Initial commit of source.

webgui/webgui.go

@@ -0,0 +1,180 @@
+/*
+Copyright (c) 2015, Hendrik van Wyk
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+this list of conditions and the following disclaimer in the documentation
+and/or other materials provided with the distribution.
+
+* Neither the name of invertergui nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+package webgui
+
+import (
+	"fmt"
+	"github.com/hpdvanwyk/invertergui/datasource"
+	"html/template"
+	"net/http"
+	"time"
+)
+
+var leds = map[int]string{
+	0: "Temperature",
+	1: "Low battery",
+	2: "Overload",
+	3: "Inverter",
+	4: "Float",
+	5: "Bulk",
+	6: "Absorption",
+	7: "Mains",
+}
+
+type WebGui struct {
+	source   datasource.DataSource
+	reqChan  chan *statusError
+	respChan chan statusError
+	stopChan chan struct{}
+	template *template.Template
+}
+
+func NewWebGui(source datasource.DataSource, pollRate time.Duration) *WebGui {
+	wg := new(WebGui)
+	wg.source = source
+	wg.reqChan = make(chan *statusError)
+	wg.respChan = make(chan statusError)
+	wg.stopChan = make(chan struct{})
+	var err error
+	wg.template, err = template.New("thegui").Parse(htmlTemplate)
+	if err != nil {
+		panic(err)
+	}
+	go wg.dataPoll(pollRate)
+	return wg
+}
+
+//TemplateInput is exported to be used as an argument to the http template package.
+type TemplateInput struct {
+	Error error
+
+	OutCurrent string
+	OutVoltage string
+	OutPower   string
+
+	InCurrent string
+	InVoltage string
+	InPower   string
+
+	InMinOut string
+
+	BatVoltage string
+	BatCurrent string
+	BatPower   string
+
+	InFreq string
+
+	Leds []string
+}
+
+func (w *WebGui) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
+	statusErr := <-w.respChan
+
+	tmpInput := buildTemplateInput(&statusErr)
+
+	err := w.template.Execute(rw, tmpInput)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func buildTemplateInput(statusErr *statusError) *TemplateInput {
+	status := statusErr.status
+	outPower := status.OutVoltage * status.OutCurrent
+	inPower := status.InCurrent * status.InVoltage
+
+	tmpInput := &TemplateInput{
+		Error:      statusErr.err,
+		OutCurrent: fmt.Sprintf("%.3f", status.OutCurrent),
+		OutVoltage: fmt.Sprintf("%.3f", status.OutVoltage),
+		OutPower:   fmt.Sprintf("%.3f", outPower),
+		InCurrent:  fmt.Sprintf("%.3f", status.InCurrent),
+		InVoltage:  fmt.Sprintf("%.3f", status.InVoltage),
+		InFreq:     fmt.Sprintf("%.3f", status.InFreq),
+		InPower:    fmt.Sprintf("%.3f", inPower),
+
+		InMinOut: fmt.Sprintf("%.3f", inPower-outPower),
+
+		BatCurrent: fmt.Sprintf("%.3f", status.BatCurrent),
+		BatVoltage: fmt.Sprintf("%.3f", status.BatVoltage),
+		BatPower:   fmt.Sprintf("%.3f", status.BatVoltage*status.BatCurrent),
+	}
+	for i := 7; i >= 0; i-- {
+		if status.Leds[i] == 1 {
+			tmpInput.Leds = append(tmpInput.Leds, leds[i])
+		}
+	}
+	return tmpInput
+}
+
+func (w *WebGui) Stop() {
+	close(w.stopChan)
+}
+
+type statusError struct {
+	status datasource.MultiplusStatus
+	err    error
+}
+
+// dataPoll will issue a request for a new status every pollRate. It will send its currently stored status
+// to respChan if anything reads from it.
+func (w *WebGui) dataPoll(pollRate time.Duration) {
+	ticker := time.NewTicker(pollRate)
+	var statusErr statusError
+	go w.getStatus()
+	gettingStatus := true
+	for {
+		select {
+		case <-ticker.C:
+			if gettingStatus == false {
+				go w.getStatus()
+				gettingStatus = true
+			}
+		case s := <-w.reqChan:
+			if s.err != nil {
+				statusErr.err = s.err
+			} else {
+				statusErr.status = s.status
+				statusErr.err = nil
+			}
+			gettingStatus = false
+		case w.respChan <- statusErr:
+		case <-w.stopChan:
+			return
+		}
+	}
+}
+
+func (w *WebGui) getStatus() {
+	statusErr := new(statusError)
+	statusErr.err = w.source.GetData(&statusErr.status)
+	w.reqChan <- statusErr
+}