I am using ServiceStack (the ServiceStack client is 4.0.12.0).
I have some code as below:
private async Task TestSave()
{
JsonServiceClient client = new JsonServiceClient("http://localhost:60982");
try
{
this.Items = client.Post(new ItemDescUpdateRequest() { Items = this.Items });
}
catch (WebServiceException ex)
{
HandleWebException(ex);
}
}
If I use Post and the server throws an exception. The server exception comes back correctly. I can use ex.ErrorMessage to see the message. However, If I change to:
this.Items = await client.PostAsync(new ItemDescUpdateRequest() { Items = this.Items
the exception does not get handled correctly.
The ResponseBody has data in it as does the ResponseDTO. However ResponseStatus is null. ErrorCode and ErrorMessage get a System.IndexOutOfRangeException error, I am assuming because ResponseStatus is null.
Why doesn't PostAsync work as expected?
Related
I have a control that calls a service.
If the service returns an empty payload from the db I want to throw an exception.
at the moment I am doing that in the service:
this is the service I have at the moment with the exception.
async getPreferences(eUserId: string): Promise<UserPreferences> {
const userPreferences = await this.userPreferencesModel.findOne({
eUserId,
});
if (!userPreferences) {
throw new NotFoundException("We couldn't find your user preferences");
}
return userPreferences;
}
I want the controller to handle the exception, The issue is that the controller response is a Promise.
How can I handle that?
This is what I shave done:
#Get()
async getPreferences(
#Headers('x-e-user-id') eUserId: string,
): Promise<UserPreferences> {
const userPreferences = this.userPreferencesService.getPreferences(eUserId);
console.log('userPreferences: ', userPreferences);
// Here is what I am trying to monitor...
if (userPreferences) {
throw new NotFoundException("We couldn't find your user preferences");
}
return userPreferences;
}
Ther console.log in the controller returns:
userPreferences: Promise { <pending> }
Now, if the service response is empty no exception is thrown.
How can I monitor the service result in order to throw an exception
Multiple ways you can solve this. Here's one.
Don't throw an error in your service, just return the result or null.
async getPreferences(eUserId: string): Promise<UserPreferences | null> {
return this.userPreferencesModel.findOne({
eUserId,
});
}
Then in your controller await for the result, you forgot this. That's why you are seeing a pending promise. After the result has been resolved, check if any user preferences were returned and throw the NotFoundException if not.
#Get()
async getPreferences(#Headers('x-e-user-id') eUserId: string): Promise<UserPreferences> {
const userPreferences = await this.userPreferencesService.getPreferences(eUserId);
if (!userPreferences) {
throw new NotFoundException("We couldn't find your user preferences");
}
return userPreferences;
}
I would not throw NotFoundException or any other HTTP related error from your service. Leave that responsibility up to your controller, don't tie your service (logic) to HTTP error codes. Throw errors here that are not aware of the context (HTTP) they are being used in.
PS: You might also consider passing the user ID via the query string or as a route parameter instead of via the headers.
I'm learning Blazor.
I have created a Blazor WASM App with the "ASP.NET Core Hosted" option.
So I have 3 projects in the solution: Client, Server and Shared.
The following code is in the Client project and works perfectly when the endpoint is correct (obviously). But at some point I made a mistake and messed up the request URI, and then I noticed that the API returned an HTML page with code 200 OK (as you can see in the Postman screenshot below the code).
I expected one of my try-catches to get this, but the debugger jumps to the last line (return null) without throwing an exception.
My first question is why?
My second question is how can I catch this?
I know fixing the endpoint fixes everything, but would be nice to have a catch that alerts me when I have mistyped an URI.
Thanks.
private readonly HttpClient _httpClient;
public async Task<List<Collaborator>> GetCollaborators()
{
string requestUri = "api/non-existent-endpoint";
try
{
var response = await _httpClient.GetFromJsonAsync<CollaboratorsResponse>(requestUri);
if (response == null)
{
// It never enters here. Jumps to the last line of code.
}
return response.Collaborators;
}
catch (HttpRequestException)
{
Console.WriteLine("An error occurred.");
}
catch (NotSupportedException)
{
Console.WriteLine("The content type is not supported.");
}
catch (JsonException)
{
Console.WriteLine("Invalid JSON.");
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
return null;
}
it is a never good idea to use GetFromJsonAsync, You are not the first who are asking about the strange behavior. Try to use GetAsync. at least you will now what is going on.
var response = await client.GetAsync(requestUri);
if (response.IsSuccessStatusCode)
{
var stringData = await response.Content.ReadAsStringAsync();
var result = JsonConvert.DeserializeObject<CollaboratorsResponse>(stringData);
... your code
}
else
{
var statusCode = response.StatusCode.ToString(); // HERE is your error status code, when you have an error
}
I have an application with both MVC and 'new' ApiController endpoints in ASP.NET Core 2.2 co-existing together.
