Question

I am developing a web api using WCF Web Api preview 5. At the moment I have a resource class fully functional, how ever I noticed my methods inside this resouce are getting complex.

For example:

[WebInvoke(UriTemplate = "{EhrID}/PhysicalTest",Method="POST")]
    public HttpResponseMessage<DTO.PhysicalTest> PostPhysicalTest(int EhrID, DTO.PhysicalTest PhysicalTestDTO)
    {
        var EHR = repository.FindById(EhrID);
        var PhysicalTest = Mapper.Map<DTO.PhysicalTest, PhysicalTest>(PhysicalTestDTO);

        if (PhysicalTest == null)
        {                
            var response = CreateResponseForException("No object to store", HttpStatusCode.BadRequest);
            throw new HttpResponseException(response);
        }

        try
        {
            if (EHR.PhysicalTests == null)
            {
                EHR.PhysicalTests = new List<PhysicalTest>();
            }
            PhysicalTest.CreationDate = DateTime.Now;
            EHR.PhysicalTests.Add(PhysicalTest);
            _unitOfWork.Commit();
            return new HttpResponseMessage<DTO.PhysicalTest>(PhysicalTestDTO, HttpStatusCode.Created);
        }
        catch (Exception ex) {                
            var response = CreateResponseForException("Cannot create Physical Test", HttpStatusCode.InternalServerError);
            throw new HttpResponseException(response);
        }
    }

As you may notice this method has the task of posting a new Physical Test, but it’s actually validating my model too (I’m missing lots of validations still, property validations), which should not be this class concern. If there any approachable way to reduce the complexity of the methods inside de resource?

Answer 1

I would split it up into smaller more focused methods. I might also start using instance variables instead of passing all these arguments around, but for the sake of this post I’ve rewritten it without pushing stuff to instance variables.

[WebInvoke(UriTemplate = "{EhrID}/PhysicalTest",Method="POST")] 
public HttpResponseMessage<DTO.PhysicalTest> PostPhysicalTest(int EhrID, DTO.PhysicalTest PhysicalTestDTO) 
{ 
    var EHR = repository.FindById(EhrID); 
    var PhysicalTest = Mapper.Map<DTO.PhysicalTest, PhysicalTest>(PhysicalTestDTO); 

    if (PhysicalTest == null) 
    {                 
        var response = CreateResponseForException("No object to store", HttpStatusCode.BadRequest); 
        throw new HttpResponseException(response); 
    } 

    PostPhysicalTest(EHR, PhysicalTest);
    return new HttpResponseMessage<DTO.PhysicalTest>(PhysicalTestDTO, HttpStatusCode.Created);
}

private void PostPhysicalTest(EHR ehr, PhysicalTest physicalTest)
{
    try 
    { 
        CreatePhysicalTest(ehr, physicalTest);
    } 
    catch (Exception ex) {                 
        var response = CreateResponseForException("Cannot create Physical Test", HttpStatusCode.InternalServerError); 
        throw new HttpResponseException(response); 
    }
}

private void CreatePhysicalTest(EHR ehr, PhysicalTest physicalTest)
{
    if (ehr.PhysicalTests == null) 
    { 
        ehr.PhysicalTests = new List<PhysicalTest>(); 
    }

    physicalTest.CreationDate = DateTime.Now; 
    ehr.PhysicalTests.Add(physicalTest); 
    _unitOfWork.Commit();
}