Post method exceptions with "if else" statments optimization and json object improvemnt

Question

I would like to know how to know how can I optimize my current Post method , I initialize object where I am creating list of json items. Also how can I reduce many if and if else statments? For this post and get methods I am using swagger , is it possible to declare exceptions objects somewhere globaly? What kind of good practice there is regarding swagger objects, maybe I have to declare somewhere as json structure?

[HttpPost]
        public IHttpActionResult Post([FromBody] SpecCaseRequest specCaseRequest)
        {
            var specCase= new SpecCase();

            specCase.CopyFromRequest(specCaseRequest);

            ExceptionResponse[] data = new ExceptionResponse[]
            {
                new ExceptionResponse { Id = 1, Message = "some text", ReturnCode = HttpStatusCode.BadRequest },
                new ExceptionResponse { Id = 2, Message = "some text", ReturnCode = HttpStatusCode.BadRequest },
                new ExceptionResponse { Id = 3, Message = "some text", ReturnCode = HttpStatusCode.Created },
                new ExceptionResponse { Id = 4, Message = "some text", ReturnCode = HttpStatusCode.BadRequest },
                new ExceptionResponse { Id = 5, Message = "some text", ReturnCode = HttpStatusCode.BadRequest },
                new ExceptionResponse { Id = 7, Message = "some text", ReturnCode = HttpStatusCode.BadRequest },
            };

            string json = JsonConvert.SerializeObject(data, Formatting.Indented);

            JArray jo = JArray.Parse(json);
            HttpResponseMessage responseMsg2 = new HttpResponseMessage(HttpStatusCode.BadRequest);   

            if (specCase.Name == "")
            {
                JObject match = jo.Values<JObject>()
                    .Where(m => m["Id"].Value<int>() == 2)
                    .FirstOrDefault();
                responseMsg2.Headers.Location = new Uri(Url.Link("DefaultApi", new { controller = "SpecCases", id = specCase.Id }));
                responseMsg2.Content = new StringContent(match.ToString(), Encoding.UTF8, "application/json");
                responseMsg2.Content.ReadAsStringAsync();
                IHttpActionResult response2 = ResponseMessage(responseMsg2);
                return response2;
            }
            else if (specCase.Name == null)
            {
                JObject match = jo.Values<JObject>()
                    .Where(m => m["Id"].Value<int>() == 1)
                    .FirstOrDefault();
                responseMsg2.Headers.Location = new Uri(Url.Link("DefaultApi", new { controller = "SpecCases", id = specCase.Id }));
                responseMsg2.Content = new StringContent(match.ToString(), Encoding.UTF8, "application/json");
                responseMsg2.Content.ReadAsStringAsync();
                IHttpActionResult response2 = ResponseMessage(responseMsg2);
                return response2;
            }
            else if (specCase.Signatories.Select(x => x.SignatoryId == "" && x.Type == SignatoryType.Company).FirstOrDefault())
            {
                JObject match = jo.Values<JObject>()
                    .Where(m => m["Id"].Value<int>() == 4)
                    .FirstOrDefault();
                responseMsg2.Headers.Location = new Uri(Url.Link("DefaultApi", new { controller = "SpecCases", id = specCase.Id }));
                responseMsg2.Content = new StringContent(match.ToString(), Encoding.UTF8, "application/json");
                responseMsg2.Content.ReadAsStringAsync();
                IHttpActionResult response2 = ResponseMessage(responseMsg2);
                return response2;
            }
            else if (specCaseRequest.Signatories.Select(x => x.Type != SignatoryType.Company).FirstOrDefault()) 
            {
                JObject match = jo.Values<JObject>()
                    .Where(m => m["Id"].Value<int>() == 8)
                    .FirstOrDefault();
                responseMsg2.Headers.Location = new Uri(Url.Link("DefaultApi", new { controller = "SpecCases", id = specCase.Id }));
                responseMsg2.Content = new StringContent(match.ToString(), Encoding.UTF8, "application/json");
                responseMsg2.Content.ReadAsStringAsync();
                IHttpActionResult response2 = ResponseMessage(responseMsg2);
                return response2;
            }
            else if (specCaseRequest.Signatories.Select(x => x.Id == "").FirstOrDefault()) 
            {
                JObject match = jo.Values<JObject>()
                    .Where(m => m["Id"].Value<int>() == 9)
                    .FirstOrDefault();
                responseMsg2.Headers.Location = new Uri(Url.Link("DefaultApi", new { controller = "SpecCases", id = specCase.Id }));
                responseMsg2.Content = new StringContent(match.ToString(), Encoding.UTF8, "application/json");
                responseMsg2.Content.ReadAsStringAsync();
                IHttpActionResult response2 = ResponseMessage(responseMsg2);
                return response2;
            }
            else if (specCase.Signatories.Select(x => x.SignatoryId == null).FirstOrDefault())
            {
                JObject match = jo.Values<JObject>()
                    .Where(m => m["Id"].Value<int>() == 5)
                    .FirstOrDefault();
                responseMsg2.Headers.Location = new Uri(Url.Link("DefaultApi", new { controller = "SpecCases", id = specCase.Id }));
                responseMsg2.Content = new StringContent(match.ToString(), Encoding.UTF8, "application/json");
                responseMsg2.Content.ReadAsStringAsync();
                IHttpActionResult response2 = ResponseMessage(responseMsg2);
                return response2;
            }
            else if (specCase.Signatories.Select(x => x.SignatoryId == "").FirstOrDefault())
            {
                JObject match = jo.Values<JObject>()
                    .Where(m => m["Id"].Value<int>() == 7)
                    .FirstOrDefault();
                responseMsg2.Headers.Location = new Uri(Url.Link("DefaultApi", new { controller = "SpecCases", id = specCase.Id }));
                responseMsg2.Content = new StringContent(match.ToString(), Encoding.UTF8, "application/json");
                responseMsg2.Content.ReadAsStringAsync();
                IHttpActionResult response2 = ResponseMessage(responseMsg2);
                return response2;
            }