Prior to adding the API endpoints, I have been using a global exception handler registered as middleware using app.UseExceptionHandler((x) => { ... } which would redirect to an error page.
Of course, that does not work for an API response and I would like to return an ObjectResult (negotiated) 500 result with a ProblemDetails formatted result.
The problem is, I'm not sure how to reliably determine in my 'UseExceptionHandler' lambda if I am dealing with an MVC or a API request. I could use some kind of request URL matching (eg. /api/... prefix) but I would like a more robust solution that won't come back to bite me in the future.
Rough psuedo-code version of what I'm trying to implement is:
app.UseExceptionHandler(x =>
{
x.Run(async context =>
{
// extract the exception that was thrown
var ex = context.Features.Get<IExceptionHandlerFeature>()?.Error;
try
{
// generically handle the exception regardless of what our response needs to look like by logging it
// NOTE: ExceptionHandlerMiddleware itself will log the exception
// TODO: need to find a way to see if we have run with negotiation turned on (in which case we are API not MVC!! see below extensions for clues?)
// TODO: ... could just use "/api/" prefix but that seems rubbish
if (true)
{
// return a 500 with object (in RFC 7807 form) negotiated to the right content type (eg. json)
}
else
{
// otherwise, we handle the response as a 500 error page redirect
}
}
catch (Exception exofex)
{
// NOTE: absolutely terrible if we get into here
log.Fatal($"Unhandled exception in global error handler!", exofex);
log.Fatal($"Handling exception: ", ex);
}
});
});
}
Any ideas?
Cheers!
This might be a bit different than what you expect, but you could just check if the request is an AJAX request.
You can use this extension:
public static class HttpRequestExtensions
{
public static bool IsAjaxRequest(this HttpRequest request)
{
if (request == null)
throw new ArgumentNullException(nameof(request));
if (request.Headers == null)
return false;
return request.Headers["X-Requested-With"] == "XMLHttpRequest";
}
}
And then middleware with an invoke method that looks like:
public async Task Invoke(HttpContext context)
{
if (context.Request.IsAjaxRequest())
{
try
{
await _next(context);
}
catch (Exception ex)
{
//Handle the exception
await HandleExceptionAsync(context, ex);
}
}
else
{
await _next(context);
}
}
private static Task HandleExceptionAsync(HttpContext context, Exception exception)
{
//you can do more complex logic here, but a basic example would be:
var result = JsonConvert.SerializeObject(new { error = "An unexpected error occurred." });
context.Response.ContentType = "application/json";
context.Response.StatusCode = 500;
return context.Response.WriteAsync(result);
}
see this SO answer for a more detailed version.
If you want to check whether the request is routed to ApiController, you could try IExceptionFilter to hanlde the exceptions.
public class CustomExceptionFilter : IExceptionFilter
{
public void OnException(ExceptionContext context)
{
if (IsApi(context))
{
HttpStatusCode status = HttpStatusCode.InternalServerError;
var message = context.Result;
//You can enable logging error
context.ExceptionHandled = true;
HttpResponse response = context.HttpContext.Response;
response.StatusCode = (int)status;
response.ContentType = "application/json";
context.Result = new ObjectResult(new { ErrorMsg = message });
}
else
{
}
}
private bool IsApi(ExceptionContext context)
{
var controllerActionDesc = context.ActionDescriptor as ControllerActionDescriptor;
var attribute = controllerActionDesc
.ControllerTypeInfo
.CustomAttributes
.FirstOrDefault(c => c.AttributeType == typeof(ApiControllerAttribute));
return attribute == null ? false : true;
}
}
Thanks to all of the advice from others, but I have realised after some more thought and ideas from here that my approach wasn't right in the first place - and that I should be handling most exceptions locally in the controller and responding from there.
I have basically kept my error handling middleware the same as if it was handling MVC unhandled exceptions. The client will get a 500 with a HTML response, but at that point there isn't much the client can do anyway so no harm.
Thanks for your help!
I try to use swagger ui for rest api documentation. Rest API created with WCF service. I solved cors issue, service accepts OPTIONS method. But request has a header parameter which name is SessionUUID, this parameter doesn't send to service. When i debug the service side, this parameter does not come. This problem is only in Chrome. Chrome blocks to header params in cors request.
