I'm debugging a project where Microsoft.Owin.Hosting.WebApp class is used. This is a legacy code. At the same time the whole project is hosted inside IIS web application. When app pool is recycled, I'm receiving a massive exception eruption into the log file, and it says that "Exception has been thrown by the target of an invocation."
The line it points is no more than
App = WebApp.Start(url);
This problem occurs only on recycling. When I manually stop the pool and start it after a couple of seconds, it works well (until next recycle). I'm pretty sure the problem is that WebApp class is trying to register itself onto a port (defined by the url parameter) that is still registered after WebApp's previous instance (so that, for example, recycling without interruption of service is not possible).
Is there any way to check if port is already registered? To make it free?
The WebApp class is from Microsoft.Owin.Hosting. You'd only use that when self-hosting. It does not make sense to have that in an web app running in IIS.
The way Owin/Katana starts when using IIS as a host is through a PreApplicationStartAttribute. Using it, a Module is added that calls the Owin/Katana initialization code (finds Startup.cs, runs configuration, etc).
The dll that does this is Microsoft.Owin.Host.SystemWeb.
(I have no reference for this, I had to ask the source)
In short, if you are running in IIS, you should use the Microsot.Owin.Host.SystemWeb nuget package. You should be able to remove that line: App = WebApp.Start.
Related
We have a pretty large asp.net LOB web application. The problem is that every time the app pool is started (whether its the first time, or if the app pool is recycled) it's takes up to 10 seconds or more to spin up and hit the first page. This leaves you in a state of looking at a white page and a loading spinner until IIS is ready to serve up the page. This isnt the end of the world because it's only normally a one off thing and only the first person experiences this. I'm just wondering if there is an event that we can hook into to serve up a page and show the user some type of simple splash screen to give them some type of feedback instead of a loading state.
Has anybody got any ideas on how to hook this into IIS/asp.net?
You can use the application initialization module. If you run IIS 8.0 or higher it is built-in, if you run IIS 7.5 you can download and install it.
Hopefully you are running .NET 4.5. Set the application start mode to AlwaysRunning. Then enable preload.
And then here you will want to add this to your web.config in your system.WebServer section
<applicationInitialization remapManagedRequestsTo="Startup.htm" skipManagedModules="true" >
<add initializationPage="/default.aspx" />
</applicationInitialization>
The startup.htm is your default loading screen. If anyone tries to access it when they go to the web application it will be remapped to that. Just add a simple JavaScript refresh location script to it.
This link should give you everything you need. Again, I am assuming you are on a newer version of ASP.NET and IIS.
http://www.iis.net/learn/get-started/whats-new-in-iis-8/iis-80-application-initialization
We want to use a Service Worker to perform client-side source code transformation for development purposes. We want to use Babel to transpile ES6+/ES2015 files to ES5 modules.
However, including the browser version of babel in a Service Worker using importScripts causes the following errors:
GET http://localhost:8080/babel-core/browser.js net::ERR_FAILED
Uncaught NetworkError: Failed to execute 'importScripts' on 'WorkerGlobalScope': The script at 'http://localhost:8080/babel-core/browser.js' failed to load.
So, the question is, how to correctly import babel into a Service Worker.
edit: This is not the obvious NetworkError, as we can change the content of the file into something simple, which enables us to actually load and execute the file. Also, the file can be loaded with a normal <script> tag.
edit2: To get this message, check out this repository https://github.com/onsetsu/lively4-core.git, start a local server at port 8080 and finally load http://localhost:8080/bootworker.html. We are currently using Chrome 44.
How about my experiment here https://github.com/bahmutov/babel-service - you can see the demo at https://babel-service-demo.herokuapp.com/.
I am using feature tests to detect supported features and transpile the intercepted code selectively. Of course this is just a start and only maps default parameters to babel plugins, but more features could be mapped.
Also, the people behind feature tests are discussing the selective transpile https://github.com/getify/es-feature-tests/issues/9
As a general rule, using a service worker for something crucial for a site's functionality isn't a recommended practice. Service workers are intended to be a progressive enhancement, and your sites should be designed to still be functional if the associated service worker isn't available.
Even in browsers which support service workers, there might not be one controlling your page if a user shift-reloads or if it's the very first navigation, before the service worker has had a chance to take control.
To answer your specific question, the ServiceWorkerGlobalScope under which service worker code executes exposes different functionality vs. a normal page's global scope, and it would appear that something in the browser.js script you're trying to import assumes functionality that's only available in a normal page. Unfortunately, Chrome's DevTools, even with the debugger enabled, doesn't reveal which specific statement is causing the error, so I can't say which exact statement(s) are invalid.
We have a SPA web application that we're trying to convert into a WinJS project as a native Windows Store app. For most part, the Javascript is working except for DOM manipulations deemed unsafe.
One thing that does not appear apparent is, how can the start page of the app (e.g. index.html) be supplied with query string and hash parameters? Our site main page is designed to behave differently based on parameters.
e.g. index.html?contextId=xxxxx#enviroment=xxxxx
I tried adjusting the value in package.appxmanifest to no avail. It will throw errors on query strings, and hash parameters will silently not persist.
UPDATE: Project background
A brief about what our app does, and then why the above naive desire won't work and the answer below how we went about this issue.
