I am using Golang to write web applications, and I use beego framework. It seems the the framework have the internal status code returned for golang web server.
I am wondering is there any method in golang or beego, or other tools that can let me control the status code returned to browser, say 200, or 500 or others number.
In your controller you can access the http.ResponseWriter via the Ctx
type SomeController struct {
beego.Controller
}
func (c *SomeController) Get() {
c.Ctx.ResponseWriter.WriteHeader(500)
}
Edit: After further inspection you should probably do this:
func (c *SomeController) Get() {
c.CustomAbort(500, "Internal server error")
}
I'm leaving the reference about the context because you can find the http.Request and http.ResponseWriter on controller's Ctx property.
Have a look on http.ResponseWriter.WriteHeader. If you have access to the ResponseWriter-object, you can easily return your own HTTP status code.
c.Abort("500")
it response HTTP code is 200.
Must be:
c.Ctx.ResponseWriter.WriteHeader(500)
Very late to the party. I m able to set status on beego v2.0.2.
func (u *UserController) Post() {
var user models.User
json.Unmarshal(u.Ctx.Input.RequestBody, &user)
uid, _ := models.AddUser(&user)
u.Data["json"] = map[string]interface{}{"uid": uid}
u.Ctx.Output.Status = http.StatusCreated #<<<------------
u.ServeJSON()
}
Related
Let's say I have multiple services. One service is calling another service to get something. That service also gets some information from a third party vendor. Let's say the third party vendor returned a Too Many Requests message with 429 status code. The method that calls the third party vendor is used by lots of other methods and can be called directly via GET Request or within another Http Request.
When I detect the 429 status code, I was throwing a custom exception (let's say TooManyRequestsException) and using the Mapper to send the code to the requester.
Config.MapExceptionToStatusCode.Add(typeof(TooManyRequestsException),429);
It works if the method is called directly. But obviously I forgot the fact that this method was called by many other methods inside the service and all other methods are wrapping this exception with generic System.Exception objects with custom messages inside their catch blocks.
What other options do I have other than changing all the methods that wrap the exception with System.Exception? I tried to go over http://docs.servicestack.net/error-handling but couldn't really find a way that would help me, or couldn't make sense of it.
I recommend looking at Overriding OnExceptionTypeFilter in your AppHost which will let you apply custom logic to inspect the Exception and customize the ResponseStatus returned:
public override void OnExceptionTypeFilter(
Exception ex, ResponseStatus responseStatus)
{
var argEx = ex as ArgumentException;
var isValidationSummaryEx = argEx is ValidationException;
if (argEx != null && !isValidationSummaryEx && argEx.ParamName != null)
{
var paramMsgIndex = argEx.Message.LastIndexOf("Parameter name:");
var errorMsg = paramMsgIndex > 0
? argEx.Message.Substring(0, paramMsgIndex)
: argEx.Message;
responseStatus.Errors.Add(new ResponseError
{
ErrorCode = ex.GetType().Name,
FieldName = argEx.ParamName,
Message = errorMsg,
});
}
}
experts
I'm running into a trouble when access the home page in my MVC 5 web site, please see the exception details below.
MVC 5.2.2
EntityFramework 6.1.1
Visual Studio 2013
System.NullReferenceException: Object reference not set to an instance of an object.
at System.Data.Entity.Core.Objects.ELinq.QueryParameterExpression.TryGetFieldOrPropertyValue(MemberExpression me, Object instance, Object& memberValue)
at System.Data.Entity.Core.Objects.ELinq.QueryParameterExpression.TryEvaluatePath(Expression expression, ConstantExpression& constantExpression)
at System.Data.Entity.Core.Objects.ELinq.QueryParameterExpression.EvaluateParameter(Object[] arguments)
at System.Data.Entity.Core.Objects.ELinq.ELinqQueryState.GetExecutionPlan(Nullable`1 forMergeOption)
at System.Data.Entity.Core.Objects.ObjectQuery`1.<>c__DisplayClassc.<GetResultsAsync>b__a()
at System.Data.Entity.Core.Objects.ObjectContext.<ExecuteInTransactionAsync>d__3d`1.MoveNext()
The code is quite simple, it query data asynchronously from the data context shared in the current OwinContext, it works well as usual, but accidentally, it fail because of the error previously.
public class TalentsService : ServiceBase
{
public async Task<List<TalentSummaryViewModel>> GetSlotlightTalents()
{
var talents = await DbContext.Talents.Where(t => t.IsSpotlight && IsAuthenticated).ToListAsync();
return talents.Select(t => WrapModel(t)).ToList();
}
}
public abstract class ServiceBase
{
private ApplicationDbContext _dbContext;
public ApplicationDbContext DbContext
{
get
{
return _dbContext ?? HttpContext.Current.GetOwinContext().Get<ApplicationDbContext>();
}
private set
{
_dbContext = value;
}
}
public bool IsAuthenticated
{
get
{
return HttpContext.Current.Request.IsAuthenticated;
}
}
}
Is that multi-thread related? I can't figure out what could be the root cause, any clue would be appreciated, thanks in advance.
