I have a .NET 2.0 ClickOnce application that runs in a corporate environment and it's setup to work via Windows Authentication.
So the users download the app via ClickOnce and then it connects to an IIS server and communicates via Web Service calls.
The problem is that for every single call there is a double handshake. The first call yields a 401 and invites the client to negotiate. The second call succeeds since the client sends the authentication token.
Is there anyway to eliminate this double handshake? Because it put a tremendous overhead on the latency of the application and makes it seem very sluggish.
Thanks
There actually is a solution, it turns out: WebRequest.PreAuthenticate
Check out an article by Rick Strahl.
This "double handshake" is a integral part of NTLM's challenge response model. Your only option would be to change the authentication type.
Alternatively, you try re-using the connection for web service calls.
Related
We've been experiencing some deadlocks when working with interconnected ASP.NET WebApis on the same IIS server. We'd like to know if this is somehow an expected behavior, due to hosting all APIs on the same server and same Application Pool, since we have managed to avoid the issue by moving either WebApi to a different pool; or if there's something wrong with our code.
For production, we will probably host the APIs on different server or pools, but still we'd like to understand why this is happening. Our main concern is that, if it's our faulty code, the issue may be reproduced on a larger scale, even if the hosting setup is correct.
We have created a little solution to reproduce the deadlock, hosted in GitHub.
The reproduction steps are as follow:
WebClient executes multiple HTTP request in parallel WebApi1.
WebApi1 executes an HTTP request to WebApi2.
WebApi2 executes an HTTP request to WebApi3.
WebApi3 simply returns a string.
The expected behavior would be that all requests are eventually resolved.
The actual behavior is that, certain requests gets completed, while some others will fail, due to a TaskCancelledException which seems to be due to the requests timing out.
The only article that I was able to find that seems to mention the same issue is from 2014: "Do Not Send ServerXMLHTTP or WinHTTP Requests to the Same Server", I believe that this is the issue we are experiencing, how can we confirm this?
Context
We've been assigned the task to create a centralized authentication server for multiple internal APIs of the company we work at.
We are using IdentityServer3 with reference tokens, so when some API requests a second API using reference tokens, the second API will request the authentication server for token validation which reproduces the issue.
I have added the IdentityServer tag, since this could be a common issue when doing multiple APIs communication and using reference tokens. Sample on GitHub.
Just one observation: you are using HttpClient as a static member for every Controller and according to this HttpClient is not guaranteed to be thread-safe
In IIS, I have an ASP.net web application that makes many behind-the-scenes calls to an IIS-hosted WCF service.
I never had any issues during development. However, since deploying to a few test servers at work, our tester was reporting that some of the calls were seemingly randomly failing. I verified that indeed, some of those behind the scenes webapp->service calls were failing with a "(417) Expectation Failed". Hitting the back-button and attempting the action again always worked.
A common solution I kept seeing online was https://stackoverflow.com/a/7358457/1669011
After adding that to my web config, the error continued to happen, but instead of returning a 417, would end up returning the results of my web.config's applicationInitialization remapManagedRequestsTo page.
I feel like the web.config fix I mentioned above has just allowed my web application to accept the full body of the response rather than failing when it realised it wasn't the wcf response it was expecting.
So if random services in WCF are returning the results of remapped requests that occur during Application Initialization, does that indicate that my WCF services in IIS are constantly totally shutting down?
What might cause my WCF service to randomly be in a state of "application initialization"? I'm hoping this is just a server issue and nothing to do with my application, as this has come out of nowhere and is risking an upcoming deploy.
Thanks for any assistance
My guess would be time (or very serious exceptions).
Specifically, if the server hosting the WCF service is not being hit often enough, it will shut down the application. Follow the instructions here to ensure the WCF site is not being unloaded: How to keep a WCF site online?.
If it's exceptions, you have not provided enough information to diagnose the issue.
I have following scenario:
User request for certain resource on server, This request is long running task and very like 2~3 seconds to 10 seconds. We issue a JobTicket to user, As our user want to wait.
On receiving request we store that request in persistence storage and issue a token to user as JobTicket (GUID).
User make connection with Hub to get information about that GUID.
In Background:
We have WAS Hosted as well as Windows Service to perform some operation on that request.
On complete, WAS Hosted/Windows Service call our Web Application that job has been completed.
From there based on job Ticket we identify which user and on its connection we let user know its job has been completed.
Now we have farm of servers, we are using Windows Server On Prem ServiceBus 1.1 which is working fine, But challenge we have is that we are not able to intercept ServiceBus based backplane message broadcast and message is going to all the client. As we have farm, user intermediately may have drop connection and connected to other server based on load balancer so we need to have scale out using Service Bus as its kind of seamless to integrate and we are also using for our internal purpose in our application so we don't want to user any other mix in complex solution.
I have tried using IHubPipelineModule but still Scale out message broadcast not passing thru that, I tried to hookup SignalR code directly and debug thru it but its taking long. I don't want to mess-up something arbitrary in actual code. As I can see that in OnReceive I can see message are coming, but not able to follow further. I just need small mechanism that I can intercept broadcast message and make sure that it goes to client it intended and not all the client by wasting resources, and security concern as well.
Please help me on this issue, it's kind of stuck from last 4 days and not able to come to any solution and same time I want to go with establish pattern and don't want to fork any special build for this kind of small issues which I am sure one of you expert knows how I can do that seamlessly.
Thanks,
Shrenik
After lots of struggling and not finding straight forward way, I have found the way as below for someone else in future it might help.
Scenario:
1. Web Farm: Host External User facing Web Pages
2. Backend Process: Which is mix of WebApi, SharePoint, Windows Service etc.
User from Web Page submit some request and get a unique id as return back. Internally on receiving request, we queue that request to Service Bus using TopicClient for processing.
There are pool of Windows Service watching on Message on Service Bus using SubscriptionClient and process that message. On completion of process which can run from 5 seconds to 30 seconds and some cases even more. We need to inform client that its job done if its waiting on web page or waiting for completion notification.
In this story, We are using SignalR to push job completion notification to client.
Now my earlier problem is How I let know from windows service to web application that job is done so send notification to client who submitted request.
One way is we hosted another hub internally in web application, Windows service act as client and call web application hosted hub, and in that hub method it will call external facing hub method to propagate message to specific client who submitted request, for which we are using Single user Group.
And as we have register service bus as backplane it will propagate to other servers and then appropriate client will get notification. So this is ideal solution and should work in most cases.
In above approach we have one limitation that, how Windows Service connect to Web Client, as we donot have windows auth, but we have openid based auth with ADFS. Now in such case Web Application required special code in which provide separate userid or password for windows service to communicate or have windows authentication also allowed for that hub for service account of windows service.
I was trying and trying how to remove all this hopes between interserver communication and again management of extra security.
So I did below with simplicity, though it tooks me whole night to find our internal of SignalR. But it works:
Approach is to send message directly to ServiceBus Backplane, and as all Web Server already hooked-up with ServiceBus backplane then they will get message.
Unfortunately SignalR doesn't provide such mechanism to send message directly to Backplane. I think its on pub/sub model so they don't want somebody to hack in their system :). or its violation of their pattern, but its make sense, in my case because of different roles and security, I have simplify code as below:
Create a ServiceBusMessageBus instance in my code, Same way as Below: Though I have created separate instance and store till lifetime of Windows Service, so I don't create instance every time:
ServiceBusMessageBus serviceBusBackplane = new ServiceBusMessageBus(new DefaultDependencyResolver(), new ServiceBusScaleoutConfiguration(connectionString, appName));
Create a ClientHubInvocation Object: This is a message which actually get created in SignalR infrastructure when Backplane based message broadcast:
ClientHubInvocation hubData = new ClientHubInvocation
{
Args = new object[] { msg },
Hub = "JobStatusHub",
Method = "onJobStatus",
State = null,
};
Create a Message object which accept by ServiceBusMessageBus.Publish, Yes, so this is a method which actually get called on base class ScaleoutMessageBus.Publish. This class is actually responsible for sending message to topic and other subscribers on other server nodes. Why not use that directly. Now to create Message Object, You need following code:
Message backplaneMessage = new Message(
sourceId,
"hg-JobStatusHub." + name,
new ArraySegment(Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(hubData))));
In above second parameter is something interesting,
In case if you want to publish to all the client then syntax is "h-", in my case specific group user, so syntax is "hg-.. You can check the code here: https://github.com/SignalR/SignalR/blob/bc9412bcab0f5ef097c7dc919e3ea1b37fc8718c/src/Microsoft.AspNet.SignalR.Core/Infrastructure/PrefixHelper.cs
Publish your message to backplane directly as below:
await serviceBusBackplane.Publish(backplaneMessage);
I wish this PrefixHelper class have been public.
Remember: This is not recommended way and doent insulate from future upgrade for SignalR, as its internal they may change so any upgrade might come with small hazale to change this code. But in summary this works. Hope SignalR Team provide some mechanisam out of box to send message directly to backplane instead.
Thanks
I have an ASP.NET Webform which currently calls a Java WebService. The ASP.NET Webform is created/maintained inhouse, whereas the Java WS is a package solution where we only have a WS interface to the application.
The problem is, that the Java WS is sometimes slow to respond due to system load etc. and there is nothing I can do about this. So currently at the moment there is a long delay on the ASP.NET Webform sometimes if the Java-WS is slow to respond, sometimes causing ASP.NET to reach its timeout value and throw the connection.
