递归使用 async/await 节点请求包

Question

我正在使用 response 节点库发出一个 http 请求，我正在尝试递归调用它（如果用户在某一天进行了提交，请检查前一天。如果没有，请计数获得连胜的所有日子）。

问题是那行

const githubResponse = await request(options);

吐出错误

Unexpected token o in JSON at position 1

await request(options) 似乎没有 return 我期待的 JSON GitHub API 响应，而是 githubResponse 似乎成为我无法使用的对象。我猜我使用 async/await 不当，但我不确定如何解决它。

async function checkUserCommitForDate(user, date) {
    const options = {
        url: `https://api.github.com/search/commits?q=author:${user}+author-date:${date}`,
        headers: {
            'User-Agent': 'request',
            'Accept': 'application/vnd.github.cloak-preview'
        }
    };
    const githubResponse = await request(options)

    // I get an error on the next line

    if (JSON.parse(githubResponse).total_count > 0) {
        const previousDaysDate = moment(date).subtract(1, 'day').format('YYYY-MM-DD');
        let streakCounter = await checkUserCommitForDate(user, previousDaysDate);
        streakCounter++;
        console.log('streakCounter', streakCounter);
        return streakCounter;
    } else {
        return 0;
    }
}

更新：这似乎不是一个承诺，所以我需要以不同的方式格式化它（作为回调）。当我尝试这个时：

async function checkUserCommitForDate(user, date) {
    const options = {
        url: `https://api.github.com/search/commits?q=author:${user}+author-date:${date}`,
        headers: {
            'User-Agent': 'request',
            'Accept': 'application/vnd.github.cloak-preview'
        }
    };
    request(options, async function (error, response, body) {
        console.log('error:', error); // Print the error if one occurred
        if (JSON.parse(body).total_count > 0) {
            const previousDaysDate = moment(date).subtract(1, 'day').format('YYYY-MM-DD');
            let streakCounter = await checkUserCommitForDate(user, previousDaysDate);
            streakCounter++;
            console.log('streakCounter', streakCounter);
            return streakCounter;
        } else {
            return 0;
        }
    });
}

行

let streakCounter = await checkUserCommitForDate(user, previousDaysDate);

成为问题，因为 streakCounter 未定义，使日志 NaN.

Answer 1

我使用这里的 promisify example 将其转换为这个并且成功了！

async function checkUserCommitForDate(user, date) {
    const options = {
        url: `https://api.github.com/search/commits?q=author:${user}+author-date:${date}`,
        headers: {
            'User-Agent': 'request',
            'Accept': 'application/vnd.github.cloak-preview'
        }
    };

    const githubResponse = await promisify(request)(options);

    if (JSON.parse(githubResponse.body).total_count > 0) {
        const previousDaysDate = moment(date).subtract(1, 'day').format('YYYY-MM-DD');
        let streakCounter = await checkUserCommitForDate(user, previousDaysDate);
        streakCounter++;
        console.log('streakCounter', streakCounter);
        return streakCounter;
    } else {
        return 0;
    }
}

function promisify(fn) {
    return function (...args) {
        return new Promise((resolve, reject) => {
            fn(...args, (err, result) => {
                if (err) return reject(err);
                resolve(result);
            });
        });
    };
};

Answer 2

如评论中所述request uses callbacks instead of returning a promise and you dont really need to promisify it by yourself since there's already a pacakge for that called request-promise。

在您的代码中使用它应该直接与 async/await

开箱即用

Answer 3

如果升级到 Node 8 LTS，那么原生 util.promisfy 可以如下使用：

const { promisify } = require('util')
const request = promisify(require('request'))

async function checkUserCommitForDate(user, date) {
  const options = {
    url: `https://api.github.com/search/commits?q=author:${user}+author-date:${date}`,
    headers: {
      'User-Agent': 'request',
      'Accept': 'application/vnd.github.cloak-preview',
      'json':true
    }
  };

  try{
    const githubResponse = await request(options);
    if (githubResponse.body.total_count > 0) {
      const previousDaysDate = moment(date).subtract(1, 'day').format('YYYY-MM-DD');
      let streakCounter = await checkUserCommitForDate(user, previousDaysDate);
      streakCounter++;
      console.log('streakCounter', streakCounter);
      return streakCounter;
    } else {
        return 0;
    }
  }
  catch(err){
    console.error(err)
    return 0;
  }
}

在选项中使用 json:true 将减少另一个解析步骤，因为响应将在 JSON格式.

递归使用 async/await 节点请求包

Using async/await recursively with node request package

recursion

asynchronous

node.js

async-await

node-request