Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Blogpost Firebase II - Full code
const ONE_HOUR = 3600000
var functions = require('firebase-functions');
const URL_THE_GUARDIAN = "https://www.theguardian.com/uk/london/rss"
var Client = require('node-rest-client').Client;
var client = new Client();
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);
exports.fetchGuardianWithoutCache = functions.https.onRequest((req, res) => {
console.log("Fetching The Guardian Without Cache");
return request(URL_THE_GUARDIAN)
.then(data => cleanUp(data))
.then(items => saveInDatabase2(items))
.then(items => response(res, items, 201))
});
exports.fetchGuardian = functions.https.onRequest((req, res) => {
console.log("Fetching The Guardian");
var lastEdition = admin.database().ref('/feed/guardian');
return lastEdition
.once('value')
.then(snapshot => {
if (isCacheValid(snapshot)) {
return response(res, snapshot.val(), 200)
} else {
return request(URL_THE_GUARDIAN)
.then(data => cleanUp(data))
.then(items => save(lastEdition, items))
.then(items => response(res, items, 201))
}
})
});
function save(databaseRef, items) {
return databaseRef
.set({
date: new Date(Date.now()).toISOString(),
items: items
})
.then(() => {
return Promise.resolve(items);
})
}
function saveInDatabase2(items) {
return admin.database().ref('/feed/guardian')
.set({ items: items })
.then(() => {
return Promise.resolve(items);
})
}
function request(url) {
return new Promise(function (fulfill, reject) {
client.get(url, function (data, response) {
fulfill(data)
})
})
}
function response(res, items, code) {
return Promise.resolve(res.status(code)
.type('application/json')
.send(items))
}
function isCacheValid(snapshot) {
return (
snapshot.exists() &&
elapsed(snapshot.val().date) < ONE_HOUR
)
}
function handleCache(snapshot, res, lastEdition) {
if (snapshot.exists() && elapsed(snapshot.val().date) < ONE_HOUR) {
console.log("Exist & still valid -> return from DB")
return res.status(200)
.type('application/json')
.send(snapshot.val());
} else {
console.log("Exist but old -> continue")
}
console.log("Missing -> fetch")
client.get(URL_THE_GUARDIAN, function (data, response) {
console.log("feed fetched");
//const items = parseChannel(data.rss.channel)
const items = cleanUp(data)
return lastEdition
.set({
date: new Date(Date.now()).toISOString(),
items: items
})
.then(function () {
res.status(201)
.type('application/json')
.send(items)
})
});
}
function elapsed(date) {
const then = new Date(date)
const now = new Date(Date.now())
return now.getTime() - then.getTime()
}
function cleanUp(data) {
console.log("Cleaning up data: ", data)
// Empty array to add clean up elements
const items = []
// We are only interested in 'channel' children
const channel = data.rss.channel
channel.item.forEach(element => {
item = {
title: element.title,
description: element.description,
date: element.pubDate,
creator: element['dc:creator'],
media: []
}
// Iterates through all the elements named '<media:content>' extracting the info we care about
element['media:content'].forEach(mediaContent => {
item.media.push({
url: mediaContent.$.url, // Parses media:content url attribute
credit: mediaContent['media:credit']._ // Parses media:cretit tag content
})
});
items.push(item);
});
return Promise.resolve(items);
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment