Limit connection in RESTful web service - jax-rs

Is there a way to configure a rest web service to allow only one connection at a time?
I am using Wildfly 9.0.1-Final with the resteasy 3.0.11.Final implementation.

You can use synchronized block on static field:
private static final Object LOCK = new Object();
#GET
#Path("find")
#Produces(MediaType.APPLICATION_JSON)
public Response find(){
synchronized(LOCK){
//your code
}
}

Related

Is there a way to ensure the HTTP request body can be loaded into memory for possible multiple read requests?

Is there a way to ensure the HTTP request body can be loaded into memory? There are multiple middle-wares which will use same HTTP Request body to log at multiple levels.
I remember doing following in .Net Framework 4.6
await request.Content.LoadIntoBufferAsync();
/// *** Method snapshot from HttpContent - System.Net.Http library ***
/// <summary>Serialize the HTTP content to a memory buffer as an asynchronous operation.</summary>
/// <returns>The task object representing the asynchronous operation.</returns>
public Task LoadIntoBufferAsync()
{
return this.LoadIntoBufferAsync((long) int.MaxValue);
}
Can anyone help me find similar behavior in .Net Core?
EDIT
-- I think right answer here is to use EnableBuffering, but I am not to able to figure out which overloaded method should I use for EnableBuffering?
public static void EnableBuffering(this HttpRequest request)
{
BufferingHelper.EnableRewind(request);
}
public static void EnableBuffering(this HttpRequest request, int bufferThreshold)
{
BufferingHelper.EnableRewind(request, bufferThreshold);
}
public static void EnableBuffering(this HttpRequest request, long bufferLimit)
{
BufferingHelper.EnableRewind(request, bufferLimit: bufferLimit);
}
Size of HTTP Request in our application is varying from 50kb to 300mb.
For asp.net core 2.x you can use :
HttpContext.Request.EnableRewind();
For asp.net core 3.x you can use :
HttpContext.Request.EnableBuffering();
That methods ensure the request Body can be read multiple times. Normally buffers request bodies in memory :
https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.http.httprequestrewindextensions.enablebuffering?view=aspnetcore-3.1

How to configure hangfire with unity?

I have ASP.NET Web API application. The application is using Unity as IoC container. The application is also using Hangfire and I am trying to configure Hangfire to use Unity.
So based on documentation i am using Hangfire.Unity which registers the unity container as a current job activator in Hangfire.
I have a class which has dependency on IBackgroundJobClient
public class MyService
{
private MyDBContext _dbContext = null;
private IBackgroundJobClient _backgroundJobClient = null;
public MyService(MyDbContext dbContext, IBackgroundJobClient backgroundJobClient)
{
_dbContext = dbContext;
_backgroundJobClient = backgroundJobClient;
}
}
However even after configuring Hangfire.Unity it could not create & pass instance of BackgroundJobClient
So i had to register every dependency of BackgroundJobClient with unity container.
Unity Registration
public class UnityConfig
{
private static Lazy<IUnityContainer> container = new Lazy<IUnityContainer>(() =>
{
var container = new UnityContainer();
RegisterTypes(container);
return container;
});
public static IUnityContainer GetConfiguredContainer()
{
return container.Value;
}
public static void RegisterTypes(IUnityContainer container)
{
container.RegisterType<MyDbContext>(new HierarchicalLifetimeManager(), new InjectionFactory(x => new MyDbContext()));
// register hangfire dependencies
container.RegisterType<IBackgroundJobClient, BackgroundJobClient>();
container.RegisterType<JobStorage, SqlServerStorage>(new InjectionConstructor("HangfireConnectionString"));
container.RegisterType<IJobFilterProvider, JobFilterAttributeFilterProvider>(new InjectionConstructor(true));
container.RegisterType<IBackgroundJobFactory, BackgroundJobFactory>();
container.RegisterType<IRecurringJobManager, RecurringJobManager>();
container.RegisterType<IBackgroundJobStateChanger, BackgroundJobStateChanger>();
}
}
OWIN Startup
public class Startup
{
public void Configuration(IAppBuilder app)
{
var container = UnityConfig.GetConfiguredContainer();
Hangfire.GlobalConfiguration.Configuration.UseSqlServerStorage("HangfireConnectionString");
Hangfire.GlobalConfiguration.Configuration.UseUnityActivator(container);
// if i dont call UseSqlServerStorage() above then UseHangfireDashboard() method fails with exception
//JobStorage.Current property value has not been initialized. You must set it before using Hangfire Client or Server API.
app.UseHangfireDashboard();
app.UseHangfireServer();
RecurringJob.AddOrUpdate<MyService>(x => x.Prepare(), Cron.MinuteInterval(10));
}
}
Code is working with such configuration. However i have questions:
Is this the correct way of configuring Unity with Hangfire?
Why do i need to invoke Hangfire.GlobalConfiguration.Configuration.UseSqlServerStorage("HangfireConnectionString") in OWIN startup even though SqlServerStorage is already registered with Unity container as JobStorage?
If i dont invoke UseSqlServerStorage() method in OWIN startup then i get exception on app.UseHangfireDashboard() method.
JobStorage.Current property value has not been initialized. You must
set it before using Hangfire Client or Server API.
I believe there is a problem where you want to kick off Hangfire outside of the Unity ecosystem, but also want Unity to understand how to instantiate the appropriate Hangfire interfaces with the associated implementations. Since Hangfire itself doesn't use Unity, you will need to start up Hangfire with the appropriate configuration, such as the SQL Server connection string, and then use that configuration to inform Unity how to instantiate the Hangfire interfaces. I was able to solve this problem by setting the global Hangfire configuration for SQL and then use that same Hangfire static instance to set up Unity.
Here's example code where first you will see how I start the hangfire dashboard and server with a connection string:
public void Configuration(IAppBuilder app)
{
var configuration = new Configuration(); // whatever this is for you
GlobalConfiguration.Configuration.UseSqlServerStorage(
configuration.GetConnectionString());
GlobalConfiguration.Configuration.UseActivator(
new HangfireContainerActivator(UnityConfig.GetConfiguredContainer()));
app.UseHangfireDashboard("/hangfire", new DashboardOptions
{
Authorization = new[] {new HangfireAuthorizationFilter()}
});
app.UseHangfireServer();
}
As the second example, here's the configuration of Unity for Hangfire; notice how this code is using the static JobStorage Hangfire object to instantiate any requests for JobStorage.
public static void RegisterHangfire(IUnityContainer container)
{
container.RegisterType<JobStorage>(new InjectionFactory(c => JobStorage.Current));
container.RegisterType<IJobFilterProvider, JobFilterAttributeFilterProvider>(new InjectionConstructor(true));
container.RegisterType<IBackgroundJobFactory, BackgroundJobFactory>();
container.RegisterType<IRecurringJobManager, RecurringJobManager>();
container.RegisterType<IBackgroundJobClient, BackgroundJobClient>();
container.RegisterType<IBackgroundJobStateChanger, BackgroundJobStateChanger>();
}
I believe this approach gives you the best of both worlds where you only set up your SQL Server connection once and you do it early to kick off Hangfire, but then you use that instance to tell Unity how to behave.