I need to ensure data connectivity between these two applications, which I can do by increasing the timeout value, but I cannot have the ASP.NET form wait longer than a couple of seconds.
This is where the idea of a queuing system comes into place.
My idea is, to have the ASP.NET form build the soap request and then queue it in a local queue, where then a Daemon runs and fires off the requests at the Java-WS.
Before I start building something from scratch I need a couple of pointers.
Is my solution viable ?
Are there any libraries etc already out there that I can achieve this functionality with ?
Is there a better way of achieving what i am looking for ?
You can create a WindowsService hosting a WCF service.
Your web app can them call the WCF methods of your Windows Service.
Your windows service can call the java web service methods asynchronously, using the
begin/End pattern
Your windows service can even store the answers of the java web service, and expose them through another WCF methods. For example you could have this methods in your WCF service:
1) a method that allows to call inderectly a java web service and returnd an identifier for this call
2) another method that returns the java web service call result by presenting the identifier of the call
You can even use AJAX to call the WCF methods of your Windows Service.
You have two separate problems:
Your web form needs to learn to send a request to a service and later poll to get the results of that service. You can do this by writing a simple intermediate service (in WCF, please) which would have two operations: one to call the Java service asynchronously, and the other to find out whether the async call has completed, and return the results if it has.
You may need to persistently queue up requests to the Java service. The easiest way to do this, if performance isn't a top concern (and it seems not to be), is to break the intermediate service in #1 into two: one half calls the other half using a WCF MSMQ binding. This will transparently use MSMQ as a transport, causing queued requests to stay in the queue until they are pulled out by the second half. The second half would be written as a Windows service so that it comes up on system boot and starts emptying the queue.
you could use MSMQ for queuing up the requests from you client.
Bear in mind that MSMQ doesn't handle anything for you - it's just a transport.
All it does is take MSMQ messages and deliver them to MSMQ queues.
The creation of the original messages and the processing of the delivered messages is all handled in your own code on the sending and receiving machines: the destination machine would have to have MSMQ installed plus a custom service running to pick them up and process them
Anyway there is a librays for interop with MSQM using JAVA : http://msmqjava.codeplex.com/
Another way could be you can create a queue on one of your windows box and then create a service that pick up the messages form the Queue and foreward them to the Java service
I'm looking into building an ASP.NET MVC application that exposes (other than the usual HTML pages) JSON and XML REST services, as well as Web Sockets.
In a perfect world, I would be able to use the same URLs for the Web Sockets interface as I do for the other services (and determine which data to return by what the user agent requests) but, knowing that IIS wasn't built for persistent connections, I need to know if there's a way that I can accept (and possibly even handshake) the Web Sockets connection and then pass the connection off to another service running on the server.
I do have a workaround in mind if this isn't possible that basically involves using ASP.NET to check for the Web Sockets connection upgrade headers, and responding with a HTTP/1.1 302 Found that points to a different host that has my Web Sockets service configured to directly listen to the appopriate endpoint(s).
If I completely understand your goal, I believe you can use the IIS7/7.5 Application Request Routing module to accomplish this.
Here's a quick reference: http://learn.iis.net/page.aspx/489/using-the-application-request-routing-module/
Rather than 302 responses you could use ISAPI_rewrite to direct to an appropriate endpoint (and manipulate the HTTP header to get it there)
http://www.isapirewrite.com/docs/
Otherwise no, IIS cannot natively pass off an HTTP connection. The current MSFT method is to use a 302 or something else that is intercepting the raw socket and performing header manipulation prior to sending to IIS (or whatever other application)
It strikes me that this would be a better question to ask Microsoft than to ask us. Web Sockets is new technology, and rather than looking for a hack, you might want to ask Microsoft how they plan to support it. IIS is their software. Poke around on http://iis.net (maybe in http://forums.iis.net) and see what you learn.
The way to do this is to use a unique Session ID that is associated with the Http Session. From the description, it seems like you might want to scope this to a single HttpApplication instance, but this is not necessary (you may also persist a session across many application instances). Anyway, this session ID needs to be attached somehow to each Http Request (either with a cookie, querystring, static variable with the HttpApplication instance, form data). Then you persist the identifying information about the Http session somewhere with the ID.
This identifying information may vary depending on your needs but could entail the entire http request or just some stripped down representation that serves your particular purpose.
Using this SessionID somewhere in the Http request allows you to restore whatever information you need to call and interact with the appropriate services. The instances of the services may also need to be scoped to the session as well.
Basically, what I am suggesting is that you NOT directly pass the Http connection to an external process, but instead pass the necessary data to the external process, and allow create a mechanism for sending callback data. I think looking into the mediator pattern may be helpful for you in understanding what I mean here. http://en.wikipedia.org/wiki/Mediator_pattern . I hope this helps.