image2slack

image2slack.js

const fs = require('fs');
const twitter = require('twitter');
const redis = require('redis');

class RedisClient {
  constructor() {
    this.client = redis.createClient();
    this.key = "medium";
  }

  deleteDuplicateQueue(obj) {
    const medium = obj.medium;
    const redisMedium = this.client.lrange(this.key, 0, -1);
    obj.medium = medium.filter(elem => !redisMedium.includes(elem));
  }

  destroyAllQueue() {
    for (let index = 0; index < this.client.llen(this.key); index++) {
      this.client.lpop(this.key);
    }
  }

  insertQueue(tweets) {
    tweets.forEach((value, index) => {
      this.client.lpush(this.key, value);
    });
  }
}

const authorize = async () => {
  const readFileAsync = path => {
    return new Promise((resolve, reject) => {
      fs.readFile(path, 'utf8', (err, data) => {
        if (err) { reject(err); return; }
        resolve(data);
      });
    });
  };

  const twitterConfig = JSON.parse(await readFileAsync('twitter_config.json'));
  const twitterClient = new twitter(twitterConfig);
  const slackClient = await JSON.parse(readFileAsync('slack_config.json'));
  
  return {
    'twitterClient': twitterClient,
    'slackClient': slackClient
  };
};

const getFavorites = async client => {
  const fetchFavoriteAsync = () => {
    return new Promise((resolve, reject) => {
      /*
        fetch 50 favorites per 10 minutes. 
        if fetched tweets are duplicated, destroy
      */
      client.get('favorites/list', {
        screen_name: '9z0q',
        count: 50
      }, (error, tweets, response) => {
        if(error) reject(error);
        resolve(tweets);
      });
    });
  }

  const redis = new RedisClient();
  const tweets = await fetchFavoriteAsync();
  const medium = tweets.map(elem => {
    const media = elem.entities.media;
    if(!media) return media;
  }).flat;

  redis.deleteDuplicateQueue({medium});
  redis.destroyAllQueue();
  redis.insertQueue(medium);

  return medium;
};

const postSlack = async params => {
  const response = await fetch(
    'https://slack.com/api/chat.postMessage',
    {
      token: params.token,
      channel: params.channel,
      username: "XXX",
      text: "",
      attachments: [{
        fields: [{
            title: "XXX",
            value: "XXX"
        }],
        image_url: params.image_url
      }]
    }
  );

  return response;
}

const {twitterClient, slackClient} = authorize();

getFavorites(twitterClient).then(tweets => {
  tweets.forEach((value, index) => {
    postSlack({
      token: slackClient.token,
      channel: slackClient.channel,
      username: slackClient.username,
      image_url: "XXX"
    });
  });
});