I want to understand how HandlerMapping work in Annotation based Spring MVC applications. As while working in XML based configuration we have one default and if we want to use other implementation then we have to define it in XML file as well as URL mapping strategies.
To understand HandlerMapping in Annotation based Controller application i came across to
DefaultAnnotationHandlerMapping which used to be default before v3. 1 and now
RequestMappingHandlerMapping is currently used. So I want to understand how to define this HandlerMapping if we are not using XML based configuration and URL mapping strategies. Another thing I came across was HandlerAdapter. So these two things are confusing me.
Please explain step by step when Dispatcher Servlet intercept a request how it find which HandlerMapping to use and how URL mapping strategies work in Annotation based apps.
You can think that HandlerMapping determine a request/URL should be handled by which ways/frameworks (e.g use #Controller to handle ? Use JSP to handle ? etc)
HandlerAdapter drives the actual workflow of handling this request , containing the actual implementation of handling logic.
High Level Logic:
DispatcherServlet intercepts a request
Find out which HandlerMapping can handle this request. Refer to HandlerMapping#getHandler() for the matching logic. It will return a generic object (called a handler object) if the request can be handled.
Find out which HandlerAdapter can handle this handler object (By checking HandlerAdapter#supports()). If a HandlerAdapter can handle , it will handle it (by HandlerAdapter#handle).
experts, I would log every incoming http request call with payload into database.
I checked there would be 2 approaches.
use filter or interceptor.
I feel filter is so easier for me to implement.
what would be best approach for my purpose?
please kindly advise.
thank you very much!
if you have a need to do something completely generic (e.g. log all requests), then a filter is sufficient - but if the behavior depends on the target handler or you want to do something between the request handling and view rendering, then the HandlerInterceptor provides that flexibility.
But anyway, just do the way which make you feel easily and simply.
Note:
Interceptor work in spring application context
Servlet work in web context
Use Spring AOP. Use any advice according to your needs.
#Aspect
#Component
public class Test {
#Around("#annotation(mapping) ")
public Object preAuthUserPersmission(ProceedingJoinPoint joinPoint, RequestMapping mapping) throws Throwable {
Object[] parameters = joinPoint.getArgs();
// Your actions on the input parameters
return joinPoint.proceed(joinPoint.getArgs());
}
}
I wonder what is the full lifecycle of an odata http request over an ODataController hosted in IIS.
For instance:
What are the IIS pipelining steps ?
How is the request handled when entering the ASP.NET controllers area ?
When routing is applied ?
When the Attributes such HttpPost, ApplyFilter are applied ?
Maybe this thread can help you:
The ASP.NET Web API 2 HTTP Message Lifecycle in 43 Easy Steps
It all starts with IIS:
IIS (or OWIN self-hosting) receives a request.
The request is then passed to an instance of HttpServer.
HttpServer is responsible for dispatching HttpRequestMessage objects.
HttpRequestMessage provides strongly-typed access to the request.
If one or more global instances of DelegatingHandler exist on the pipeline, the request is passed to it. The request arrives at the instances of DelegatingHandler in the order said instances were added to the pipeline.
DelegatingHandler instances can skip the remainder of the pipeline and create their own response. I do exactly this in my Custom Validation with FluentValidation post.
If the HttpRequestMessage passes the DelegatingHandler instances (or no such handler exists), then the request proceeds to the HttpRoutingDispatcher instance.
HttpRoutingDispatcher chooses which routing handler to call based on the matching route. If no such route exists (e.g. Route.Handler is null, as seen in the diagram) then the request proceeds directly to Step 10.
If a Route Handler exists for the given route, the HttpRequestMessage is sent to that handler.
It is possible to have instances of DelegatingHandler attached to individual routes. If such handlers exist, the request goes to them (in the order they were added to the pipeline).
An instance of HttpMessageHandler then handles the request. If you provide a custom HttpMessageHandler, said handler can optionally return the request to the "main" path or to a custom end point.
The request is received by an instance of HttpControllerDispatcher, which will route the request to the appropriate route as determined by the request's URL.
The HttpControllerDispatcher selects the appropriate controller to route the request to.
An instance of IHttpControllerSelector selects the appropriate HttpControllerDescriptor for the given HttpMessage.
