Note 7/8/2013: Craigslist makes it impossible (please let me know if you were able to get around it) to allow Mechanize to retrieve HTML from Heroku’s server. However, it works when I send a request from my local server. If anyone knows why it would make a difference, please leave a comment!

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Anyone familiar with the SF apartment market understands the tremendous pain and frustrations in finding an available lease at a reasonable price. We have all heard and shared war stories of the hourly refreshing of Craigslist and bringing all of your bank statements and necessary paperwork to the open house just to win a chance to secure a lease for an apartment. In true SF-technology fashion, I decided to minimize response time to a new choice apartment listings on Craigslist by wiring together IFTTT, Mandrill, and Twilio to auto respond with an open email and a click-to-call to my phone number and the number in the listing to schedule an appointment.

IFTTT

IFTTT (‘If this, then that’) allows you to create ‘recipes’ using the simple conditional structure ‘If this, then that’ and various ‘ingredients‘ (i.e. craigslist queries, instagram posts, buzzfeed articles, tweets). It is powerful due to its simplicity and flexibility; it can enable anyone to put the web to work without any programming knowledge.

I used IFTTT to send an email to my email address when there is a new Craigslist query that matches the me and my roommates’ apartment listing preferences. This way, any new Craigslist listing that fits the query that I have set will be sent directly to my email inbox.

Mandrill

I setup a subdomain (I added ‘to’ as the MX record and have it setup on my Mandrill account) responsible to receiving email messages and use Mandrill to parse the inbound email (similar to how I built the A-List inbound parser). In the below code sample, it is important to note that you must first return a ‘200’ to let Mandrill know that it is the right address to send the POST request of the inbound email.

	require 'mechanize'

	class InboxController < ApplicationController
	include Mandrill::Rails::WebHookProcessor

	# For the apartment hunt.
	def parse_inbound_sf_apartment_email
	# Mandrill needs an ok in order to proceed to POST Mandrill events to this endpoint.
	if request.head?
	head :ok
	else
	# When receive new IFTTT email, use Mechanize to go to the URL of the listing.
	# Then get two things:
	# – anything that resembles a phone number
	# – a response email address
	# Afterwards, dial order for all roommates and connect w the broker
	# Then send a templatized email.

	if params['mandrill_events']
	text_body = ''
	JSON.parse(params['mandrill_events']).each do \|raw_event\|
	event = Mandrill::WebHook::EventDecorator[raw_event]
	text_body = event['msg']['text'].to_s
	end

	# Get the URL of the craigslist listing.
	url = text_body[/http\:(.*?)\.html/m]

	# Mechanize to get email address and phone number.
	a = Mechanize.new

	begin
	craigslist_listing = a.get(url.to_s)
	rescue ArgumentError
	# URL is not valid
	puts "\n\n\n\nURL IS NOT VALID\n\n\n\n"
	return "error"
	else
	# Regex to get email and phone number
	email_addresses = craigslist_listing.content.to_s.scan(/[\w.!#\$%+-]+@[\w-]+(?:\.[\w-]+)+/).uniq!
	phone_numbers = craigslist_listing.content.to_s.scan(/\W(\d{3}.?\d{3}.?\d{4})\W/m).uniq! – craigslist_listing.content.to_s.scan(/postingID=(.*?)\W/mi).uniq!

	# 'Click-to-call'.
	phone_numbers.each do \|phone_number\|
	# puts phone_number
	# Make outbound call to 314 (Andy, Jeff, whoever else).
	# Then, make outbound call to phone number.
	click_to_call(phone_number[0])
	end

	# Send templatized email to email_address.
	email_addresses.each do \|email_address\|
	Mailer.email_apartment_listing(email_address, 'Apartment listing').deliver
	end
	end
	end
	render 'app/views/inbox/sfapartments.html', :formats => [:html]
	end
	end
	end

view raw

inbox_controller.rb

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Once the email is successfully received and parsed, I use the Mechanize library to navigate to the Craigslist listing (line 31). Then, a few regex commands to find and scrape an email address (line 34) and a phone number (line 35). With the email address, I use ActionMailer (line 46) to send out a templatized email, cc’ing my roommates, asking to schedule an appointment to check out the apartment.

Twilio

If I was successfully able to scrape a phone number from the Craigslist listing, then Twilio will automatically make two outbound phone calls (one to my mobile phone and one to the number on the listing). Throughout the day, I will be able to pick up my phone at my leisure and speak with somebody (if the call connects on the other end) to schedule an appointment.

Note that the routing must also be setup in your Rails app (the sample code is not shown here).

The first step is that we are sending a request to Twilio to initiate a phone call to my phone number (agent_number or ‘555-555-5555’ in the example below) with dynamic TwiML (Twilio’s XML-like proprietary markup language).

	require 'twilio-ruby'

	class InboxController < ApplicationController
	BASE_URL = 'http://www.andyjiang.com/'

