go-libp2p-webrtc-direct/examples/libp2p-echo/main.go

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2019-02-25 19:10:59 +00:00
package main
import (
"bufio"
"context"
"crypto/rand"
"flag"
"fmt"
"io"
"io/ioutil"
"log"
mrand "math/rand"
golog "github.com/ipfs/go-log"
libp2p "github.com/libp2p/go-libp2p"
crypto "github.com/libp2p/go-libp2p-crypto"
host "github.com/libp2p/go-libp2p-host"
net "github.com/libp2p/go-libp2p-net"
peer "github.com/libp2p/go-libp2p-peer"
pstore "github.com/libp2p/go-libp2p-peerstore"
ma "github.com/multiformats/go-multiaddr"
gologging "github.com/whyrusleeping/go-logging"
direct "github.com/libp2p/go-libp2p-webrtc-direct"
"github.com/pions/webrtc"
mplex "github.com/whyrusleeping/go-smux-multiplex"
)
// makeBasicHost creates a LibP2P host with a random peer ID listening on the
// given multiaddress. It won't encrypt the connection if insecure is true.
func makeBasicHost(listenPort int, insecure bool, randseed int64) (host.Host, error) {
// If the seed is zero, use real cryptographic randomness. Otherwise, use a
// deterministic randomness source to make generated keys stay the same
// across multiple runs
var r io.Reader
if randseed == 0 {
r = rand.Reader
} else {
r = mrand.New(mrand.NewSource(randseed))
}
// Generate a key pair for this host. We will use it at least
// to obtain a valid host ID.
priv, _, err := crypto.GenerateKeyPairWithReader(crypto.RSA, 2048, r)
if err != nil {
return nil, err
}
transport := direct.NewTransport(
webrtc.Configuration{},
new(mplex.Transport),
)
opts := []libp2p.Option{
libp2p.ListenAddrStrings(fmt.Sprintf("/ip4/127.0.0.1/tcp/%d/http/p2p-webrtc-direct", listenPort)),
libp2p.Identity(priv),
libp2p.DisableRelay(),
libp2p.Transport(transport),
}
if insecure {
opts = append(opts, libp2p.NoSecurity)
}
basicHost, err := libp2p.New(context.Background(), opts...)
if err != nil {
return nil, err
}
// Build host multiaddress
hostAddr, _ := ma.NewMultiaddr(fmt.Sprintf("/ipfs/%s", basicHost.ID().Pretty()))
// Now we can build a full multiaddress to reach this host
// by encapsulating both addresses:
addr := basicHost.Addrs()[0]
fullAddr := addr.Encapsulate(hostAddr)
log.Printf("I am %s\n", fullAddr)
if insecure {
log.Printf("Now run \"./libp2p-echo -l %d -d %s -insecure\" on a different terminal\n", listenPort+1, fullAddr)
} else {
log.Printf("Now run \"./libp2p-echo -l %d -d %s\" on a different terminal\n", listenPort+1, fullAddr)
}
return basicHost, nil
}
func main() {
// LibP2P code uses golog to log messages. They log with different
// string IDs (i.e. "swarm"). We can control the verbosity level for
// all loggers with:
golog.SetAllLoggers(gologging.INFO) // Change to DEBUG for extra info
// Parse options from the command line
listenF := flag.Int("l", 0, "wait for incoming connections")
target := flag.String("d", "", "target peer to dial")
insecure := flag.Bool("insecure", false, "use an unencrypted connection")
seed := flag.Int64("seed", 0, "set random seed for id generation")
flag.Parse()
if *listenF == 0 {
log.Fatal("Please provide a port to bind on with -l")
}
// Make a host that listens on the given multiaddress
ha, err := makeBasicHost(*listenF, *insecure, *seed)
if err != nil {
log.Fatal(err)
}
// Set a stream handler on host A. /echo/1.0.0 is
// a user-defined protocol name.
ha.SetStreamHandler("/echo/1.0.0", func(s net.Stream) {
log.Println("Got a new stream!")
if err := doEcho(s); err != nil {
log.Println(err)
s.Reset()
} else {
s.Close()
}
})
if *target == "" {
log.Println("listening for connections")
select {} // hang forever
}
/**** This is where the listener code ends ****/
// The following code extracts target's the peer ID from the
// given multiaddress
ipfsaddr, err := ma.NewMultiaddr(*target)
if err != nil {
log.Fatalln(err)
}
pid, err := ipfsaddr.ValueForProtocol(ma.P_IPFS)
if err != nil {
log.Fatalln(err)
}
peerid, err := peer.IDB58Decode(pid)
if err != nil {
log.Fatalln(err)
}
// Decapsulate the /ipfs/<peerID> part from the target
// /ip4/<a.b.c.d>/ipfs/<peer> becomes /ip4/<a.b.c.d>
targetPeerAddr, _ := ma.NewMultiaddr(
fmt.Sprintf("/ipfs/%s", peer.IDB58Encode(peerid)))
targetAddr := ipfsaddr.Decapsulate(targetPeerAddr)
// We have a peer ID and a targetAddr so we add it to the peerstore
// so LibP2P knows how to contact it
ha.Peerstore().AddAddr(peerid, targetAddr, pstore.PermanentAddrTTL)
log.Println("opening stream")
// make a new stream from host B to host A
// it should be handled on host A by the handler we set above because
// we use the same /echo/1.0.0 protocol
s, err := ha.NewStream(context.Background(), peerid, "/echo/1.0.0")
if err != nil {
log.Fatalln(err)
}
_, err = s.Write([]byte("Hello, world!\n"))
if err != nil {
log.Fatalln(err)
}
out, err := ioutil.ReadAll(s)
if err != nil {
log.Fatalln(err)
}
log.Printf("read reply: %q\n", out)
}
// doEcho reads a line of data a stream and writes it back
func doEcho(s net.Stream) error {
buf := bufio.NewReader(s)
str, err := buf.ReadString('\n')
if err != nil {
return err
}
log.Printf("read: %s\n", str)
_, err = s.Write([]byte(str))
return err
}