How to get base url without accessing a request

How to get the base URL in AspNet core application without having a request?
I know from the Request you can get the scheme and host (ie $"{Request.Scheme}://{Request.Host}" would give something like https://localhost:5000), but is it possible to get this information from anywhere else?
In other words, if I have a service class that needs to build absolute URLs, how can I get the current URL when there is not an http request available?
UPDATE: Maybe that scenario does not even make sense since the hosting URL is totally external to the application and that's why it only makes sense to extract it from the Request host..
i needed for some reason to get the base URL in Start.cs Configure, so i come up with this
var URLS = app.ServerFeatures.Get<IServerAddressesFeature>().Addresses;
You are right, hosting URL is an external information, and you can simply pass it as configuration parameter to your application.
Maybe this will help you somehow: without request, you can get a configured listening address (like http://+:5000) using the IWebHostBuilder interface. It provides access to host settings via the GetSetting method:
/// <summary>
/// Get the setting value from the configuration.
/// </summary>
/// <param name="key">The key of the setting to look up.</param>
/// <returns>The value the setting currently contains.</returns>
string GetSetting(string key);
There is a WebHostDefaults.ServerUrlsKey setting name, that allows to configure listening address. We override it when add .UseUrls extension method:
public static IWebHostBuilder UseUrls(this IWebHostBuilder hostBuilder, params string[] urls);
or define urls configuration parameter as described in the documentation (you know, by default listening is configured to localhost:5000).
So, having instance of IWebHostBuilder, you can call .GetSetting(WebHostDefaults.ServerUrlsKey) and get the current value.
,The ASP.NET Core Module generates a dynamic port to assign to the backend process. CreateDefaultBuilder calls the UseIISIntegration method. UseIISIntegration configures Kestrel to listen on the dynamic port at the localhost IP address (127.0.0.1). If the dynamic port is 1234, Kestrel listens at 127.0.0.1:1234. This configuration replaces other URL configurations provided by.
For IIS Integration, it works if you get the address after the WebHostBuilder.Build() have run.
var builder = CreateWebHostBuilder(args);
var webHost = builder.Build();
var addresses = webHost.ServerFeatures.Get<IServerAddressesFeature>().Addresses;
var address = addresses.FirstOrDefault();
AppDomain.CurrentDomain.SetData("BaseUrl", address ?? "");
webHost.Run();
and got the local Kestrel address in the HostedService like this:
string baseUrl = AppDomain.CurrentDomain.GetData("BaseUrl").ToString();
But there's a catch - this address is useless, because you can not make a request directly on this address. The IIS Integration middleware checks that only the IIS handler can make a request on this address. It produces a similar error:
<category>Microsoft.AspNetCore.Server.IISIntegration.IISMiddleware</category>
<state>'MS-ASPNETCORE-TOKEN' does not match the expected pairing token 'ed5bc610-b7b9-4c1c-9941-954d0579edfc', request rejected.</state>
And in general case (no IIS Integration) this method of getting the address does not work if you use Kestrel configured to run with a custom port (not 5000), or a dynamic port 0. In this case the address needs to be obtained in a delayed manner, only after the application started.
For this case i tried this way: In Configure method in the StartUp class, i saved in ServerAddressFeature in the private member.
private IServerAddressesFeature _serverAddressesFeature;
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
_serverAddressesFeature = app.ServerFeatures.Get<IServerAddressesFeature>();
... not related code here ...
And in the ConfigureServices method i added a dependency
public void ConfigureServices(IServiceCollection services)
{
services.AddSingleton<IServerAddressesFeature>((sp) => _serverAddressesFeature);
... not related code here ...
Then in a hosted service i obtain this saved feature using dependency injection, and use it to get the address.
It works, only get the address in the StartAsync method, not in the service constructor!
public class WarmUpService : IHostedService
{
private readonly ILogger _logger;
private readonly IServerAddressesFeature _saf;
public WarmUpService(ILogger<WarmUpService> logger, IServerAddressesFeature serverAddressesFeature)
{
_logger = logger;
_saf = serverAddressesFeature;
}
public async Task StartAsync(CancellationToken cancellationToken)
{
try
{
// the URL can be Got here
string baseUrl = _saf?.Addresses?.FirstOrDefault();
// await _WarmUp(baseUrl);
}
catch(Exception ex)
{
_logger.LogCritical(ex, "WarmUp Failed");
}
}
public Task StopAsync(CancellationToken cancellationToken)
{
return Task.CompletedTask;
}
}