	# /click-to-call-request
	def click_to_call(calling_to)
	# debugging purposes.
	twilio_number = '4154444444'
	calling_to = digits_only(calling_to)

	agent_phone = '5555555555'
	caller_id = agent_phone

	# When we call the agent (andy + our apartment), we set the caller ID to the party we're eventually
	# calling. Why? So you could call them back from normal cellphone later.
	begin
	@client = Twilio::REST::Client.new ACCOUNT_SID, AUTH_TOKEN
	@client.account.calls.create(
	:from => twilio_number,
	:to => agent_phone,
	:url => BASE_URL + '/click-to-call-callscreen?calling_to=' + calling_to + '&caller_id=' + caller_id
	)
	puts "click to call initiated."
	rescue
	400
	end

	render 'app/views/inbox/sfapartments.html', :formats => [:html]
	end

	# /click-to-call-callscreen
	# This handler receives an HTTP callback from Twilio once the agent has picked up
	# their phone. It first verifies that they're ready to receive the call (to avoid
	# voicemail) and then defers to the final twiml URL.
	def click_to_call_callscreen
	@post_to = BASE_URL + '/click-to-call-twiml?calling_to=' + params['calling_to'] + '&caller_id=' + params['caller_id']
	render :action => 'clicktocallcallscreen.xml.builder', :layout => false
	end

	# /click-to-call-twiml
	# This handler is fired if the callscreen detected a digit
	def click_to_call_twiml
	@calling_to = params['calling_to']
	@caller_id = params['caller_id']
	render :action => 'clicktocall.xml.builder', :layout => false
	end

	def digits_only(string)
	return string.gsub(/[^[0-9]]/, "")
	end
	end

view raw

inbox_controller.rb

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The first dynamic TwiML (line 38 above and ‘clicktocallcallscreen.xml.builder’ below) tells Twilio to listen, upon a call connecting with my phone (agent_number or ‘555-555-5555’), for a keypad response indicating that I want to be connected with the Craigslist lister’s phone number. If I hit a key, then proceed to dial the other number and connect us. Note that I am providing yet another dynamic action URL (‘@post_to’) that will populate the final TwiML with the correct phone numbers that will be connected in the final call.

	xml.instruct!
	xml.Response do
	xml.Gather(:action => @post_to, :numDigits => 1, :timeout => '10') do
	xml.Say "Press a key to accept", :voice => :woman
	end
	xml.Say "You didn't press anything. Goodbye.", :voice => :woman
	xml.Hangup
	end

view raw

clicktocallcallscreen.xml.builder

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It is in line 46 in inbox_controller.rb where the clicktocall.xml.builder (below) is called dynamically (with ‘@calling_to’ and ‘@caller_id’ both being passed to the TwiML).

	xml.instruct!
	xml.Response do
	xml.Dial @calling_to, :callerId => @caller_id
	end

view raw

clicktocall.xml.builder

hosted with ❤ by GitHub

The result is Twilio automatically connecting me with the phone number listed on the Craigslist post. This is a derivation of a very popular Twilio use ‘Click-to-call’ that many lead management and sales teams use to better engage with their customers.

Conclusion

Now I don’t have to be on Craigslist 24/7 to find a suitable apartment listing; I can just wait for my web server to send out emails or phone calls to schedule appointments with Craigslist posts that fit our preferences. Now if there were only a way to automate the showing up, preparing the paper work, competing against other bidders, and the remainder of the apartment leasing process.

Andy

In person conversation is fleeting. Words hang in the air for a brief moment then vanish suddenly. All participating members have to be present and aware in order to keep up with the conversation.

Conversation online has traditionally been very asynchronous. Instant message and email both log your messages with a timestamp, allowing you to maintain a history conversations for you to browse afterwards. You can message your friend knowing that she probably won’t respond immediately.

Phantachat is an online chat web app, but tries to mimic chat in person. Your messages linger for no longer than a few seconds, forcing you to have that page open on your screen to be able to follow the conversation. Messages are also sent in immediate real time, without having you to hit enter, and there is no backspace.

Websockets

Websocket is a web technology providing simultaneous two-way communications channels over a single TCP connection. This allows for immediate, seamless, synchronous data passing between the client and the server. We decided that in order to get the chat to behave as real time as possible, that we would choose to use Websockets (we went with Socket.io with Node.js/Express.js).

Unfortunately, there are very few free web/application hosting services out there that support websockets. Heroku doesn’t support web sockets, but you can configure your application to instead use long polling, which allows the client to send HTTP requests to the server at regular intervals and immediately receives a response.

Some other hosting platforms out there (www.appfog.com, http://www.dotcloud.com, http://www.nodejitsu.com) may support web sockets, but unfortunately they don’t provide a free tier. Our next plans are to spin up an instance on AWS so we can deploy a solution that uses websockets instead of long polling.

Dynamic chat rooms

In order to generate a unique chatroom, we created added some logic to the routing: if someone goes to the root, then generate a new hash (I used the hashids package for generating codes) and redirect to the new route with the hash at the end and start a new socket.io namespace; if someone goes to a hash that exists, then throw that person into the same socket.io namespace; and if someone goes to a route that is a hash that doesn’t exist, the server will return an error page.

With socket.io, there are two main ways of creating ‘chatrooms’: using ‘rooms’ or using ‘namespacing’. We decided to use namespacing, because namespaces can be connected to by the client (but only if it already exists on the server). With rooms, they can only be joined on the server side.

When a new namespace is created (when a new hash is generated on the server), the server creates a new namespace, then passes the hash to the client to allow the client to join that specific namespace.

Next Steps

This is still a very simple app. Next steps could be sharing other types of media that will also vanish within a few seconds (images, for instance). Or to allow more than two people to join each chat room (right now, it is only one on one).

Suggestions, feedback, and new ideas are always welcome!

Github: https://github.com/lambtron/phantachat

Andy

andy jiang

post-corporate

Monthly Archives: June 2013

How IFTTT, Mandrill, and Twilio is helping me find an apartment in SF