ivanjimenez / car-pooling

An API to manage car pooling

Car Pooling Service

At Car Polling we provide the service of taking people from point A to point B. So far we have done it without sharing cars with multiple groups of people. This is an opportunity to optimize the use of resources by introducing car pooling.

You have been assigned to build the car availability service that will be used to track the available seats in cars.

Cars have a different amount of seats available, they can accommodate groups of up to 4, 5 or 6 people.

People requests cars in groups of 1 to 6. People in the same group want to ride on the same car. You can take any group at any car that has enough empty seats for them. If it's not possible to accommodate them, they're willing to wait until there's a car available for them. Once a car is available for a group that is waiting, they should ride.

Once they get a car assigned, they will journey until the drop off, you cannot ask them to take another car (i.e. you cannot swap them to another car to make space for another group). In terms of fairness of trip order: groups are served in the order they arrive, but they ride opportunistically.

For example: a group of 6 is waiting for a car and there are 4 empty seats at a car for 6; if a group of 2 requests a car you may take them in the car for 6 but only if you have nowhere else to make them ride. This may mean that the group of 6 waits a long time, possibly until they become frustrated and leave.

API

To simplify the challenge and remove language restrictions, this service must provide a REST API which will be used to interact with it.

This API must comply with the following contract:

GET /status

Indicate the service has started up correctly and is ready to accept requests.

Responses:

• 200 OK When the service is ready to receive requests.

PUT /cars

Load the list of available cars in the service and remove all previous data (existing journeys and cars). This method may be called more than once during the life cycle of the service.

Body required The list of cars to load.

Content Type application/json

Sample:

[
  {
    "id": 1,
    "seats": 4
  },
  {
    "id": 2,
    "seats": 6
  }
]

Responses:

• 200 OK When the list is registered correctly.
• 400 Bad Request When there is a failure in the request format, expected headers, or the payload can't be unmarshalled.

POST /journey

A group of people requests to perform a journey.

Body required The group of people that wants to perform the journey

Content Type application/json

Sample:

{
  "id": 1,
  "people": 4
}

Responses:

• 200 OK or 202 Accepted When the group is registered correctly
• 400 Bad Request When there is a failure in the request format or the payload can't be unmarshalled.

POST /dropoff

A group of people requests to be dropped off. Whether they traveled or not.

Body required A form with the group ID, such that ID=X

Content Type application/x-www-form-urlencoded

Responses:

• 200 OK or 204 No Content When the group is unregistered correctly.
• 404 Not Found When the group is not to be found.
• 400 Bad Request When there is a failure in the request format or the payload can't be unmarshalled.

POST /locate

Given a group ID such that ID=X, return the car the group is traveling with, or no car if they are still waiting to be served.

Body required A url encoded form with the group ID such that ID=X

Content Type application/x-www-form-urlencoded

Accept application/json

Responses:

• 200 OK With the car as the payload when the group is assigned to a car.
• 204 No Content When the group is waiting to be assigned to a car.
• 404 Not Found When the group is not to be found.
• 400 Bad Request When there is a failure in the request format or the payload can't be unmarshalled.