Finding common friends of a given steam users, and creating a graph network.

README.md

Steam Friends

This is a simple ruby script to create (in adjacent list format) graph networks of a given array of steam users. You can also use this script to find the most common friends of a given group of users.

Examples

Below are some examples of using this script.

Creating a graph network

outputCSV(createNetwork(['yigitcan2', 'Boneslark']), 'output.csv');

This line gets the friends of the users yigitcan2 and Boneslark, then outputs a csv file; representing the nodes and edges of the friends network of these users.

Finding the common friends

puts findCommon(['yigitcan2', 'Boneslark']).inspect;

This line finds the common friends of the users yigitcan2 and Boneslark, outputs the resulting request to the $stdin.

steam_friends.rb

require 'uri'
require 'open-uri'
require 'nokogiri'

# Outputs an adjacent list graph network in csv format.
# @param network {Object} key/value mappings of users to their friends. 
# @param file_name {String} file to save the generated csv string.
def outputCSV(network, file_name = 'output.csv')
	output = File.open(file_name, 'w');

	network.each{|name, friends|
		output.write(([name] + friends).join(';') + "\n");
	}	

	output.close
end

# Returns an url that points to the given user's friends page.
# @param name {String} name/id of the user.
# @return {String} full url to the friends page of the user.
def getURLByName(name)
	path = name.match(/[^0-9]+/) ? 'id' : 'profiles'
	return 'http://steamcommunity.com/%s/%s/friends' % [path, URI::escape(name)]
end

# Returns the id/name of a user given a steam profile url.
# @param uri {String} full url of the steam profile page.
# @return {String} id/name of the user that the page belongs to.
def getNameByURL(uri)
	match = uri.to_str.match(/(?:profiles|id)\/(.*?)(?:$|\/)/);
	return match ? match[1] : match;
end

# Returns the friends of a given user.
# @param id {String} id/name of the user to retrieve the friends of.
# @return {Array} an array of strings that holds the id/names of the friends of the user.
def getFriends(id)
	uri = getURLByName(id)
	doc = Nokogiri::HTML(open(uri));
	return doc.css('a[class="friendBlockLinkOverlay"]').map{ |a| getNameByURL(a.attributes["href"]) };
end

# Generates a key/value mapping of users to friends, given an array of ids/names.
# @param ids {Array} an array of users to retrieve friends for.
# @return {Object} key/value mapping of user to his/her friends.
def createNetwork(ids)
	friends = {};
	ids.each{ |id|
		friends[id] = getFriends(id);
	}
	return friends
end

# Adds a given user to the given hashmap, if it already exists increments the counter.
def addToCommon(common, user)
	common[user] = 0 unless common.has_key? user
	common[user] += 1;
end

# Finds the commons friends of a given array of users.
# @param ids {Array} of users to get compare friends of.
# @return {Object} key/value map containing common friends, with a value of occurrence.
def findCommon(ids)
	commons, before_friends = {}, [];

	ids.each{|id|
		friends = getFriends(id);
		# For each friends array, we got before...
		before_friends.each{ |before|
			# Get intersection of current users friends and previous ones,
			# and insert them into the commons map.
			(before & friends).each{ |f| addToCommon(commons, f) };
		}
		# add this users friends to the previous friends array.
		before_friends.push(friends);
	};
	return commons;
end