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package main
import (
"fmt"
"log"
math_rand "math/rand"
"time"
"github.com/schollz/peerdiscovery"
"github.com/schollz/progressbar/v3"
)
func main() {
fmt.Println("Scanning for 30 seconds to find LAN peers")
// show progress bar
go func() {
bar := progressbar.New(300)
for i := 0; i < 300; i++ {
bar.Add(1)
time.Sleep(100 * time.Millisecond)
}
fmt.Print("\n")
}()
// discover peers
discoveries, err := peerdiscovery.Discover(peerdiscovery.Settings{
Limit: -1,
Payload: []byte(randStringBytesMaskImprSrc(10)),
Delay: 100 * time.Millisecond,
TimeLimit: 30 * time.Second,
Notify: func(d peerdiscovery.Discovered) {
log.Println(d)
},
MulticastAddress: "239.255.255.250",
})
// print out results
if err != nil {
log.Fatal(err)
} else {
if len(discoveries) > 0 {
fmt.Printf("Found %d other computers\n", len(discoveries))
for i, d := range discoveries {
fmt.Printf("%d) '%s' with payload '%s'\n", i, d.Address, d.Payload)
}
} else {
fmt.Println("Found no devices. You need to run this on another computer at the same time.")
}
}
}
// src is seeds the random generator for generating random strings
var src = math_rand.NewSource(time.Now().UnixNano())
const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
const (
letterIdxBits = 6 // 6 bits to represent a letter index
letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
)
// RandStringBytesMaskImprSrc prints a random string
func randStringBytesMaskImprSrc(n int) string {
b := make([]byte, n)
// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
if remain == 0 {
cache, remain = src.Int63(), letterIdxMax
}
if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
b[i] = letterBytes[idx]
i--
}
cache >>= letterIdxBits
remain--
}
return string(b)
}
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