Our web app is a highly-dynamic data-driven application that completely relies on data to figure out what to render. Therefore the ?contextId=xxxxx parameter is so crucial as it tells our system to load the data which further informs what kinds of visual components to load and it goes on recursively to form wildly different UIs.
We were looking to therefore find some means to supply these parameters like traditional command-line parameters to the same executable to produce different UIs. And thus different "apps" by mere changes in those parameters. Like a "config transform" mechanism for web.config in ASP.NET web projects, that would be most welcome.
However further testing showed it is not possible; a single Windows store app project has a GUID that is supplied into the packaged app bundle. Building the same project multiple times with different "build config" would just mean overwriting a previous installation since they are the same app with increasing version numbers. The answer details how we went about this.
Windows Store apps don't work with URI parameters when launched from their primary tile. In that case, you should make sure that the app defaults to suitable values, e.g., if you were thinking to supply defaults in the manifest, then default to those in the app's activation handler for the ActivationKind.launch case when eventObject.detail.arguments is empty.
There are two other ways to launch an app that can supply other arguments.
First is to launch via a secondary tile. When you create the tile from the app (which is subject to user consent), you supply the launch arguments. In your activation handler, for ActivationKind.launch, those args will be in the eventObject.detail.arguments property.
Second is to launch the app through a URI association. You use a custom schema for this, which is declared in the manifest. The app will then see ActivationKind.protocol and eventObject.detail.uri will contain the full URI including any parameters. A URI launch can be done from another app, by entering the URI into a browser address bar, or through a shortcut that a user could configure on the Start screen.
The first step is to convert our Windows (8.1) Store project into a Universal app structure, which would then spin off a separate Windows Phone WinJS project (this is nice when we wish to target Windows Phone later) and a shared project.
Practically everything from the Windows Store project is moved to the shared project (including default.html or index.html). What remains in the Windows Store project is a customised config.js carrying the parameters
window.customWin8 = {
contextId: xxxxxxxxxx,
customParam: 'xxxxxxxxxx'
};
The downstream modules that sense for query string/hash parameters would then fall back to this alternative object if it exists to pick up the data it needs.
Now, for every differing app we wish to deploy, that would for now seem to require a separate Windows Store project so it gets its own GUID and won't conflict with other apps. All these projects would reference the very same shared project thanks to the Universal structure Visual Studio affords. The only down side is it seems Visual Studio 2013 does not have a direct UI method to make this referencing to the share project and has to be hand code into the jsproj file.
<Import Project="..\Common.Shared\Common.Shared.projitems" Label="Shared" />
With this adjustment they can all build and package with their isolated "build config".
I have an http handler built and running on my website server. Code in flex generates a http request then navigates to the handler, which generates and streams back file information for the user to download.
Basically the request sends image data and the return result is a pptx stream with the image data in a powerpoint slide.
This worked fantastically this morning until about an hour ago. I have no idea what changed, but every swf I am building which attempts to access this handler is now giving me:
* Security Sandbox Violation *
Connection to https://g1.localhost/Turm/BounceBack.aspx halted - not permitted from https://g1.localhost/Turm/FlashApps/ImageAndExporting.swf?debug=true
I even fully qualified the BounceBack.aspx name (it was a relative url until just now) in case something was confusing the flash player, but as you can see, the url request and the swf are loaded from exactly the same domain (even the same virtual app in the web domain).
I have even added the physical filepath as a 'trusted folder' in my flash player security settings.
What gives? Anyone have any suggestions?
Using the Apache 4.9.1 SDK and latest version of flashplayer.
As mentioned, this worked all day yesterday and this morning. I cannot figure out what has changed, but am having no luck resolving the issue, source code has not changed.
Finally figured out what changed. I move the navigation to my ASPX handler into a seperate method that delays invoation till after a UI update. Becuase I use the same ui components for printing as well as exporting, I tested the updates with the print feature and that worked without error. About an our later, I noticed the handlers were failing. Since the url request is not handled inside a UI interaction event (Like MouseEvent.CLICK) the flash player was preventing the call. Once I moved the navigation back into the event handler, the sandbox violation went away.
If you ask me, not a very good error message due to the actual problem encountered, but ... you learn something every day.
Please read the following in the Visual Studio 2012 context:
I have two projects--one is a website (File --> New Website) and another is a console application (File --> New Project --> Windows --> Console Application). I am the author of the former.
The standalone app fakes the input by hardcoding it, runs through some code, and creates an output. It uses dlls from a local installation of software that I have installed on my machine to generate this output.
I read on MSDN that I cannot add a console app to a website solution in a useful manner. So, if I compile the console app to output a dll instead of an exe, can I reference that dll in my website? How can I do this exactly? I would need to pass the input value from the website to the dll, and return meaningful results from the dll. Is this possible?
Yes, you describe a feasible way to solve this. You need to create a class library project, add source code from console application to it, except the the class that has static Main method and modify (add to) that source code such that there is a class that you will be able instantiate from the code in your web application after you add the class library assembly to the web application as a reference. This class will have a method with appropriate parameters, that you will call. All this assuming that the task that console application code performs is fast and will not create noticeable delay in the web application response. If the task takes a long time, you will either have to run it in a background thread or move it outside the web application - the latter is significantly more involved.