHTTPProviderFromConfig(log, config.Other).IntSetter
 	case "mqtt":
 		pc := mqttFromConfig(log, config.Other)
 		res = MQTT.IntSetter(param, pc.Topic, pc.Payload)
 	case "script":
 		pc := scriptFromConfig(log, config.Other)
-		exec := NewScriptProvider(pc.Timeout)
-		res = exec.IntSetter(param, pc.Cmd)
+		script := NewScriptProvider(pc.Timeout)
+		res = script.IntSetter(param, pc.Cmd)
 	default:
 		log.FATAL.Fatalf("invalid setter type %s", config.Type)
 	}
@@ -161,13 +171,15 @@ func NewIntSetterFromConfig(log *util.Logger, param string, config Config) (res
 // NewBoolSetterFromConfig creates a BoolSetter from config
 func NewBoolSetterFromConfig(log *util.Logger, param string, config Config) (res BoolSetter) {
 	switch strings.ToLower(config.Type) {
+	case "http":
+		res = NewHTTPProviderFromConfig(log, config.Other).BoolSetter
 	case "mqtt":
 		pc := mqttFromConfig(log, config.Other)
 		res = MQTT.BoolSetter(param, pc.Topic, pc.Payload)
 	case "script":
 		pc := scriptFromConfig(log, config.Other)
-		exec := NewScriptProvider(pc.Timeout)
-		res = exec.BoolSetter(param, pc.Cmd)
+		script := NewScriptProvider(pc.Timeout)
+		res = script.BoolSetter(param, pc.Cmd)
 	default:
 		log.FATAL.Fatalf("invalid setter type %s", config.Type)
 	}

provider/http.go

@@ -0,0 +1,142 @@
+package provider
+
+import (
+	"fmt"
+	"io"
+	"math"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/andig/evcc/util"
+	"github.com/andig/evcc/util/jq"
+	"github.com/itchyny/gojq"
+)
+
+// HTTP implements HTTP request provider
+type HTTP struct {
+	log *util.Logger
+	*util.HTTPHelper
+	url, method string
+	headers     map[string]string
+	body        string
+	scale       float64
+	jq          *gojq.Query
+}
+
+// NewHTTPProviderFromConfig creates a HTTP provider
+func NewHTTPProviderFromConfig(log *util.Logger, other map[string]interface{}) *HTTP {
+	cc := struct {
+		URI, Method string
+		Headers     map[string]string
+		Body        string
+		Jq          string
+		Scale       float64
+	}{}
+	util.DecodeOther(log, other, &cc)
+
+	logger := util.NewLogger("http")
+
+	p := &HTTP{
+		log:        logger,
+		HTTPHelper: util.NewHTTPHelper(logger),
+		url:        cc.URI,
+		method:     cc.Method,
+		headers:    cc.Headers,
+		body:       cc.Body,
+		scale:      cc.Scale,
+	}
+
+	if cc.Jq != "" {
+		op, err := gojq.Parse(cc.Jq)
+		if err != nil {
+			log.FATAL.Fatalf("config: invalid jq query: %s", p.jq)
+		}
+
+		p.jq = op
+	}
+
+	return p
+}
+
+// request executed the configured request
+func (p *HTTP) request(body ...string) ([]byte, error) {
+	var b io.Reader
+	if len(body) == 1 {
+		b = strings.NewReader(body[0])
+	}
+
+	// empty method becomes GET
+	req, err := http.NewRequest(strings.ToUpper(p.method), p.url, b)
+	if err == nil {
+		for k, v := range p.headers {
+			req.Header.Add(k, v)
+		}
+		return p.Request(req)
+	}
+
+	return []byte{}, err
+}
+
+// FloatGetter parses float from request
+func (p *HTTP) FloatGetter() (float64, error) {
+	s, err := p.StringGetter()
+	if err != nil {
+		return 0, err
+	}
+
+	f, err := strconv.ParseFloat(s, 64)
+	if err == nil && p.scale > 0 {
+		f *= p.scale
+	}
+
+	return f, err
+}
+
+// IntGetter parses int64 from request
+func (p *HTTP) IntGetter() (int64, error) {
+	f, err := p.FloatGetter()
+	return int64(math.Round(f)), err
+}
+
+// StringGetter sends string request
+func (p *HTTP) StringGetter() (string, error) {
+	b, err := p.request()
+	if err != nil {
+		return string(b), err
+	}
+
+	if p.jq != nil {
+		v, err := jq.Query(p.jq, b)
+		return fmt.Sprintf("%v", v), err
+	}
+
+	return string(b), err
+}
+
+// BoolGetter parses bool from request
+func (p *HTTP) BoolGetter() (bool, error) {
+	s, err := p.StringGetter()
+	return util.Truish(s), err
+}
+
+// IntSetter sends int request
+func (p *HTTP) IntSetter(param int64) error {
+	body := util.FormatValue(p.body, param)
+	_, err := p.request(body)
+	return err
+}
+
+// StringSetter sends string request
+func (p *HTTP) StringSetter(param string) error {
+	body := util.FormatValue(p.body, param)
+	_, err := p.request(body)
+	return err
+}
+
+// BoolSetter sends bool request
+func (p *HTTP) BoolSetter(param bool) error {
+	body := util.FormatValue(p.body, param)
+	_, err := p.request(body)
+	return err
+}

util/jq/jq.go

@@ -0,0 +1,33 @@
+package jq
+
+import (
+	"encoding/json"
+
+	"github.com/itchyny/gojq"
+	"github.com/pkg/errors"
+)
+
+// Query executes a compiled jq query against given input. It expects a single result only.
+func Query(query *gojq.Query, input []byte) (interface{}, error) {
+	var j interface{}
+	if err := json.Unmarshal(input, &j); err != nil {
+		return j, err
+	}
+
+	iter := query.Run(j)
+
+	v, ok := iter.Next()
+	if !ok {
+		return nil, errors.New("jq: empty result")
+	}
+
+	if err, ok := v.(error); ok {
+		return nil, errors.Wrap(err, "jq: query failed")
+	}
+
+	if _, ok := iter.Next(); ok {
+		return nil, errors.New("jq: too many results")
+	}
+
+	return v, nil
+}