Switching from sync to async APS.NET API controller - c#

I have this C# controller which preforming a different SQL functions by string receive as input.
public HttpResponseMessage GetFunction(string SQLstring)
{
HttpResponseMessage response = new HttpResponseMessage()
{
Content = new StringContent(SQLFunctions.SQLsyncFunctionGet(SQLstring), System.Text.Encoding.UTF8, "application/json")
};
return response;
}
I'm trying to rebuild it in Async method:
First I change the SQL sync function to async without any problem:
public async Task<string> SQLasyncFunctionGET(string SQLString)
How do I change the GetFunction class to activate it in the Web API that I've built?
public async Task<IHttpActionResult> GetFunction(string SQLString)
{
var content = await ???????????????
return ok(content);
}

I'm not that familiar with this stack, so I don't remember if you can return Task<HttpResponseMessage> or not. But if you can, this should work:
public async Task<HttpResponseMessage> GetFunction(string SQLstring)
{
HttpResponseMessage response = new HttpResponseMessage()
{
Content = new StringContent(await SQLFunctions.SQLsyncFunctionGet(SQLstring), System.Text.Encoding.UTF8, "application/json")
};
return response;
}

Related

Serialize async response from a database client

I have an endpoint which is used to create an item. The controller calls the service which creates the item, makes some changes on the db and db returns data based on the procedure. The db returns a json like response, but is not always the same, so I have to adjust on the backend so that I can formalize the response type.
The problem is that create item service is asynchronous and I need to be able to await the response so I can make a new response based on that. How can I await the response and that I get from db client and then return data based on that.
This is my Action and I want to be able to serialize async response from service
[HttpPost]
public IActionResult CreateItem([FromBody] InputModel item)
{
var jsonString = _itemService.CreateItem(item);
ResponseModel? response = JsonSerializer.Deserialize<ResponseModel>(jsonString);
return new ObjectResult(response.Response) { StatusCode = response.StatusCode };
}
The default response model
public class ResponseModel
{
public string Response { get; set; }
public int StatusCode { get; set; }
}
Create Item service, which makes the post request to the client and it has to be async.
Depending on the status code that is coming from the client, I want to be able to set my action status code as well.
public async Task<string> CreateItem(InputModel item)
{
if (item.VersionType != 1)
{
return new { Response = "Incorrect data", StatusCode = 400 }.ToString()!;
}
var json = JsonSerializer.Serialize(item);
var data = new StringContent(json, Encoding.UTF8, "application/json");
var response = await client.PostAsync(url, data);
var content = await response.Content.ReadAsStringAsync();
return content;
}
You can make your action method async and then await the method call _itemService.CreateItem for it :
[HttpPost]
public async Task<IActionResult> CreateItem([FromBody] InputModel item)
{
var jsonString = await _itemService.CreateItem(item);
ResponseModel? response = JsonSerializer.Deserialize<ResponseModel>(jsonString);
return new ObjectResult(response.Response) { StatusCode = response.StatusCode };
}
Now your action method would asyncrounously wait for the result from CreateItem and when it returs result, it will continue executing further and send the deserialized response back to client.

How to capture IActionResult in c#

I have built an api caller which, for post requests, handles an input and output object:
public static async Task<TResponse> CallPostWebApi<TRequest, TResponse>(TRequest request, TResponse response, string serviceUrl)
{
using var client = new HttpClient { BaseAddress = new Uri(serviceUrl) };
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
var json = JsonConvert.SerializeObject(request);
var formData = new StringContent(json, Encoding.UTF8, "application/json");
var result = await client.PostAsync(serviceUrl, formData);
if (!result.IsSuccessStatusCode)
{
return response;
}
var data = await result.Content.ReadAsStringAsync();
return JsonConvert.DeserializeObject<TResponse>(data);
}
my api now returns an IActionResult with the object within it:
[HttpPost]
[ProducesResponseType(StatusCodes.Status200OK)]
[ProducesResponseType(StatusCodes.Status404NotFound)]
[Route("[Action]")]
public IActionResult MethodName(MyModel model)
{
try
{
var result = _reqRepo....
if (result.HasError)
{
return NotFound(result);
}
return Ok(result);
}
catch (Exception exception)
{
return NotFound(exception.Message);
}
}
when I call it though I don't know what to set as the return object
[HttpPost("[Action]")]
public async Task<IActionResult> SubmitConnectionToBilling(ConnectionModel model)
{
return await ApiCaller.CallPostWebApi(model, **???**,
_billingApiUrl + "/MyMethod");
}

