SteemJs Programming: What Happens on the Steem Blockchain in the

  • 时间：2020-09-08 11:19:41
  • 分类：网络文摘
  • 阅读：90 次

Many questions are interesting but the answers are not obvious or easy to get. For example: Who comments most in the last 24 hours?

I am going to show you a pattern to find out the answers to such questions using SteemJs.

Get Current Lastest Block

We need to get the latest block number on the steem blockchain, and we can work out roughly the last 24 hours block range by subtracting 206024 (3 seconds a block).

1
2
3
4
5
6
7
8
9
10
11

function getBlockchainData() {
    return new Promise((resolve, reject) => {
      steem.api.getDynamicGlobalProperties(function(err, result) {
          if (!err) {
              resolve(result);
          } else {
              reject(err);
          }
      });
    });
}
function getBlockchainData() {
    return new Promise((resolve, reject) => {
      steem.api.getDynamicGlobalProperties(function(err, result) {
          if (!err) {
              resolve(result);
          } else {
              reject(err);
          }
      });
    });
}

The current block number can be obtained by:

1
2

const blockchain = await getBlockchainData();
const maxBlock = blockchain.head_block_number;
const blockchain = await getBlockchainData();
const maxBlock = blockchain.head_block_number;

Getting the Block Content

Each block contains transactions, here you would need to parse the list of transactions and look for the particular ones that you are interested. For example, if we want to compute the total producer rewards by witnesses, we can look for “producer_reward”.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

function getBlock(block) {
    return new Promise((resolve, reject) => {
        steem.api.getOpsInBlock(block, false, function(err, result) {
          if (!err) {
              const txCount = result.filter(x=>x.virtual_op===0).length;
              const producer = result.filter(x=>x.op[0] === "producer_reward");
              const witness = producer[0].op[1].producer;
              const reward = producer[0].op[1].vesting_shares;
              resolve({
                count: txCount,
                witness: witness,
                reward: reward.replace(" VESTS", ""),
                time: producer[0].timestamp.replace("T", " ")
              });
          } else {
              reject(err);
          }        
        });
    });
}
function getBlock(block) {
    return new Promise((resolve, reject) => {
        steem.api.getOpsInBlock(block, false, function(err, result) {
          if (!err) {
              const txCount = result.filter(x=>x.virtual_op===0).length;
              const producer = result.filter(x=>x.op[0] === "producer_reward");
              const witness = producer[0].op[1].producer;
              const reward = producer[0].op[1].vesting_shares;
              resolve({
                count: txCount,
                witness: witness,
                reward: reward.replace(" VESTS", ""),
                time: producer[0].timestamp.replace("T", " ")
              });
          } else {
              reject(err);
          }        
        });
    });
}

Writing to Database or a File

We need to write the data into a database, or for simplicity, we can write to a CSV file for later process.

1
2
3
4
5
6
7
8
9
10
11
12
13
14

(async function() {
    const blockchain = await getBlockchainData();
    const maxBlock = blockchain.head_block_number;
    for (let block = maxBlock - 20*60*24; block <= maxBlock; ++ block) {
        try {
            const data = await getBlock(block);
            const s = '"' + data.time + '",' + block + ',"' + data.witness + '",' + data.count + "," + data.reward + "\n";
            log(s);
            fs.appendFileSync('data.csv', s);
        } catch (e) {
            log(e);
        }
    }  
})();
(async function() {
    const blockchain = await getBlockchainData();
    const maxBlock = blockchain.head_block_number;
    for (let block = maxBlock - 20*60*24; block <= maxBlock; ++ block) {
        try {
            const data = await getBlock(block);
            const s = '"' + data.time + '",' + block + ',"' + data.witness + '",' + data.count + "," + data.reward + "\n";
            log(s);
            fs.appendFileSync('data.csv', s);
        } catch (e) {
            log(e);
        }
    }  
})();

Of course, if you want to further develop into a tool, you would need a database, and a background daemon that automatically syncs with the blockchain.

–EOF (The Ultimate Computing & Technology Blog) —

推荐阅读：
数学题：光华小学中、高年级共有学生600名　 数学题：求大阴影部分的面积　 数学题：如何只用这2个水壶从池塘里取得3升的水　 关于可能性的数学题　 数学题：ABCD乘9等于DCBA，问ABCD各是数字几　 数学题：乘积末尾有几个0　 求解答：加工一批服装，每天加工300套，16天可以完成　 数学题－这个工厂原有男工人多少名　 开心“六一”之太阳岛之旅作文　 橘子洲作文　
评论列表
添加评论