Thanks Chris Pratt for the response which led me to double check my code, the root cause is that:
The HttpContext.Current is null in some scenario which I'm not aware of, then the call to this property IsAuthenticated failed, so I would have to store the IsAuthenticated value in a local variable, now I could repro this issue easily when use the LoadTest tool to launch lots of request, but still not clear why does the context get lost accidentally, probably somebody else have more knowledge on this.
I had the same error after the 1st HTTP request to my Web API which was reproducible only if the IIS application was recycled. Apparently after restarting IIS the first incoming request was initiating data retrieval via IQueryable with inline ClientID parameter extracted from:
(HttpContext.Current.User as ClaimsPrincipal).Claims collection in asynchronous fashion.
So by the time the I/O operation was completed -- the HttpRequest context did not exist...
Copying Http Claim value into separate variable and using this variable when contructing IQueryable solved the problem:
var claims = (HttpContext.Current.User as ClaimsPrincipal).Claims;
I have set expectedResponseType(MyClass.class). So OutboundGateway is converting the message into my response class type and returning to me. I want to log the payload as well for debugging purpose along with the conversion.
How to do this response payload logging and conversion.?
I could do it by expecting the response as String and later convert into my class using marshallers. Is there any simpler way that can be used for all my outbound gateways?
The expectedResponseType(MyClass.class) is translated to the
httpResponse = this.restTemplate.exchange(realUri, httpMethod, httpRequest, (Class<?>) expectedResponseType);
where the last one does this:
public ResponseEntityResponseExtractor(Type responseType) {
if (responseType != null && Void.class != responseType) {
this.delegate = new HttpMessageConverterExtractor<T>(responseType,
getMessageConverters(), logger);
}
else {
this.delegate = null;
}
}
As you see it is copying its own logger to the HttpMessageConverterExtractor.
So, I think you can achieve some good result for your logging requirements switching on DEBUG (or even TRACE) for the org.springframework.web.client.RestTemplate category.
From other side you always can extend the RestTemplate a bit to make some hooks into it.
From the Spring Integration perspective we can do nothing. Because the whole hard conversion work is done in the RestTemplate.
My problem is...
...I have a DTO like this
[Route("/route/to/dto/{Id}", "GET")]
public class Foo : IReturn<Bar>
{
public string Id { get; set; }
}
and need to call the service that implements the method with this signature
public Bar Get(Foo)
from a request and/or response filter. I don't know what class implements it (don't want to need to know). What I need is something like the LocalServiceClient class in the example below:
var client = new LocalServiceClient();
Bar bar = client.Get(new Foo());
Does this LocalServiceClient thing exists? JsonServiceClient has a pretty similar interface, but using it would be inneficient (I need to call my own service, I shouldn't need an extra round-trip, even to localhost, just to do this).
I'm aware of ResolveService method from Service class, but it requires me to have a service instance and to know what class will handle the request.
I think this LocalServiceClient is possible because I have all the data that a remote client (e.g. JsonServiceClient) needs to call the service - request DTO, route, verb - but couldn't find how to do it. Actually, it should be easier to implement than JsonServiceClient.
JsonServiceClient would do it, but there must be a better way, using the same request context.