The IHttpControllerSelector calls an instance of IHttpControllerTypeResolver, which will finally call...
an instance of IAssembliesResolver, which ultimately selects the appropriate controller and returns it to the HttpControllerDispatcher from Step 11.
NOTE: If you implement Dependency Injection, the IAssembliesResolver will be replaced by whatever container you register.
Once the HttpControllerDispatcher has a reference to the appropriate controller, it calls the Create() method on an IHttpControllerActivator...
which creates the actual controller and returns it to the Dispatcher. The dispatcher then sends the request into the Select Controller Action routine, as shown below.
We now have an instance of ApiController which represents the actual controller class the request is routed to. Said instance calls the SelectAction() method on IHttpActionSelector...
Which returns an instance of HttpActionDescriptor representing the action that needs to be called.
Once the pipeline has determined which action to route the request to, it executes any Authentication Filters which are inserted into the pipeline (either globally or local to the invoked action).
These filters allow you to authenticate requests to either individual actions, entire controllers, or globally throughout the application. Any filters which exist are executed in the order they are added to the pipeline (global filters first, then controller-level filters, then action-level filters).
The request then proceeds to the [Authorization Filters] layer, where any Authorization Filters which exist are applied to the request.
Authorization Filters can optionally create their own response and send that back, rather than allowing the request to proceed through the pipeline. These filters are applied in the same manner as Authentication Filters (globally, controller-level, action-level). Note that Authorization Filters can only be used on the Request, not the Response, as it is assumed that if a Response exists, the user had the authorization to generate it.
The request now enters the Model Binding process, which is shown in the next part of the main poster. Each parameter needed by the action can be bound to its value by one of three separate paths. Which path the binding system uses depends on where the value needed exists within the request.
If data needed for an action parameter value exists in the entity body, Web API reads the body of the request; an instance of FormatterParameterBinding will invoke the appropriate formatter classes...
which bind the values to a media type (using MediaTypeFormatter)...
which results in a new complex type.
If data needed for a parameter value exists in the URL or query string, said URL is passed into an instance of IModelBinder, which uses an IValueProvider to map values to a model (see Phil Haack's post about this topic for more info)....
which results in a simple type.
If a custom HttpParameterBinding exists, the system uses that custom binding to build the value...
which results in any kind (simple or complex) of object being mappable (see Mike Stall's wonderful series on this topic).
Now that the request is bound to a model, it is passed through any Action Filters which may exist in the pipeline (either globally or just for the action being invoked).
Once the action filters are passed, the action itself is invoked, and the system waits for a response from it.
If the action produces an exception AND an exception filter exists, the exception filter receives and processes the exception.
If no exception occurred, the action produces an instance of HttpResponseMessage by running the Result Conversion subroutine, shown in the next screenshot.
If the return type is already an HttpResponseMessage, we don't need to do any conversion, so pass the return on through.
If the return type is void, .NET will return an HttpResponseMessage with the status 204 No Content.
If the return type is an IHttpActionResult, call the method ExecuteAsync to create an HttpResponseMessage.
In any Web API method in which you use return Ok(); or return BadRequest(); or something similar, that return statement follows this process, rather than any of the other processes, since the return type of those actions is IHttpActionResult.
For all other types, .NET will create an HttpResponseMessage and place the serialized value of the return in the body of that message.
Once the HttpResponseMessage has been created, return it to the main pipeline.
Pass the newly-created HttpResponseMessage through any AuthenticationFilters which may exist.
The HttpResponseMessage flows through the HttpControllerDispatcher, which at this point probably won't do anything with it.
The Response also flows through the HttpRoutingDispatcher, which again won't do anything with it.
The Response now proceeds through any DelegatingHandlers that are set up to handle it. At this point, the DelegatingHandler objects can really only change the response being sent (e.g. intercept certain responses and change to the appropriate HTTP status).
The final HttpResponseMessage is given to the HttpServer instance.
which returns an Http response to the invoking client
Looking at the source code ,ODataController is another controller which is inherited from
ApiController with custom routing and formatting. So I guess all the logic applied for ApiController
applies to that as well.It also has Custom Formatting and Custom Routing applies using ODataFormatting and ODataRouting
What are the IIS pipelining steps ?
