Add method to get URL Status (returns an URLItem)

[klockla]

Add a new API method to retrieve information about an URL

 /** Get status of a particular URL 
     This does not take into account URL scheduling.
     Used to check current status of an URL within the frontier
 **/
 rpc GetURLStatus(URLStatusRequest) returns (URLItem) {}

Implemented only for MemoryFrontier and RocksDb
(may fullfill partially #57 )

Unfortunately the internal storage doesn't make a distinction between Discovered and Known URLs which have to be refetched (or I have missed the point)

So all scheduled items will be returned as a KnownURLItem (with a refetch date equal to 0 for completed items)
If the URL is not in URLFrontier, the method will return io.grpc.Status.NOT_FOUND.asRuntimeException()

Signed-off-by: Laurent Klock [email protected]

[jnioche]

A few minor issues and questions. Great to have additional tests!

[jnioche]

Thanks @klockla
Looks good at this stage but I think it needs an addition to the client so that we can query the new endpoint and display the status of a URL.

[jnioche]

see comment in the conversation re-client side

[klockla]

see comment in the conversation re-client side

Added the method in client.

[jnioche]

see comment about key being generated by default on the server side. Should be optional?

[klockla]

ok

[jnioche]

thanks a lot @klockla - I gave it a try and it seems to work fine
let me know what you think of my comments and suggestions above

[jnioche]

Tested, works great! Thanks @klockla, this is a great contribution to the project