107 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			107 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// +build none
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// Contains a simple whisper peer setup and self messaging to allow playing
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// around with the protocol and API without a fancy client implementation.
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package main
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import (
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	"fmt"
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	"log"
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	"os"
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	"time"
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	"github.com/ethereum/go-ethereum/common"
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	"github.com/ethereum/go-ethereum/crypto"
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	"github.com/ethereum/go-ethereum/logger"
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	"github.com/ethereum/go-ethereum/p2p"
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	"github.com/ethereum/go-ethereum/p2p/nat"
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	"github.com/ethereum/go-ethereum/whisper"
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)
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func main() {
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	logger.AddLogSystem(logger.NewStdLogSystem(os.Stdout, log.LstdFlags, logger.InfoLevel))
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	// Generate the peer identity
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	key, err := crypto.GenerateKey()
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	if err != nil {
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		fmt.Printf("Failed to generate peer key: %v.\n", err)
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		os.Exit(-1)
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	}
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	name := common.MakeName("whisper-go", "1.0")
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	shh := whisper.New()
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	// Create an Ethereum peer to communicate through
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	server := p2p.Server{
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		PrivateKey: key,
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		MaxPeers:   10,
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		Name:       name,
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		Protocols:  []p2p.Protocol{shh.Protocol()},
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		ListenAddr: ":30300",
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		NAT:        nat.Any(),
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	}
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	fmt.Println("Starting Ethereum peer...")
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	if err := server.Start(); err != nil {
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		fmt.Printf("Failed to start Ethereum peer: %v.\n", err)
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		os.Exit(1)
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	}
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	// Send a message to self to check that something works
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	payload := fmt.Sprintf("Hello world, this is %v. In case you're wondering, the time is %v", name, time.Now())
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	if err := selfSend(shh, []byte(payload)); err != nil {
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		fmt.Printf("Failed to self message: %v.\n", err)
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		os.Exit(-1)
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	}
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}
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// SendSelf wraps a payload into a Whisper envelope and forwards it to itself.
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func selfSend(shh *whisper.Whisper, payload []byte) error {
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	ok := make(chan struct{})
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	// Start watching for self messages, output any arrivals
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	id := shh.NewIdentity()
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	shh.Watch(whisper.Filter{
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		To: &id.PublicKey,
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		Fn: func(msg *whisper.Message) {
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			fmt.Printf("Message received: %s, signed with 0x%x.\n", string(msg.Payload), msg.Signature)
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			close(ok)
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		},
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	})
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	// Wrap the payload and encrypt it
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	msg := whisper.NewMessage(payload)
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	envelope, err := msg.Wrap(whisper.DefaultPoW, whisper.Options{
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		From: id,
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		To:   &id.PublicKey,
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		TTL:  whisper.DefaultTTL,
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	})
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	if err != nil {
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		return fmt.Errorf("failed to seal message: %v", err)
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	}
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	// Dump the message into the system and wait for it to pop back out
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	if err := shh.Send(envelope); err != nil {
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		return fmt.Errorf("failed to send self-message: %v", err)
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	}
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	select {
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	case <-ok:
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	case <-time.After(time.Second):
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		return fmt.Errorf("failed to receive message in time")
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	}
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	return nil
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}
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