使用异步 node.js 进行 Twitter API 光标导航

Question

我正在尝试使用 async/await 将 Twitter 的 API 与 node.js 一起使用（我承认我是新手），但我正在努力获得下一个光标值。

为什么我下面的getFollowers 函数总是在await 块之前返回？

require('dotenv').config();

const Twitter = require('twitter');
 
const client = new Twitter({
  consumer_key: process.env.API_KEY,
  consumer_secret: process.env.API_KEY_SECRET,
  access_token_key: process.env.ACCESS_TOKEN,
  access_token_secret: process.env.ACCESS_TOKEN_SECRET
});
 
const getFollowers = async (screen_name, count, cursor) => {
    console.log("Cursor: " + cursor);
    const params = {
        screen_name: screen_name,
        count: count,
        cursor: cursor
    };

    const promise = await client.get('followers/list', params)
        .then(data => {
            console.log("This promise is never executed...");
            return data.next_cursor;
        })
        .catch(err => console.error(err));

    return promise;
}

const main = async () => {
    let cursor = -1;
    while (cursor != 0) {
        getFollowers(process.env.SCREEN_NAME, 200, cursor)
            .then(next_cursor => {
                cursor = next_cursor;
                console.log("This promise is never executed either... " + cursor);
            });
    }
}

main();

Answer 1

使用 main() 中的 .then 语句，您无需等待 client.get() 解析，而是等待 data.next_cursor()。因此，client.get() 的承诺仍然悬而未决。

相反，在 getFollowers() 中返回 client.get() 的承诺。这将确保当您在 main() 中调用 getFollowers().then() 时，您指的是 client.get。

编辑：

按照question 中答案的思路，我修改了getFollowers()。它现在包含一个承诺，当光标达到 0 值时，该承诺将被解决。每隔一个值，就会发出一个请求。

我担心请求的速率限制，即设置为每 15 分钟 15 个。由于每个非 0 next_cursor 值都会发出一个新请求，因此对于有很多关注者的帐户，您很快就会达到此限制。

另请注意，检索到的数据将存储在一个数组中。我不确定您的用例到底是什么。

const Twitter = require('twitter');

const client = new Twitter({
    consumer_key: '',
    consumer_secret: '',
    bearer_token: ''
});

let output = [];

const getFollowers = (screen_name, count) => {
    let cursor = -1;

    const params = {
        screen_name: screen_name,
        count: count,
        cursor: cursor
    };

    return new Promise((resolve, reject) => {
        client.get('followers/list', params, function getData(err, data, response) {
            if (err) reject(response.body);
            output.push(data);
            cursor = data.next_cursor;
            
            if (cursor > 0) {
                client.get('followers/list', params, getData);
            }
            if (cursor = 0) {
                resolve('done');
            }
        });    
    });
};

const main = async () => {
   await getFollowers('MozDevNet', 200);
   console.log(output);

};

Answer 2

我放弃了使用Twitter 包的实现，转而使用axios。

require('dotenv').config();

const axios = require('axios');

const credentials = {
    consumer_key: process.env.API_KEY,
    consumer_secret: process.env.API_KEY_SECRET,
    access_token_key: process.env.ACCESS_TOKEN,
    access_token_secret: process.env.ACCESS_TOKEN_SECRET
};

const FOLLOWERS_LIST_ENDPOINT = "https://api.twitter.com/1.1/followers/list.json";

//documentation: https://developer.twitter.com/en/docs/authentication/oauth-2-0/application-only
const generateToken = async () => {
    return process.env.BEARER_TOKEN;
}

//documentation: https://developer.twitter.com/en/docs/twitter-api/v1/accounts-and-users/follow-search-get-users/api-reference/get-followers-list
const getFollowers = async (screen_name, count, cursor) => {
    let token = await generateToken();
    let requestConfig = {
        params: {
            screen_name: screen_name,
            count: count,
            cursor: cursor,
            include_user_entities: false
        },
        headers: { 
            Authorization: `Bearer ${token}` 
        }
    };
    let response = await axios.get(FOLLOWERS_LIST_ENDPOINT, requestConfig);
    let users = response.data.users;
    processUsers(users);
    return response.data.next_cursor;
};

const processUsers = (users) => {
    users.map(user => {
        console.log(user.screen_name);
    });
}
const main = async () => {
    let cursor = -1;
    while (cursor != 0) {
        cursor = await getFollowers(process.env.SCREEN_NAME, 200, cursor);
    }
}

main();