            try
            {
                var specCaseRequest= unitOfWork.GetSigningCaseRepository();
                specCaseRequest.Add(specCase);
                unitOfWork.Save();
            }
            catch (Exception e)
            {
                Log.Error(e.Message);
                return InternalServerError();
            }

            JObject match1 = jo.Values<JObject>()
                    .Where(m => m["Id"].Value<int>() == 3)
                    .FirstOrDefault();

            HttpResponseMessage responseMsg = new HttpResponseMessage(HttpStatusCode.Created);
            responseMsg.Headers.Location = new Uri(Url.Link("DefaultApi", new { controller = "SpecCases", id = specCase.Id }));
            responseMsg.Content = new StringContent(match1.ToString(), Encoding.UTF8, "application/json");
            responseMsg.Content.ReadAsStringAsync();
            IHttpActionResult response = ResponseMessage(responseMsg);

            return response;
        }

Answer 1

Instead of combining Where + FirstOrDefault you can simply call FirstOrDefault as it accepts predicates as well example:

JObject match1 = jo.Values<JObject>()
    .Where(m => m["Id"].Value<int>() == 3)
    .FirstOrDefault();

Like this:

JObject match1 = jo
    .Values<JObject>()
    .FirstOrDefault(m => m["Id"].Value<int>() == 3);

Next I would suggest to create a dictionary which contains all of your if statements as keys and the values will be they're respective values 1,2,4,5...

This will allow you to make your method really short:

public IHttpActionResult Post(SpecCaseRequest specCaseRequest)
{
    var specCase = new SpecCase();

    specCase.CopyFromRequest(specCaseRequest);

    ExceptionResponse[] data = new ExceptionResponse[]
    {
        new ExceptionResponse { Id = 1, Message = "some text", ReturnCode = HttpStatusCode.BadRequest },
        new ExceptionResponse { Id = 2, Message = "some text", ReturnCode = HttpStatusCode.BadRequest },
        new ExceptionResponse { Id = 3, Message = "some text", ReturnCode = HttpStatusCode.Created },
        new ExceptionResponse { Id = 4, Message = "some text", ReturnCode = HttpStatusCode.BadRequest },
        new ExceptionResponse { Id = 5, Message = "some text", ReturnCode = HttpStatusCode.BadRequest },
        new ExceptionResponse { Id = 7, Message = "some text", ReturnCode = HttpStatusCode.BadRequest },
    };

    string json = JsonConvert.SerializeObject(data, Formatting.Indented);

