Mission

Your mission, should you choose to accept it, is to build a microservice called shorty, which supports two URL shortening providers: bit.ly and tinyurl.com. You don't need to actually sign up to these providers, just implement their API. The service exposes a single endpoint: POST /shortlinks. The endpoint should receive JSON with the following schema:

param	type	required	description
url	string	Y	The URL to shorten
provider	string	N	The provider to use for shortening

The response should be a Shortlink resource containing:

param	type	required	description
url	string	Y	The original URL
link	string	Y	The shortened link

For example:

{
    "url": "https://example.com",
    "link": "https://bit.ly/8h1bka"
}

You are free to decide how to pick between the providers if one is not requested and what your fallback strategy is in case your primary choice fails. Your endpoint needs to return a JSON response with a sensible HTTP status in case of errors or failures.

Task

1. Create a Python env (using Python 3.6+) and install the requirements.
2. Build the POST /shortlinks endpoint. We've provided a skeleton API using flask.
3. Write some tests. We've provided a test blueprint using pytest.

Resources

1. Flask: http://flask.pocoo.org/
2. pytest: http://pytest.org/latest/
3. virtualenvwrapper: https://virtualenvwrapper.readthedocs.io/en/latest/
4. HTTP statuses: https://httpstatuses.com/

Implementation steps

1. bitly & tinyurl: Implemented tinyurl, bitly service classes, added a base class to combine them.
2. POST /shortlinks: Implemented the endpoint where the above classes are called based on user's input.
3. error handling: Implemented an error handler class and objects.
4. schema and provider control: Set up a default provider if none is chosen. Implemented fallback strategy.
5. unit testing: Functions are tested.
6. functional testing: Flask server is tested.
7. virtualenvwrapper: Script added.