teddit/inc/processSubredditSidebar.js

module.exports = function() {
  this.processSubredditSidebar = (subreddit, redis, fetch, RedditAPI) => {
    return new Promise(resolve => {
      (async () => {
        let key = `${subreddit}:sidebar`
        redis.get(key, (error, json) => {
          if(error) {
            console.error(`Error getting the ${subreddit}:sidebar key from redis.`, error)
            resolve(null)
          }
          if(json) {
            json = JSON.parse(json)
            let obj = {
              title: json.data.title,
              public_description_html: json.data.public_description_html,
              active_user_count: json.data.active_user_count,
              subscribers: json.data.subscribers,
              created_utc: json.data.created_utc,
              over18: json.data.over18,
              description_html: json.data.description_html
            }
            resolve(obj)
          } else {
            fetch(`https://oauth.reddit.com/r/${subreddit}/about`, redditApiGETHeaders())
            .then(result => {
              if(result.status === 200) {
                result.json()
                .then(json => {
                  redis.setex(key, setexs.sidebar, JSON.stringify(json), (error) => {
                    if(error) {
                      console.error('Error setting the sidebar key to redis.', error)
                      return res.render('index', { json: null, user_preferences: req.cookies })
                    } else {
                      console.log('Fetched the sidebar from reddit API.');
                      (async () => {
                        let obj = {
                          title: json.data.title,
                          public_description_html: json.data.public_description_html,
                          active_user_count: json.data.active_user_count,
                          subscribers: json.data.subscribers,
                          created_utc: json.data.created_utc,
                          over18: json.data.over18,
                          description_html: json.data.description_html
                        }
                        resolve(obj)
                      })()
                    }
                  })
                })
              } else {
              console.error(`Something went wrong while fetching data from reddit API. ${result.status} – ${result.statusText}`)
              console.error(reddit_api_error_text)
              resolve(null)
              }
            }).catch(error => {
              console.error('Error fetching the sidebar.', error)
              resolve(null)
            })
          }
        })
      })()
    })
  }
}