Write an HTTP service that exposes an endpoint "/numbers". This endpoint receives a list of URLs though GET query parameters. The parameter in use is called "u". It can appear more than once.

https://yourserver:8080/numbers?u=https://example.com/primes&u=https://foobar.com/fibo

When the /numbers is called, your service shall retrieve each of these URLs if they turn out to be syntactically valid URLs. Each URL will return a JSON data structure that looks like this:

{ "numbers": [ 1, 2, 3, 5, 8, 13 ] }

The JSON data structure will contain an object with a key named "numbers", and a value that is a list of integers. After retrieving each of these URLs, the service shall merge the integers coming from all URLs, sort them in ascending order, and make sure that each integer only appears once in the result. The endpoint shall then return a JSON data structure like in the example above with the result as the list of integers.

The endpoint needs to return the result as quickly as possible, but always within 500 milliseconds. It needs to be able to deal with error conditions when retrieving the URLs. If a URL takes too long to respond, it must be ignored. It is valid to return an empty list as result only if all URLs returned errors or took too long to respond. The timeout must be respected regardless of the size of the data.

The service receives an HTTP request:

>>> GET /numbers?u=https://example.com/primes&u=https://foobar.com/fibo HTTP/1.0

It then retrieves the URLs specified as parameters.

The first URL returns this response:

>>> GET /primes HTTP/1.0
>>> Host: example.com
>>>
<<< HTTP/1.0 200 OK
<<< Content-Type: application/json
<<< Content-Length: 34
<<<
<<< { "numbers": [ 2, 3, 5, 7, 11, 13 ] }

The second URL returns this response:

>>> GET /fibo HTTP/1.0
>>> Host: foobar.com
>>>
<<< HTTP/1.0 200 OK
<<< Content-Type: application/json
<<< Content-Length: 40
<<<
<<< { "numbers": [ 1, 1, 2, 3, 5, 8, 13, 21 ] }

The service then calculates the result and returns it.

<<< HTTP/1.0 200 OK
<<< Content-Type: application/json
<<< Content-Length: 44
<<<
<<< { "numbers": [ 1, 2, 3, 5, 7, 8, 11, 13, 21 ] }

As a reference, you will be provided with an tiny golang app that, when run, listens on port 8090 and provides the endpoints /primes, /fibo, /odd and /rand.

To improve your experience additional remote server will be provided to you. The same server will be later used by us to evaluate the solution. It exposes single endpoint /numbers that can be used in a similar way like ones provided by the reference. This endpoint in its behaviour is trying to mimic real-world application. Different payload sizes, status codes and response times can be expected.