refactor retrieving ICS file

lib/services/crawler.js

@@ -0,0 +1,24 @@
+const request = require('request')
+
+const crawl = async (url) => {
+  return new Promise((resolve, reject) => {
+    console.info(`Started request for URL: ${url}`)
+    request({
+      url,
+      headers: {
+        'Accept-Language': 'en-US, en',
+        'User-Agent': 'request',
+      },
+    }, (err, res, body) => {
+      if (err) {
+        reject(err)
+        return
+      }
+
+      console.info(`Finished request for URL: ${url}`)
+      resolve(body)
+    })
+  })
+}
+
+module.exports = crawl

lib/services/ics-generator.js

@@ -0,0 +1,16 @@
+const ics = require('ics')
+
+const generateICS = async(data) => {
+  return new Promise((resolve, reject) => {
+    ics.createEvent(data, (err, value) => {
+      if (err) {
+        reject(err)
+        return
+      }
+
+      resolve(value)
+    })
+  })
+}
+
+module.exports = generateICS

lib/services/ics-retriever.js

@@ -0,0 +1,18 @@
+const crawl = require('./crawler')
+const parseHTML = require('./parser')
+const generateICS = require('./ics-generator')
+const { getNormalizedUrl } = require('../utils')
+
+const retrieveICS = async (URLparameter) => {
+  try {
+    const url = getNormalizedUrl(URLparameter)
+    const html = await crawl(url)
+    const eventData = parseHTML(html)
+    const icsFile = await generateICS(eventData)
+    return icsFile
+  } catch (err) {
+    throw err
+  }
+}
+
+module.exports = retrieveICS

lib/services/parser.js

@@ -0,0 +1,96 @@
+const dayjs = require('dayjs')
+const cheerio = require('cheerio')
+const { createParserError } = require('../utils')
+
+// NOTE: Specific formatting for `ics` library
+const parseDates = (startDate, endDate) => {
+  const start = startDate ? [
+    startDate.year(),
+    startDate.month() + 1,
+    startDate.date(),
+    startDate.hour(),
+    startDate.minute(),
+  ] : (() => {
+    const now = dayjs()
+
+    return [
+      now.year(),
+      now.month() + 1,
+      now.date()
+    ]
+  })()
+  const diffInMinutes = endDate ?
+    endDate.diff(startDate, 'minutes') :
+    120
+
+  const duration = { minutes: diffInMinutes }
+
+  return {
+    start,
+    duration,
+  }
+}
+
+const parseEventData = (eventData) => {
+  const startDate = eventData.startDate && dayjs(eventData.startDate)
+  const endDate = eventData.endDate && dayjs(eventData.endDate)
+  const { start, duration } = parseDates(startDate, endDate)
+  const { location } = eventData || {}
+  const { address } = location || {}
+
+  const locationStr = location ? [
+    location.name || '',
+    address.streetAddress || '',
+    address.addressLocality || '',
+    address.postalCode || '',
+    address.addressCountry || '',
+  ].join(' ') : ''
+  const cleanedLocationStr = locationStr.replace(/\r?\n|\r/g, ' ')
+  const title = eventData.name || ''
+  const url = eventData.url || ''
+  const description = eventData.description || ''
+
+  return {
+    start,
+    duration,
+    location: cleanedLocationStr,
+    title,
+    url,
+    description,
+  }
+}
+
+const parseHTML = (html) => {
+  try {
+    // NOTE: Mobile web should have serialized
+    // event info in one of the script tags
+    const $ = cheerio.load(html)
+    const $scripts = $('head script[type="application/ld+json"]')
+    const rawData = $scripts.toArray().reduce((data, node) => {
+      const firstNode = node.children[0]
+
+      if (!firstNode || !firstNode.data) {
+        return data
+      }
+
+      if (firstNode.data.startsWith('//<![CDATA')) {
+        return firstNode.data
+      }
+
+      return data
+    }, null)
+
+    if (!rawData) {
+      throw createParserError()
+    }
+
+    const eventData = JSON.parse(rawData.slice(12, -5))
+    const data = parseEventData(eventData)
+
+    return data
+  } catch (err) {
+    throw err
+  }
+}
+
+module.exports = parseHTML