Build a version controlled key-value store with a HTTP API we can query that from. The API needs to be able to:
Accept a key(string) and value(some json blob/string) {"key" : "value"} and store them. If an existing key is sent, the value should be updated
Accept a key and return the corresponding latest value
When given a key AND a timestamp, return whatever the value of the key at the time was.
Assume only GET and POST requests for simplicity.
Example:
Method: POST
Endpoint: /object
Body: JSON: {mykey : value1}
Time: 6.00 pm
Response: {"key":"mykey", "value":"value1", "timestamp": time } //Where time is timestamp of the post request (6.00pm) .
Method: GET
Endpoint: /object/mykey
Response: {"value": value1 }
Method: POST
Endpoint: /object
Body: JSON: {mykey : value2}
Time: 6.05 pm
Response: {"key":"mykey", "value":"value2", "timestamp": time } //Where time is timestamp of the new value (6.05pm) .
Method: GET
Endpoint: /object/mykey
Response: {"value": value2 }
Method: GET
Endpoint: /object/mykey?timestamp=1440568980 [6.03pm] // notice that the time here is not exactly 6.00pm
Response: {"value": value1 } // still return value 1 , because value 2 was only added at 6.05pm
All timestamps are unix timestamps according UTC timezone.
Guidelines:
Use NodeJS for scripting the backend.
Deploy this to a server and give us the URL
Push the code to a public git repository and give us the URL.
You are free to use any open source database.
A good submission will have the following characteristics:
Clean and extendable code
Handle a wide variety of edge cases
Not break under a reasonable load
Show knowledge of the various testing methodology
We are NOT judging for algorithmic brilliance or cool one liners. We want to see if you can write production quality code. So please build this assuming you are building a production quality service.