Web scraping with Julia and PhantomJS

By: Alvaro "Blag" Tejada Galindo

Re-posted from: http://blagrants.blogspot.com/2014/07/web-scrapping-with-julia-and-phatomjs.html

As I have been reading some PhantomJS books and I’m always looking to develop something nice using Julia…I thought that integrate them would be an awesome idea -;)

I thought about Twitter and the hashtags…wouldn’t it be nice to write a PhantomJS script to webscrape Twitter and get all the hashtags that I have used?

For this particular script…I’m taking the hashtags from the first 5 Twitter pages linked to my profile…

Hashtags.js 
var system = require('system');

var webpage = require('webpage').create();
webpage.viewportSize = { width: 1280, height: 800 };
webpage.scrollPosition = { top: 0, left: 0 };

var userid = system.args[1];
var profileUrl = "http://www.twitter.com/" + userid;

webpage.open(profileUrl, function(status) {
 if (status === 'fail') {
  console.error('webpage did not open successfully');
  phantom.exit(1);
 }
 var i = 0,
 top,
 queryFn = function() {
  return document.body.scrollHeight;
 };
 setInterval(function() {
  top = webpage.evaluate(queryFn);
  i++;
   
  webpage.scrollPosition = { top: top + 1, left: 0 };

  if (i >= 5) {
   var twitter = webpage.evaluate(function () {
    var twitter = [];
    forEach = Array.prototype.forEach;
    var tweets = document.querySelectorAll('[data-query-source="hashtag_click"]');
    forEach.call(tweets, function(el) {
     twitter.push(el.innerText);
    });
    return twitter;
   });

   twitter.forEach(function(t) {
    console.log(t);
   });

   phantom.exit();
  }
}, 3000);
});

If we run this…we’re going to have this output…

Now…what I want to do with this information…is to send it to Julia…and get the most used hashtags…so I will summarize them and then get rid of the ones that only appear once…
Let’s see the Julia code…
Twitter_Hashtags.jl 
tweets = readall(`phantomjs Hashtags.js Blag`)
tweets = split(tweets,"\n")
hashtags = Dict()
for hash in tweets
 try
  hashtags[hash] += 1
 catch e
  hashtags[hash] = 1
 end
end

filter!((k,v)->v>1,hashtags)

for (k,v) in hashtags
 println("$k has been mentioned $v times")
end

When we run this code…we’re going to have this output…

I still don’t know how to sort Dicts in Julia…so bear with me -:)

Anyway…by looking at the output…we can have my top 3 hashtags -;)

#LeapMotion ==> 14 times
#Flare3D ==> 11 times
#DevHangout ==> 8 times

Hope you like this and see you next time -:)

Greetings,

Blag.
Development Culture.