Question

10.8. 

10.8.1. 

			
const Web3 = require('web3');

const web3 = new Web3(new Web3.providers.WebsocketProvider('wss://mainnet.infura.io/ws'));

var subscription = web3.eth.subscribe('pendingTransactions', function(error, result){
    if (!error)
        console.log(result);
})
.on("data", function(transaction){
    console.log(transaction);
});

// unsubscribes the subscription
subscription.unsubscribe(function(error, success){
    if(success)
        console.log('Successfully unsubscribed!');
});
			
			

			
const Web3 = require('web3');

const web3wss = new Web3(new Web3.providers.WebsocketProvider('wss://mainnet.infura.io/ws'));
const web3 = new Web3("https://mainnet.infura.io/CsS9shwaAab0z7B4LP2d");



var subscription = web3wss.eth.subscribe('pendingTransactions', function(error, result){
    if (!error){
        console.log("--------------------" + result +"--------------------");
        var receipt = web3.eth.getTransactionReceipt(result).then(console.log);
     }
})
.on("data", function(transaction){
    console.log(transaction);
});

// unsubscribes the subscription
subscription.unsubscribe(function(error, success){
    if(success)
        console.log('Successfully unsubscribed!');
});
			
	
			
			

10.8.2. 订阅 newBlockHeaders

			
#!/usr/bin/env node
const Web3 = require('web3');

const web3 = new Web3(new Web3.providers.WebsocketProvider('wss://mainnet.infura.io/ws'));

const subscription = web3.eth.subscribe('newBlockHeaders', (error, blockHeader) => {
  if (error) return console.error(error);

  console.log('Successfully subscribed!', blockHeader);
}).on('data', (blockHeader) => {
  console.log('data: ', blockHeader);
});

// unsubscribes the subscription
subscription.unsubscribe((error, success) => {
  if (error) return console.error(error);

  console.log('Successfully unsubscribed!');
});			
			
			

10.8.3. 订阅 log

			
#!/usr/bin/env node
const Web3 = require('web3');

const web3 = new Web3(new Web3.providers.WebsocketProvider('wss://mainnet.infura.io/ws'));

var subscription = web3.eth.subscribe('logs', {
	fromBlock: 5709426,
    address: '0x7fFdCccC3E7e33C6163393195A947A6d45f25814'
}, function(error, result){
    if (!error)
        console.log(result);
})
.on("data", function(log){
    console.log(log);
})
.on("changed", function(log){
});

// unsubscribes the subscription
subscription.unsubscribe(function(error, success){
    if(success)
        console.log('Successfully unsubscribed!');
});
			
			

10.8.4. 订阅同步状态

			
const Web3 = require('web3');

const web3 = new Web3(new Web3.providers.WebsocketProvider('wss://mainnet.infura.io/ws'));

var subscription = web3.eth.subscribe('syncing', function(error, sync){
    if (!error)
        console.log(sync);
})
.on("data", function(sync){
    // show some syncing stats
})
.on("changed", function(isSyncing){
    if(isSyncing) {
        // stop app operation
    } else {
        // regain app operation
    }
});

// unsubscribes the subscription
subscription.unsubscribe(function(error, success){
    if(success)
        console.log('Successfully unsubscribed!');
});