Shorty Challenge

The trendy modern question for developer inteviews seems to be, "how to create an url shortner". Not wanting to fall too far from the cool kids, we have a challenge for you!

The Challenge

The challenge, if you choose to accept it, is to create a micro service to shorten urls, in the style that TinyURL and bit.ly made popular.

Build on Ubuntu

Ruby

$ sudo apt-get update
$ sudo apt-get install git-core curl git
$ command curl -sSL https://rvm.io/mpapis.asc | gpg --import -
$ curl -L https://get.rvm.io | bash -s stable
$ source ~/.rvm/scripts/rvm
$ rvm install 2.3.0
$ rvm use 2.3.0 --default
$ ruby -v
$ gem install bundler

Mongo

$ sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
$ echo "deb http://repo.mongodb.org/apt/ubuntu "$(lsb_release -sc)"/mongodb-org/3.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.0.list
$ sudo apt-get update
$ sudo apt-get install -y mongodb-org

MongoDB should start automatically. If not, run the following command:

$ sudo service mongod restart

Cloning the repo and starting the server

$ git clone https://github.com/frankieleef/shorty.git
$ cd shorty
$ bundle install
$ rackup # Or if you want to run it as a deamon, run rackup --daemonize

The server should start on http://localhost:3000

Testing

$ rspec

---

API Documentation

All responses must be encoded in JSON and have the appropriate Content-Type header

POST /shorten

POST /shorten
Content-Type: "application/json"

{
  "url": "http://example.com",
  "shortcode": "example"
}

Attribute	Description
url	url to shorten
shortcode	preferential shortcode

Returns:

201 Created
Content-Type: "application/json"

{
  "shortcode": :shortcode
}

A random shortcode is generated if none is requested, the generated short code has exactly 6 alpahnumeric characters and passes the following regexp: ^[0-9a-zA-Z_]{6}$.

Errors:

Error	Description
400	url is not present
409	The the desired shortcode is already in use. Shortcodes are case-sensitive.
422	The shortcode fails to meet the following regexp: ^[0-9a-zA-Z_]{4,}$.

GET /:shortcode

GET /:shortcode
Content-Type: "application/json"

Attribute	Description
shortcode	url encoded shortcode

Returns

302 response with the location header pointing to the shortened URL

HTTP/1.1 302 Found
Location: http://www.example.com

Errors

Error	Description
404	The shortcode cannot be found in the system

GET /:shortcode/stats

GET /:code
Content-Type: "application/json"

Attribute	Description
shortcode	url encoded shortcode

Returns

200 OK
Content-Type: "application/json"

{
  "startDate": "2012-04-23T18:25:43.511Z",
  "lastSeenDate": "2012-04-23T18:25:43.511Z",
  "redirectCount": 1
}

Attribute	Description
startDate	date when the url was encoded, conformant to ISO8601
redirectCount	number of times the endpoint GET /shortcode was called
lastSeenDate	date of the last time the a redirect was issued, not present if redirectCount == 0

Errors

Error	Description
404	The shortcode cannot be found in the system