scrapper-api/app.js

const config = require('config');
const axios = require("axios");
const cheerio = require("cheerio");
const express = require('express');
const cors = require('cors');
const MongoClient = require('mongodb').MongoClient;
const ObjectID = require('mongodb').ObjectID;

var apartments = require('./apartments.js');
var houses = require('./houses.js');

// jobs
var mongoUrl = config.get("mongo");
var agendaDb = config.get("agenda");
const Agenda = require('agenda').Agenda;
const agenda = new Agenda({ db: { address: agendaDb } });
agenda.define('scrape', async function (job, done) {
  const { _id } = job.attrs.data;
  try {
    const dbo = client.db(database);
    let collection = dbo.collection('scrapes');
    let scrape = await collection.findOne({ _id: _id });

    for (var page = 1; page <= scrape.pageCount; page++) {
      console.log("scrapping page " + page)

      const filterPage = await axios(scrape.sourceUrl + `/${page}`);
      const html = filterPage.data;
      const $ = cheerio.load(html);

      const propertyLinks = $('#placardContainer .property-link').map(function () {
        return $(this).attr('href');
      }).get();

      var properties = [];
      for (const link of propertyLinks) {
        try {
          var response = await axios(link);

          var property = apartments.apartment(cheerio.load(response.data));
          properties.push(property);
          console.log(`${link} scraped.`);
        }catch(err){
          console.error(`${link} scrape failed.`);
        }
      }
    }

    await collection.updateOne({ _id: _id }, { $set: { status: "done", result: properties } });
    console.log(`${_id} scraped.`);
    return done();
  } catch (err) {
    console.log(err);
  }
});
(async function () {
  await agenda.start();
})();

// express application
const app = express();

app.use(express.json());
app.use(cors());

// database setup
var mongoUrl = config.get("mongo");
var database = config.get("database");

var client = undefined;
MongoClient.connect(mongoUrl, function (err, db) {
  if (err) throw err;
  console.log("Database created!");
  console.log(mongoUrl);
  client = db;

  var dbo = db.db(database);
  dbo.createCollection("scrapes", function (err, res) {
    if (err) {
      console.log("Collection already created!");
      return;
    }
    console.log("Collection created!");
  });
});

app.get("/scrapes", async (req, res) => {
  try {
    const dbo = client.db(database);
    let collection = dbo.collection('scrapes');
    let data = await collection.find({}).toArray();
    return res.json(data);
  } catch (err) {
    console.log(err);
    return res.status(500).json();
  }
});
app.get("/scrapes/:id", async (req, res) => {
  const id = req.params.id;
  try {
    const dbo = client.db(database);
    let collection = dbo.collection('scrapes');

    var o_id = new ObjectID(id);
    let data = await collection.findOne({ _id: o_id });
    return res.json(data);
  } catch (err) {
    console.log(err);
    res.status(500).json();
  }
});
app.post("/scrapes/", async (req, res) => {
  const location = req.body.location;
  const price = req.body.price;
  const beds = req.body.beds;
  const type = req.body.type;
  const lifestyle = req.body.lifestyle;

  // query builder
  var query = `https://www.apartments.com`;
  if (type) {
    query += `/${type}`;
  }
  if (location) {
    var locationQuery = location.replace(", ", "-").replace(" ", "-").toLowerCase();
    query += `/${locationQuery}`;
  }
  if (beds) {
    query += `/${beds}-bedrooms`;
  }

  if (price) {
    if (beds) {
      query += `-over-${price}`;
    } else {
      query += `/over-${price}`;
    }
  }
  if (lifestyle) {
    query += `/${lifestyle}`;
  }

  console.log(query);

  const filterPage = await axios(query);
  const html = filterPage.data;
  const $ = cheerio.load(html);
  var $pageRange = $(".pageRange");
  var pagesCount = 0;
  var resultCount = 0;
  if (!$pageRange.length) {
    let propertyLinks = $('#placardContainer .property-link').map(function () {
      return $(this).attr('href');
    }).get();
    if (!propertyLinks.length) {
      console.error("No results");
      return res.status(404).json();
    }
    resultCount = propertyLinks.length;
  } else {
    pagesCount = $pageRange.text().slice($pageRange.text().lastIndexOf("of ") + 3);
    resultCount = pagesCount * 25;
  }

  try {
    const dbo = client.db(database);
    let collection = dbo.collection('scrapes');
    const dt = new Date();
    dt.setSeconds( dt.getSeconds() + resultCount );
    let res = await collection.insertOne({
      count: resultCount,
      pageCount: pagesCount,
      estimate: dt,
      sourceUrl: query,
      location: location,
      filters: [
        { name: 'price', value: price },
        { name: 'beds', value: beds },
        { name: 'type', value: type },
        { name: 'lifestyle', value: lifestyle },
      ],
      status: "requested"
    });
    console.log(res);
  } catch (err) {
    console.log(err);
    return res.status(500).json();
  }
  return res.json();
});
app.patch("/scrapes/:id/execute", async (req, res) => {
  const id = req.params.id;

  try {
    const dbo = client.db(database);
    let collection = dbo.collection('scrapes');

    var o_id = new ObjectID(id);
    var newvalues = { $set: { status: "pending" } };
    await collection.updateOne({ _id: o_id }, newvalues);
    agenda.now('scrape', { _id: o_id });
    return res.status(204).json();
  } catch (err) {
    console.log(err);
    res.status(500).json();
  }
});

const port = 3333;
app.listen(port, () => {
  console.log(`Example app listening at http://localhost:${port}`)
});

// Handles graceful stopping of jobs
function graceful() {
  agenda.stop(function () {
    client.close(function (e) {
      if (e) logger.error(e);
      process.exit(0);
    });
  });
}

process.on('SIGTERM', graceful);
process.on('SIGINT', graceful);