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Copy pathdesk-server.go
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188 lines (150 loc) · 4.3 KB
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// Adapted from David Knezić https://github.com/davidknezic/desk/blob/master/bridge.go
// Licensed under MIT (c) David Knezić (https://github.com/davidknezic/desk/blob/master/LICENSE)
package main
import (
"net/http"
"github.com/tarm/serial"
"log"
"strconv"
"time"
)
const UP_HEIGHT = 90
const DOWN_HEIGHT = 10
type DeskHandler struct {
outgoing chan Message
incoming chan Message
}
type MessageType byte
const (
// checking the availability of the desk
TypeAliveRequest MessageType = 0x01
TypeAliveResponse MessageType = 0x02
// setting the height of the desk
TypeSetHeightRequest MessageType = 0x03
// querying the height of the desk
TypeGetHeightRequest MessageType = 0x04
TypeGetHeightResponse MessageType = 0x05
// stopping the desk
TypeStopRequest MessageType = 0x06
// TODO: to be implemented
TypeGetStatusRequest MessageType = 0x07
TypeGetStatusResponse MessageType = 0x08
// moving the desk
TypeMoveUpRequest MessageType = 0x0A
TypeMoveDownRequest MessageType = 0x0B
// the desk notifying about a height change
TypeUpdateHeightEvent MessageType = 0x0C
)
type Message struct {
Type MessageType
Value byte
}
func receiver(c chan<- Message, p *serial.Port) {
message := make([]byte, 3)
buf := make([]byte, 1)
for {
// shift bytes to left
message[0] = message[1]
message[1] = message[2]
// read new byte
_, err := p.Read(buf)
if err != nil {
log.Fatal(err)
}
// append new byte
message[2] = buf[0]
// checksum
if message[0]+message[1] != message[2] {
continue
}
c <- Message{Type: MessageType(message[0]), Value: message[1]}
}
}
func sender(c <-chan Message, p *serial.Port) {
message := make([]byte, 3)
for {
// get a message
m := <-c
log.Println("Message to send", m)
// fill the message buffer
message[0] = byte(m.Type)
message[1] = m.Value
// calculate the checksum
message[2] = message[0] + message[1]
log.Println("Buffer to send", message)
// write the buffer
_, err := p.Write(message)
if err != nil {
log.Fatal(err)
}
}
}
func heightToPercentage(height int) int {
return (height - 68) / 50
}
func heightPercentageToCentimeters(percentage int) int {
factor := float64(percentage) / 100.0
return int(68.0 + 50.0*factor)
}
func main() {
log.Println("Opening serial console...")
c := &serial.Config{
Name: "/dev/ttyS0",
Baud: 9600,
}
s, err := serial.OpenPort(c)
if err != nil {
log.Println("Failed opening serial console.")
log.Fatal(err)
}
var outgoing chan Message = make(chan Message)
var incoming chan Message = make(chan Message)
go sender(outgoing, s)
go receiver(incoming, s)
log.Println("Starting desk-server...")
// http.HandleFunc("/", DeskControlServer)
myFilesHandler := &DeskHandler{outgoing: outgoing, incoming: incoming}
http.HandleFunc("/", myFilesHandler.handler)
http.ListenAndServe(":9987", nil)
}
func (dh *DeskHandler) handler(w http.ResponseWriter, r *http.Request) {
if r.URL.Path[1:] == "down"{
log.Println("Received DOWN request")
setPosition(DOWN_HEIGHT, dh.incoming, dh.outgoing)
} else if r.URL.Path[1:] == "up"{
log.Println("Received UP request")
setPosition(UP_HEIGHT, dh.incoming, dh.outgoing)
} else if r.URL.Path[1:] == "toggle"{
log.Println("Received toggle request")
go togglePosition(dh.incoming, dh.outgoing)
} else{
log.Println("Received specific set height request")
x, err := strconv.Atoi(r.URL.Path[1:])
if err == nil && x > 0{
log.Println(w, "Setting height to %s", x)
setPosition(x, dh.incoming, dh.outgoing)
} else{
log.Println(w, "Error parsing height")
}
}
}
func togglePosition(incoming chan Message, outgoing chan Message){
time.Sleep(2000 * time.Millisecond)
outgoing <- Message{Type: TypeGetHeightRequest}
hi := <-incoming
log.Println("Height is", hi.Value)
int_hi := int(hi.Value)
if int_hi >= 100 {
log.Println("Toggle DOWN")
setPosition(DOWN_HEIGHT, incoming, outgoing)
} else if int_hi < 100 && int_hi >= 1 {
log.Println("Toggle UP")
setPosition(UP_HEIGHT, incoming, outgoing)
}
}
func setPosition(position int, incoming chan Message, outgoing chan Message){
log.Println("Setting desk to", position, "percent height")
height := heightPercentageToCentimeters(position)
log.Println("This corresponds to", height, "cm height")
outgoing <- Message{Type: MessageType(TypeSetHeightRequest), Value: byte(height)}
}