Cors problem's solving on WCF Service like this;
I added new behavior and header params are defined
public class EnableCorsEndpointBehavior : BehaviorExtensionElement, IEndpointBehavior
{
...
public void ApplyDispatchBehavior(ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.EndpointDispatcher endpointDispatcher)
{
var requiredHeaders = new Dictionary<string, string>();
requiredHeaders.Add("Access-Control-Allow-Origin", "*");
requiredHeaders.Add("Access-Control-Request-Method", "POST,GET,PUT,DELETE,OPTIONS");
requiredHeaders.Add("Access-Control-Allow-Headers", "X-Requested-With, Content-Type, Accept, Accept-Language, SessionUUID, Origin, X-Custom-Header, sessionuuid");
requiredHeaders.Add("Access-Control-Allow-Credentials", "true");
endpointDispatcher.DispatchRuntime.MessageInspectors.Add(new ServiceInspector(requiredHeaders));
}
...
}
I added response headers in inspector. Header parameter which named as SessionUUID is checked in AfterReceiveRequest but it is null, because of this problem.
public object AfterReceiveRequest(ref System.ServiceModel.Channels.Message request, System.ServiceModel.IClientChannel channel, System.ServiceModel.InstanceContext instanceContext)
{
try
{
WebHeaderCollection headers = WebOperationContext.Current.IncomingRequest.Headers;
string requestTo = request.Headers.To.ToString();
if (!requestTo.Contains("login") && request.GetType().Name != "InternalByteStreamMessage")
{
if (headers["SessionUUID"] == null)
{
throw new RestAppException("401", "Oturum bilgisi bulunamadı.");
}
else
{
DateTime requestDate = DateTime.Now;
string sessionUUID = headers["SessionUUID"] != null ? headers["SessionUUID"].AsString() : headers["sessionuuid"].AsString();
sessionManager.CheckSessionByUUID(sessionUUID, requestDate);
sessionManager.UpdateExpireDate(sessionUUID, requestDate);
sessionManager.SetSessionByUUID(sessionUUID);
}
}
}
catch (RestAppException ex)
{
ex.Message = "İşlem Başarısız";
throw ex;
}
catch (Exception ex)
{
throw ex;
}
return null;
}
public void BeforeSendReply(ref System.ServiceModel.Channels.Message reply, object correlationState)
{
var httpHeader = reply.Properties["httpResponse"] as HttpResponseMessageProperty;
foreach (var item in requiredHeaders)
{
httpHeader.Headers.Add(item.Key, item.Value);
}
}
How can i solve this chrome issue?
You will have to add a Chrome extension to allow custom headers.
Here are some that you could use:
WebRequestAPI
Mod Header
In case you want to try out Mozilla Firefox, use its extension modify-headers.
I had a similar problem . It may be related to the url.
My problem was solved when I entered with "www".
If already you entered with "www", delete this and try again.
I'm trying to send an object type UserEntry to the client.
the route I used was: http://localhost:3027/api/userapi/getinfo?username=myUsername
What is the cause of this error or what is wrong with my code?
[HttpGet, Route("api/userapi/getinfo")]
public async Task<string> getUserInfo([FromUri]string username)
{
UserEntry u = await UserEntry.getUserInfo(username);
return new JavaScriptSerializer().Serialize(u);
}
Here is what inner exception shows:
InnerException: {
Message: "An error has occurred.",
ExceptionMessage: "Invalid operation. The connection is closed.",
ExceptionType: "System.InvalidOperationException",
StackTrace: " at System.Data.SqlClient.SqlConnection.GetOpenConnection() at System.Data.SqlClient.SqlConnection.get_ServerVersion()"
}
I checked and made sure that there was no error in connecting with the database, but it still shows error.
I temporarily solved it by making it synchronous
I solved it by making it synchronous
[HttpGet,Route("api/userapi/getinfo")]
public SimpleUser getUserInfo([FromUri]string username)
{
var ur = new UserRepository();
return ur.getUser(username).First();
}
public IEnumerable<SimpleUser> getUser(string username)
{
UserEntryDBContext context = new UserEntryDBContext();
UserEntry u = context.Users.Where( x => x.username == username).FirstOrDefault();
List<SimpleUser> s = new List<SimpleUser>();
s.Add(new SimpleUser(u));
return s;
}
but I still have no idea what causes the error nor how can I make it asynchronous.