schnutibox/pkg/rfid/rfid.go

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2021-03-30 19:59:26 +02:00
package rfid
import (
"fmt"
"os"
"github.com/rs/zerolog/log"
"go.xsfx.dev/schnutibox/internal/config"
)
const newLine = 40
var charMap = map[byte]string{ //nolint:gochecknoglobals
4: "a",
5: "b",
6: "c",
7: "d",
8: "e",
9: "f",
10: "g",
11: "h",
12: "i",
13: "j",
14: "k",
15: "l",
16: "m",
17: "n",
18: "o",
19: "p",
20: "q",
21: "r",
22: "s",
23: "t",
24: "u",
25: "v",
26: "w",
27: "x",
28: "y",
29: "z",
30: "1",
31: "2",
32: "3",
33: "4",
34: "5",
35: "6",
36: "7",
37: "8",
38: "9",
39: "0",
}
type RFID struct {
Config config.Config
IDChan chan string
}
func NewRFID(config config.Config, id chan string) RFID {
return RFID{config, id}
}
func (r *RFID) Run() error {
d, err := os.Open(r.Config.Reader.Dev)
if err != nil {
return fmt.Errorf("could not open device: %w", err)
}
go func() {
buf := make([]byte, 3)
rfid := ""
for {
// Reading the RFID reader.
_, err := d.Read(buf)
if err != nil {
log.Error().Msg(err.Error())
continue
}
// 40 means "\n" and is an indicator that the input is complete.
// Send the id string to the consumer channel.
if buf[2] == newLine {
r.IDChan <- rfid
rfid = ""
continue
}
// Check if byte is in the charMap and if its true, append it to the rfid string.
// It waits till next read and checks for the newline byte.
c, ok := charMap[buf[2]]
if ok {
rfid += c
}
}
}()
return nil
}