I am looking for a solution related to passing cookies values from JAX-RX REST API endpoint to ejb layer.
I tried searching the solution and found some of them are using thread local. but and thread local supposed to be not working with executor services.
Is there any another solution that I can use to pass cookies values from web/rest later to ejb layer.
Note: I do not want to pass it as method parameter from rest layer to down the ejb layer. I would like to access the cookies values directly in ejb layer
Thanks
Lets say you have a class MyEJB, you can inject HttpServletRequest object to you ejb as follows:
public class MyEJB{
#Context
private HttpServletRequest httpRequest;
}
Now from this request object you can access your required cookies. As follows:
String rawCookie = request.getHeader("Cookie");
String[] rawCookieParams = rawCookie.split(";");
for(String rawCookieNameAndValue :rawCookieParams)
{
String[] rawCookieNameAndValuePair = rawCookieNameAndValue.split("=");
}
Can I autowire HttpServletRequest in my RestController like following and will it returns different servletRequest even if it is executed in highly concurrent environment. I have a restriction that I can not have as method parameter because I am implementing an interface which is auto generated and will not have HttpServletRequest as the method parameter.
#RestController
public class MyController implements MyInterface {
#Autowired
private HttpServletRequest servletRequest;
#Override
#RequestMapping(value = "/test", produces = {"application/json"}, consumes = {"application/json"}, method = RequestMethod.POST)
public ResponseEntity<MyResponse> test(#RequestBody final MyRequest payload){
...
}
...
}
I have gone through these SO questions and some other articles on this. But just wanted to ensure that when we autowire HttpServletRequest in the controller then its Scope is Request?
Spring 3 MVC accessing HttpRequest from controller
How are Threads allocated to handle Servlet request?
Scope of a Spring-Controller and its instance-variables
How do I get a HttpServletRequest in my spring beans?
How To Get HTTP Request Header In Java
Note: I did try this and it seems to work fine. But just wanted to confirm that it's a foolproof solution even in a highly concurrent environment.
Also if this is the correct way to do it, I would appreciate if someone can explain how exactly it works.
I have used this and it works fine. But unfortunately I did not find any official documentation which mentions that this should work.
Here is the explanation based on my understanding from debugging the code with running multiple requests with different headers/payload etc.:
Whether we autowire on field or through the constructor, servletRequest acts like a Proxy object which delegates the call to Current HttpServletRequest which is different for each request. Thus, even though it's injected through constructor in a Singleton RestController, it will still have the call delegated to corresponding HttpServletRequest for each new request. This utilizes AutowireUtils.ObjectFactoryDelegatingInvocationHandler to access the current HttpServletRequest object. The java doc for it also says Reflective InvocationHandler for lazy access to the current target object.
Thus even if the autowired Proxy object is always the same for all requests, the underlying target object to which the call is delegated is the current HttpServletRequest object which is per-request.
There is another way you can get HttpServletRequest is using RequestContextHolder as mentioned in this answer
HttpServletRequest currentRequest =
((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes())
.getRequest();
Note: As this explanation is based on my understanding, please do share any official documentation about this if anyone has it.
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.
So I have a Jersey REST service and I need to get access to a ServletConfig so that I can pull a param out of the web.xml. I can use #Context to wire one in but I don't think it will get me the params I need. Only the ones in the ServletContext.
Any ideas? I'm new to Jersey and this Provider isn't a Servelet. Perhaps I should start with trying to retrieve the servelet?
#Context: annotation can be used to inject the following classes
HttpServletRequest
HttpServletResponse
ServletContext
ServletConfig
WebConfig.
onto a root resource, provider and Application classes.
Java Doc of Servlet Container
This feels like a basic question, but I haven't had much luck Googling.
My app connects to an SMTP server and sends mail through it. I need this SMTP server to be configurable based on which environment the app is deployed to.
How can I specify the specify the SMTP server name in my web.xml config file and access it from my Spring MVC 3.0 controller?
The controller does not extend or implement anything. It is completely annotation driven with #Controller and #RequestMapping. From what I have seen online, people access context-params via the servlet API. Being annotation driven, I do not have access to the servlet object.
I solved this.
Make your controller implement ServletContextAware, which requires a method called
setServletContext(ServletContext servletContext)
Spring MVC will inject the servlet context into this method if your controller is ServletContextAware.
Create a private variable on your controller to store the servletController that is injected into the above method. You can now use servletContext just as you would if you were using a regular servlet.
hth.
Adding an instance of Servletcontext and autowiring it worked for me
#Controller
public MyController {
// other instances relevant to your requirement
#Autowired
private ServletContext sCtx;
//other methods relevant to your requirement
}
I suppose following also should work:
void action(final HttpServletRequest request) {
final paramValue = request.getSession().getServletContext().getInitParameter("paramName");
...
}