How do I force GlassFish 2 to load EJBs on startup?

We're using EJB3 on GlassFish v2.
My application includes a GenericServlet called StartupServlet, which has an init method. java.util.TimerTask pollers started from this method cannot lookup facades from the InitialContext.
However if I make an HTTP request and do a lookup, it succeeds. Therefore I have a workaround now where my poller startup code makes an HTTP connection to a page which looks up the interfaces they need.
How can I rearrange my application so I don't need to use such a hack? If possible the solution needs to work on GFv3 as well.
Thanks in advance for your help!
On GF 2, I have a servlet that on start ensures that my timer is created. This looks up a remote session bean and calls it successfully from the init() (not actual code, distilled down to the important parts):
#EJB(name="TimerSessionRef", beanInterface=TimerSessionRemote.class)
public class StartTimers extends HttpServlet {
#Override
public void init() throws ServletException {
super.init();
try {
Context ctx = new InitialContext();
TimerSessionRemote timerSession = (TimerSessionRemote) ctx.lookup("java:comp/env/TimerSessionRef");
timerSession.createTimer();
} catch (NamingException ex) {
logger.blah();
}

Work with OData secured service

I want to generate entity classes and Service class of OData secured service.
In OData Java extension page it is written that I need to use org.restlet.ext.odata.Generator class that should get uri and output directory parameters.
But if my OData service is secured the generator instance is not able to generate service classes without username and password of the service.
I did not find any way to pass username and password to generator class.
I get 401 HTTP response code.
Please help.
In the org.restlet.ext.odata.Generator class, in the method main,
The following code would clear the credential details set in the setCredentials() method.
Service service = new Service(dataServiceUri);
if(service.getMetadata() == null)
{
errorMessage = "Cannot retrieve the metadata.";
}
Kindly provide a solution for this issue as I am currently unable to generate the classes for my rest service as the service is secured with an user password.
I tried the following code to generate the code for my secured service uri:
import org.restlet.ext.odata.Generator;
import org.restlet.ext.odata.Service;
import org.restlet.data.ChallengeResponse;
import org.restlet.data.ChallengeScheme;
public class ODataRestletGenerator extends Service {
public ODataRestletGenerator(String serviceUri) {
super(serviceUri);
}
public static final String APPLICATION_URI = "http://ldcigkd.xxx.yyy.corp:50033/xxx/opu/sdata/IWCNT/CUSTOMER/";
public static void main(String[] args) {
// Add the client authentication to the call
ChallengeScheme scheme = ChallengeScheme.HTTP_BASIC;
ChallengeResponse credentials = new ChallengeResponse(scheme, "user", "pwd");
new ODataRestletGenerator(APPLICATION_URI).setauth(credentials);
String[] arguments = { APPLICATION_URI, "/customer/src" };
Generator.main(arguments);
}
private void setauth(ChallengeResponse credentials) {
super.setCredentials(credentials);
}
}
In the org.restlet.ext.odata.Service subclass that is generated by OData extension, you can call setCredentials() and pass an instance of ChallengeResponse including scheme (BASIC?), login (identifier) and password (secret).