IIS pipelining steps are same like any other mvc controller .In essense,we have all the httpmodules and handlers which forms the pipeline.More details can be found asp.net application lifecycle. From this pieline,when an mvc request comes URLRoutingModule,MvcRouteHandler and Mvchandler works in tandem to serve an MVC request. Explained detailed for the next question.
How is the request handled when entering the ASP.NET controllers area ? When is routing applied ?
Everything starts with an ODataController .Almost everything in MVC is extensible(13 extensibility points in asp.net mvc) you name it and all those points are extended for OData. e.g Starting with Custom Controllers,we have
custom ODataActionSelector which is from IHttpActionSelector .You can find a sample implementation here
IActionValueBinder ,sample implementation here
IContentNegotiator
etc like this many more.
/// Defines a base class for OData controllers that support writing and reading data using the OData formats
/// </summary>
[ODataFormatting]
[ODataRouting]
[ApiExplorerSettings(IgnoreApi = true)]
public abstract class ODataController : ApiController
Receive first request for the application -> In the Global.asax file, Route objects are added to the RouteTable object.
Perform routing -> The UrlRoutingModule module uses the first matching Route object in the RouteTable collection .From ODataRouting, The routes are added to RouteTable collection.
Create MVC request handler -> The MvcRouteHandler object creates an instance of the MvcHandler class and passes the RequestContext instance to the handler
Create controller -> The MvcHandler object uses the RequestContext instance to identify the IControllerFactory object to create the controller instance with
Execute controller -> The MvcHandler instance calls the controller's Execute method
Invoke action -> For controllers that inherit from the ControllerBase class, the ControllerActionInvoker object that is associated with the controller determines which action method of the controller class to call, and then calls that method
7.Action returns all custom CreatedODataResult,UpdatedODataResult etc
There are Custom ODataMediaTypeFormatter registered for ODATA to format the data.
I have a Spring Boot application, that is using Spring Security with OAuth 2.0. Currently, it is operating against an Authentication Server based on Spring Example code. However, running our own Auth Server has always been a short-term target to facilitate development, not a long-term goal. We have been using the authorization_code grant type and would like to continue using that, irrespective of the Auth Server implementation.
I am attempting to make changes to use OAuth 2.0 Endpoints in Azure Active Directory, to behave as our Authentication Server. So far, I have a successful call to the /authorize endpoint. But the call to get the /token fails with an invalid request error. I can see the requests going out.
It appears that parameters that Azure states as mandatory are not being populated in the POST request. Looking at the Azure doco, it expects the client_id to be defined in the body of the message posted to the endpoint, and that is not added, by default, by Spring.
Can anyone point me in the right direction for how I can add fields to the Form Map that is used when constructing the Access Token request? I can see where the AccessTokenRequest object is being setup in OAuth2ClientConfiguration....
#Bean
#Scope(value = "request", proxyMode = ScopedProxyMode.INTERFACES)
protected AccessTokenRequest accessTokenRequest(#Value("#{request.parameterMap}")
Map<String, String[]> parameters, #Value("#{request.getAttribute('currentUri')}")
String currentUri) {
DefaultAccessTokenRequest request = new DefaultAccessTokenRequest(parameters);
request.setCurrentUri(currentUri);
return request;
}
Should I be trying to define the map in a request.parameterMap spring property? If so, I'm not too sure how that works.
Or should I be using one of the interfaces defined in the AuthorizationServerConfigurerAdapter class?
I have the information to include when sending the AccessTokenRequest, I just don't know the best way to configure Spring to include it? Thanks for any help.
Actually, I found this out. I needed to change the client authentication scheme. Simply adding the following to my application properties added the client_id to the form....
security.oauth2.client.clientAuthenticationScheme=form
If you're using yaml, then yaml-ize it. Thank you Spring!
I'm not sure if this is possible, or if there's a simpler way of achieving my needs...
I have a login form that used to post back to our legacy system.
I have used jQuery to intercept this and post the form data back into the partially migrated system running on ASP.Net MVC - I now need to forward this call back to the legacy system with the original form data.
I have tried the following:
[AcceptVerbs(HttpVerbs.Post)]
public void V6Login(FormCollection formData)
{
Server.Transfer("/bin/ussI.dll/do?cmd=Login", true);
}
but I get the following error:
No http handler was found for request type 'POST'
You need to ensure that you have an HTTP handler for the ussI.dll defined in your config for ASP.NET to know about it.