为两点之间的路径设计WebService API

Question

I have a Web Service which returns details of path between given two input points if exists. The Web Service API is something like getPath(Point start,Point end). Now if the path doesn't exist between given start & end points, how should API behave among below options

1. Return a null object
2. Throw a PathNotFoundException
3. Always include a status code in the response along with path details. In this case return empty path and status code as appropriate error code like "PATH_NOT_FOUND" / "ERROR"
4. Any other option? Please suggest.

Please let me know your views

Thanks, Harish

Answer 1

Suggestion: 1. return null or empty path.

Throwing exceptions across http is probably not the best idea and returning status codes is a way to workaround throwing exceptions. The lack of a path is not something that should occur as error at the client side.

I would reserve exceptions/status codes for wrong parameters, wrong number of parameters, some server-side problems like inaccessible database etc.

Suppose you are querying the database for a list of customers from NY. Would you throw an exception if the list is empty or just return an empty list? This sounds exactly like your scenario.