    JArray jo = JArray.Parse(json);
    var badRequests = new Dictionary<Func<bool>, int?>
    {
        [() => specCase.Name == null] = 1,
        [() => specCase.Name == ""] = 2,
        [() => specCase.Signatories.Select(x => x.SignatoryId == "" && x.Type == SignatoryType.Company)
            .FirstOrDefault()] = 4,
        [() => specCase.Signatories.Select(x => x.SignatoryId == null).FirstOrDefault()] = 5,
        [() => specCase.Signatories.Select(x => x.SignatoryId == "").FirstOrDefault()] = 7,
        [() => specCaseRequest.Signatories.Select(x => x.Type != SignatoryType.Company).FirstOrDefault()] = 8,
        [() => specCaseRequest.Signatories.Select(x => x.Id == "").FirstOrDefault()] = 9,
    };
    HttpResponseMessage responseMsg;
    JObject match;
    int? value = badRequests.FirstOrDefault(kvp => kvp.Key.Invoke()).Value;
    if (value != null)
    {
        match = jo
            .Values<JObject>()
            .FirstOrDefault(m => m["Id"].Value<int>() == value);
        responseMsg = new HttpResponseMessage(HttpStatusCode.BadRequest);
    }
    else
    {
        match = jo
            .Values<JObject>()
            .FirstOrDefault(m => m["Id"].Value<int>() == 3);
        responseMsg = new HttpResponseMessage(HttpStatusCode.Created);
    }

    responseMsg.Headers.Location = new Uri(Url.Link("DefaultApi", new { controller = "SpecCases", id = specCase.Id }));
    responseMsg.Content = new StringContent(match.ToString(), Encoding.UTF8, "application/json");
    responseMsg.Content.ReadAsStringAsync();
    IHttpActionResult response = ResponseMessage(responseMsg);

    return response;
}

Answer 2

This one method is 120+ lines long -- and this is just one method in your controller! That alone should have informed you that you should extract this to a separate class. Keep your controller lean, which is easy to achieve with (for instance) MediatR.

---

Names are important: data tells me nothing. Ditto jo. Ditto responseMsg2. Ditto response2. Ditto match1.

Or consider var specCaseRequest= unitOfWork.GetSigningCaseRepository();: it doesn't make sense to me that the method GetSigningCaseRepository results in a variable called specCaseRequest.

What is ResponseMessage()? Looks like you use it as a method -- IHttpActionResult response2 = ResponseMessage(responseMsg2); -- yet its name sounds like a class name.

---

Instead of "", use string.Empty, e.g. in if (specCase.Name == "").

---

You seem to have copy-pasted this almost a dozen times, even though there are only minor differences between each version:

JObject match = jo.Values<JObject>()
    .Where(m => m["Id"].Value<int>() == 2)
    .FirstOrDefault();
responseMsg2.Headers.Location = new Uri(Url.Link("DefaultApi", new { controller = "SpecCases", id = specCase.Id }));
responseMsg2.Content = new StringContent(match.ToString(), Encoding.UTF8, "application/json");
responseMsg2.Content.ReadAsStringAsync();
IHttpActionResult response2 = ResponseMessage(responseMsg2);
return response2;

Do not copy-paste; instead move such lines to a method with the appropriate parameters.

---

I find it a bit odd that you make a distinction between if (specCase.Name == "") and if (specCase.Name == null).

Ditto for x.SignatoryId == null and x.SignatoryId == "".

Meanwhile you only check specCaseRequest.Signatories.Select(x => x.Id == "") and not specCaseRequest.Signatories.Select(x => x.Id == null).

Answer 3

First off, it is generally considered bad practice to create and use global variables. You could probably combine a few of the elif statements. You could also use case (if that language has it) but that is not too much better.