Sample Problem

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The Application

Build an API that allows a user to enter a date time range and get back the price at which they would be charged to park for that time span.

API Endpoints

• The application publishes an API with two endpoints that computes a price for an input datetime range.
• The API must respond to requests on port 5000
• The API must respond using JSON

Rates

The first endpoint is rates.

This path takes a PUT where rate information can be updated by submitting a modified rates JSON. This submitted JSON overwrites the stored rates.

• A rate is comprised of a price, time range the rate is valid, and days of the week the rate applies to
• See the section Sample JSON for testing for the initial set of seeded rates. These rates are expected to be loaded into the database at application startup.

This path when requested with a GET returns the rates stored.

Price

The second endpoint is price. It allows the user to request the price for a requested time.

• It uses query parameters for requesting the price
• The user specifies input date/times as ISO-8601 with timezones
• The paramters are start and end.
• An example query is ?start=2015-07-01T07:00:00-05:00&end=2015-07-01T12:00:00-05:00
• Response contains price

  • {
       "price": 5000
    }
    

Response Requirements

• User input can span more than one day, but the API mustn't return a valid price - it must return "unavailable"
• User input can span multiple rates, but the API mustn't return a valid price - it must return "unavailable"
• Rates will not span multiple days

Application startup

Rates are specified by a JSON file to be automatically loaded on start of the application. The format of this file is the same JSON structure that can be submitted to the rates endpoint. The values for these rates can be found in the Sample JSON for testing section below.

Other Requirements

• There must be documentation that one can follow to run the application
• API endpoints must be clearly documented
• Tests need to be in place
• We will be running automated requests against your submission. Please take care to follow the requirements laid out.
• Preferred languages are Python, Kotlin, Java, or Go but may vary from squad to squad
  • Please let the recruiting team know your language of choice

Submitting

• Zip up your submission and submit it via GreenHouse
  • You can achieve this with git archive --format zip --output /full/path/to/zipfile.zip master if using git
• Include any instructions on how to build, run, and test your application

Sample JSON for testing

{
    "rates": [
        {
            "days": "mon,tues,thurs",
            "times": "0900-2100",
            "tz": "America/Chicago",
            "price": 1500
        },
        {
            "days": "fri,sat,sun",
            "times": "0900-2100",
            "tz": "America/Chicago",
            "price": 2000
        },
        {
            "days": "wed",
            "times": "0600-1800",
            "tz": "America/Chicago",
            "price": 1750
        },
        {
            "days": "mon,wed,sat",
            "times": "0100-0500",
            "tz": "America/Chicago",
            "price": 1000
        },
        {
            "days": "sun,tues",
            "times": "0100-0700",
            "tz": "America/Chicago",
            "price": 925
        }
    ]
}

The timezones specified in the JSON file adhere to the current version of the tz database. Assume that there could be other (non America/Chicago) timezones specified. For more information: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones

Assume that rates in this file will never overlap

Sample result

Datetime ranges must be specified in ISO-8601 format. A rate must completely encapsulate a datetime range for it to be available.

• 2015-07-01T07:00:00-05:00 to 2015-07-01T12:00:00-05:00 must yield {'price': 1750}
• 2015-07-04T15:00:00+00:00 to 2015-07-04T20:00:00+00:00 must yield {'price': 2000}
• 2015-07-04T07:00:00+05:00 to 2015-07-04T20:00:00+05:00 must yield "unavailable"

Assessment

Members of our backend team will ensure your code meets the functional criteria and score the submission based on project design, language/framework best practices, code cleanliness and organization, ease of use, packaging, documentation, and testing practices.