What I want to do (skip this if you're not curious about why I'm doing this)
Actually, my DTOs are like this:
[EmbedRequestedLinks]
[Route("/route/to/dto/{Id}", "GET")]
public class MyResponseDto
{
public string Id { get; set; }
public EmbeddableLink<AResponseDto> RelatedResource { get; set; }
public EmbeddableLink<AnotherResponteDto> AnotherRelatedResource { get; set; }
}
EmbedRequestedLinksAttribute is a request/response filter. This filter checks if there is a query argument named "embed" in the request. If so, the filter need to "embed" the comma-separated related resources referenced by the argument into the response to this request. EmbeddableLink<T> instances can be obtained by using extension methods like these:
1) public static EmbeddableLink<T> ToEmbeddableLink<T>(this IReturn<T> requestDto)
2) public static EmbeddableLink<T> ToEmbeddableLink<T>(this T resource)
Assume a client places this request:
GET /route/to/dto/123456?embed=relatedResource HTTP/1.1
The service that will handle this request will return an instance of MyResponseDto with EmbeddableLinks created using signature (1). Then my response filter will see the embed query argument and will call the Get method of the appropriate service, replacing the RelatedResource with another instance of EmbeddableLink, this time created using extension method (2):
var client = new LocalServiceClient();
response.RelatedResource = client.Get(response.RelatedResource.RequestDto)
.ToEmbeddableLink();
The serialization routine of EmbeddableLink takes care of the rest.
In case an embeddable link is not included in the embed list the serialization routine will call the extension method ToUrl (provided by ServiceStack), that takes a verb and converts a request DTO into a URL. In this example the client will get this response:
{
"id": "9asc09dcd80a98",
"relatedResource": { "id": "ioijo0909801", ... },
"anotherRelatedResource":
{
"$link": { "href": "/route/to/another/dto/1sdf89879s" }
}
}
I know the creators of ServiceStack think that polymorphic request/responses are bad things but this case seems OK to me because I'm not creating services, instead I'm extending the framework to help me create services the way I (and possibly other users of ServiceStack) need. I'm also creating other hypermedia extensions to ServiceStack. (I hope my boss allow me to publish these extensions on github)
If you really want to do this then look the source code for ServiceStack. Look at the ServiceManager and ServiceController. These classes are responsible for registering and resolving services. You might even be able to use reflection to create services on the fly with the static EndpointHost.Metadata like so:
var operation = EndpointHost.Metadata.Operations
.FirstOrDefault(x => x.RequestType == typeof(Person));
if (operation != null)
{
var svc = Activator.CreateInstance(operation.ServiceType);
var method = operation.ServiceType.GetMethod("Get");
var response = method.Invoke(svc, new[] { new Person() });
}
This kinda works but you will get NULL exceptions if there is other code calling
var httpRequest = RequestContext.Get<IHttpRequest>();
But I would not suggest this.
Instead if you create your own Business Service classes that do all the CRUD operations (POST/PUT/GET ect). Then make the ServiceStack Services thin wrappers over them. Now you can call your own services whenever you want without worrying about the HTTP Request and ServiceStack. Only use the ServiceStack Service when you are dealing with HTTP requests
You can call the static AppHostBase.Resolve() method as demonstrated here, calling a SeviceStack Service from an MVC controller:
var helloService = AppHostBase.Resolve<HelloService>();
helloService.RequestContext = System.Web.HttpContext.Current.ToRequestContext();
var response = (HelloResponse)helloService.Any(new HelloRequest { Name = User.Identity.Name });
However, I would take #kampsj's approach of making your ServiceStack services a thin wrapper around your application service classes and only deal with HTTP/Session specific stuff in the ServiceStack service.
How can I get GWT RequestFactory to with in a Gadget?
Getting GWT-RPC to work with Gadgets is explained here.
I'm looking for a analogous solution for RequestFactory.
I tried using the GadgetsRequestBuilder, so far I've managed to get the request to the server using:
requestFactory.initialize(eventBus, new DefaultRequestTransport() {
#Override
protected RequestBuilder createRequestBuilder() {
return new GadgetsRequestBuilder(RequestBuilder.POST,
getRequestUrl());
}
#Override
public String getRequestUrl() {
return "http://....com/gadgetRequest";
}
});
But I end up with the following error:
java.lang.StringIndexOutOfBoundsException: String index out of range: 0
at java.lang.String.charAt(String.java:694)
at com.google.gwt.autobean.server.impl.JsonSplittable.create(JsonSplittable.java:35)
at com.google.gwt.autobean.shared.impl.StringQuoter.split(StringQuoter.java:35)
at com.google.gwt.autobean.shared.AutoBeanCodex.decode(AutoBeanCodex.java:520)
at com.google.gwt.requestfactory.server.SimpleRequestProcessor.process(SimpleRequestProcessor.java:121)
The general approach for sending a RequestFactory payload should be the same as RPC. You can see the payload that's being received by the server by running it with the JVM flag -Dgwt.rpc.dumpPayload=true. My guess here is that the server is receiving a request with a zero-length payload. What happens if you set up a simple test involving a GadgetsRequestBuilder sending a POST request to your server? Do you still get the same zero-length payload behavior?