Get & Post in ASP.NET Blazor

With the help of a few samples available on the internet, I am able to develop a ASP.NET Core Hosted Blazor Application.
But While Calling an api as follow
private async Task Refresh()
{
li.Clear();
li = await Http.GetJsonAsync<SampleModel[]>("/api/Sample/GetList");
StateHasChanged();
}
private async Task Save()
{
await Http.SendJsonAsync(HttpMethod.Post, "api/Sample/Add", obj);
await Refresh();
}
In the line below:
await Http.SendJsonAsync(HttpMethod.Post, "api/Sample/Add", obj);
How can I check status code of this HTTP call?
If there occurs any problem in API call than I want to display a message.
But when I do:
HttpResponseMessage resp = await Http.SendJsonAsync(HttpMethod.Post, "api/Sample/Add", obj);
Then it says:
can not cast void to HttpResponse Message
I am using below methods:
GetJsonAsync() // For HttpGet
SendJsonAsync() // For HttpPost And Put
DeleteAsync() // For HttpDelete
How can I verify the status code here ?
The thing is that you are using blazor's HttpClientJsonExtensions extensions,
Which internally usually calls
public static Task SendJsonAsync(this HttpClient httpClient, HttpMethod method, string requestUri, object content)
=> httpClient.SendJsonAsync<IgnoreResponse>(method, requestUri, content);
public static async Task<T> SendJsonAsync<T>(this HttpClient httpClient, HttpMethod method, string requestUri, object content)
{
var requestJson = JsonUtil.Serialize(content);
var response = await httpClient.SendAsync(new HttpRequestMessage(method, requestUri)
{
Content = new StringContent(requestJson, Encoding.UTF8, "application/json")
});
if (typeof(T) == typeof(IgnoreResponse))
{
return default;
}
else
{
var responseJson = await response.Content.ReadAsStringAsync();
return JsonUtil.Deserialize<T>(responseJson);
}
}
The GET requests use HttpContext.GetStringAsync internally
public static async Task<T> GetJsonAsync<T>(this HttpClient httpClient, string requestUri)
{
var responseJson = await httpClient.GetStringAsync(requestUri);
return JsonUtil.Deserialize<T>(responseJson);
}
while the normal HttpClient API still exists and can be used just as in those extension methods.
Those extension methods simply wrap the default HttpClient calls.
If you desire to have access to response status you would need to write your own wrappers that expose the desired functionality or just use the default API
Try this:
var response = await Http.SendJsonAsync <HttpResponseMessage>(HttpMethod.Post, "api/Sample/Add", obj);

MSUnit Testing Async Hell

I have an async Task unit test (MVC, c#, .NET 4.5.2). It does an await on a aysnc Task<ActionResult> method, which in turn has an await call on a async method.
The test, and others like it, will pass if I select them and choose Debug Selected Tests from the right-click menu in Visual Studio 2017.
The problem is when I select Run Selected Tests or Run All. It is then that many of the tests will fail if they follow the condition mentioned at the beginning. Any test that only returns a RedirectToRouteResult without having gone the aforementioned drill-down will pass.
[TestMethod]
public async Task TestPartsController_GetPartInfo_ReturnsInfo()
{
//arrange
PartController pc = new PartController();
//act
var result = await pc.GetPartInfo("PC123456");
//assert
Assert.IsIntanceOfType(result, typeof(ViewResult));
Assert.AreEqual("Form", ((ViewResult)result).ViewName);
Assert.AreEqual("PC123456", result.Model.PartNum.ToUpper());
}
public async Task<ActionResult> GetPartInfo(string partNum)
{
if (string.IsNullOrEmpty(partNum)
{
return RedirectToAction("Index")
}
var response = await ServiceClient.GetJsonAsync("/part/partinfo", "?partNum=" + partNum;
response.EnsureSuccessStatusCode();
results = await response.Content.ReadAsAsync<Dto.PartNumInfo>();
...
return View("Form", model);
}
public async Task<HttpResponseMessage> GetAsync(Controllers controller, string criteria)
{
HttpClient client;
string service = GetService(controller, out client);
var response = await client.GetAsync(service + criteria);
return response;
}
Solution
Use async/await all the way through as well as using statements and IDisposable.
public async Task<HttpResponseMessage> GetJsonAsync<T>(Controllers controller, T data)
{
HttpResponseMessage response;
using (var service = new MyService())
{
HttpClient http;
string serviceLoc = service.GetServiceClient(controller, out http);
response = await http.GetAsync(serviceLoc, data);
}
return response;
}
Solution Use async/await all the way through as well as using statements and IDisposable.
public async Task<HttpResponseMessage> GetJsonAsync<T>(Controllers controller, T data)
{
HttpResponseMessage response;
using (var service = new MyService())
{
HttpClient http;
string serviceLoc = service.GetServiceClient(controller, out http);
response = await http.GetAsync(serviceLoc, data);
}
return response;
}

ObjectDisposedException when reading requests HttpContent in test

I'm integrating a 3rd part API using TDD, and so I am implementing a HttpClient wrapper interface that exposes the possible api calls and so on.
I want to test that the correct payload was sent in a post method, but when I try to read the string content from my injected fake HttpMessageHandler I get an ObjectDisposedException. Is there a better way to test this?
Test code:
[Fact]
public async void PostSignupRequest_RequestSent_PostedSerializedRequestAsContent()
{
var client = MakeOnboardingClient();
_fakeJsonSerializer.SerializedResult = "some json";
await client.PostSignupRequest(_someSignupRequest);
Assert.Equal("some json", await _fakeMessageHandler.Request.Content.ReadAsStringAsync());
}
My HttpMessageHandler spy/test double:
public class FakeHttpMessageHandler : HttpMessageHandler
{
public HttpRequestMessage Request;
public string ResponseContent = string.Empty;
protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
Request = request;
return await Task.FromResult(new HttpResponseMessage
{
Content = new StringContent(ResponseContent)
});
}
}
Production code:
public async Task<SignupRequestResponse> PostSignupRequest(SignupRequest request)
{
var json = _jsonSerializer.Serialize(request);
await _httpClient.PostAsync(/* url */, new StringContent(json));
return null;
}
I've found a fix now. In my HttpMessageHandler fake I don't just save the Request now, I also explicitly save the content string (which can be extracted at that point since the HttpClient hasn't disposed the request yet). My fake now looks like this:
public class FakeHttpMessageHandler : HttpMessageHandler
{
public HttpRequestMessage Request;
public string LastRequestString = string.Empty;
public string ResponseContent = string.Empty;
protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
CancellationToken cancellationToken)
{
if (request.Content != null) // needed this to prevent some NPEs in other tests, YMMV
{
LastRequestString = await request.Content.ReadAsStringAsync();
}
Request = request;
return await Task.FromResult(new HttpResponseMessage
{
Content = new StringContent(ResponseContent)
});
}
}

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