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Intercepting requests and providing resources to Xamarin.Forms.WebView

I want to show some XHTML documents that reference some resources (style sheets, scripts, images, etc). These resources are local, but they do not exist on the file system - instead, they are generated by my application.
Using Android.Webkit.WebView and Android.Webkit.WebViewClient, I can intercept requests and provide these resources flawlessly, using something like this:
internal class MyWebViewClient : WebViewClient
{
public override WebResourceResponse ShouldInterceptRequest (WebView view, string url)
{
/* logic to create a resource stream for the requested url */
return new WebResourceResponse (mimeType, encoding, generatedStream);
}
}
Can I achieve something similar using Xamarin.Forms.WebView and its related classes? If so, how? I haven't noticed in the API documentation any methods that look like they provide equivalent behavior.

The Xamarin.Forms WebView control is very basic at present. The class members show that you wouldn't be able achieve what you are wanting to do.
You can load a HTML resource etc here that is quite useful in determining how to reference local files, if you do decide and go down that route.
Do note, however, that in Xamarin.Forms v1.2.2.6243 on Android the Source property is incorrectly set for URLs. For instance, if you navigate to www.yahoo.com and do a few clicks on that site, you will see some query string parameters etc. However, on Android this always comes back as Source property being www.yahoo.com. Xamarin have created a temporary fix for this, however you have to include and implement your own custom renderer at present to overcome this.

SignalR multiple hubs on different paths in same application?

I have an application which contains multiple hubs all on unique paths, so when calling the default :
routes.MapHubs("path", new HubConfiguration(...));
It blows up saying that the signalr.hubs is already defined (as mentioned here MapHubs not needed in SignalR 1.01?).
Now I can understand that it should only be called once, but then you will only get 1 path, so is there any way to handle a path per hub scenario? like how with MVC you specify the controller and action? so something like:
routes.MapHub<SomeHub>("path", new HubConfiguration(...));
== Edit for more info ==
It is mentioned often that you should never need to call this map hubs more than once, and in most scenarios I can agree, however I would not say that this is going to be the case for all applications.
In this scenario it is a website which at runtime loads any plugins which are available, each plugin is exposed the dependency injection framework to include its dependencies and the route table to include its routes. The hubs may have nothing to do with each other (other than the fact that they are both hub objects). So the hubs are not all known up front and are only known after the plugins are loaded, and yes I could wait until after this and try binding the hubs there, however then how do I have custom routes for each one then?
This seems to be a case of SignalR trying to abstract a little too much, as I dont see it being a bad idea to have custom routes rather than the default "/signalr", and as the routes all have different responsibilities it seems bad to have one entry route for them all.
So anyway I think the question still stands, as I dont see this as being a bad use case or bad design it just seems to be that I want to be able to have a route with a hub applied to it, much like in mvc you apply a controller and action to a route.

You shouldn't need more than the signalr.hubs route. If you point your browser to that route, you will see it automatically finds all public types assignable to IHub and creates a JavaScript proxy for them. You can interact with different hubs by name from JavaScript, i.e. if you have the following Hub:
public class GameHub : Hub
You can connect to that specific hub by doing:
var gameHubProxy = $.connection.gameHub;
You can also explicitly specify a name for your hub by adding the HubNameAttribute to the class:
[HubName("AwesomeHub")]
public class GameHub : Hub
You can then retrieve the specific proxy by doing
var awesomeHubProxy = $.connection.awesomeHub;
UPDATE:
I'm not sure whether SignalR will be able to run on multiple paths in the same application. It could potentially mess things up and the default assembly locator won't be able to pick up hubs loaded at runtime anyway.
However, there is a solution where you can implement your own IAssemblyLocator that will pick up hubs from your plugin assemblies:
public class PluginAssemblyLocator : DefaultAssemblyLocator
{
private readonly IEnumerable<Assembly> _pluginAssemblies;
public PluginAssemblyLocator(IEnumerable<Assembly> pluginAssemblies)
{
_pluginAssemblies = pluginAssemblies;
}
public override IList<Assembly> GetAssemblies()
{
return base.GetAssemblies().Union(_pluginAssemblies).ToList();
}
}
After you've loaded your plugins, you should call MapHubs and register an override of SignalRs IAssemblyLocator service:
protected void Application_Start(object sender, EventArgs e)
{
// Load plugins and let them specify their own routes (but not for hubs).
var pluginAssemblies = LoadPlugins(RouteTable.Routes);
RouteTable.Routes.MapHubs();
GlobalHost.DependencyResolver.Register(typeof(IAssemblyLocator), () => new PluginAssemblyLocator(pluginAssemblies));
}
NOTE: Register the IAssemblyLocator AFTER you've called MapHubs because it will also override it.
Now, there are issues with this approach. If you're using the static JavaScript proxy, it won't be re-generated every time it's accessed. This means that if your /signalr/hubs proxy is accessed before all plugins/hubs has been loaded, they won't be picked up. You can get around this by either making sure that all hubs are loaded by the time you map the route or by not using the static proxy at all.
This solution still requires you to get a reference to your plugin assemblies, I hope that's feasible...

Writing a generic WCF service client config/endpoint checker?

I have a client application that consumes a number of services. It's not always immediately obvious when a service is down or incorrectly configured. I own the service side code and hosting for most of the services, but not all of them. It's a real mixed bag of client proxies - different bindings (basichttp/wshttp/nettcp), some have been generated using svcutil.exe, while others are made programatically with ChannelFactory where the contract is in a common assembly. However, I always have access to the address, binding and contract.
I would like to have a single component in my client application that could perform a basic check of the binding/endpoint config and the service availability (to show in some diagnostic panel in the client). As a minimum I just want to know that there is an endpoint at the configured address, even better would be to find out if the endpoint is responsive and supports the binding the client is trying to use.
I tried googling and was surprised that I didn't find an example (already a bad sign perhaps) but I figured that it couldn't be that hard, all I had to do was to create a clientchannel and try to open() and close() catch any exceptions that occur and abort() if necessary.
I was wrong - in particular, with clients using BasicHttpBinding where I can specify any endpoint address and am able to open and close without any exceptions.
Here's a trimmed down version of my implementation, in reality I'm returning slightly more detailed info about the type of exception and the endpoint address but this is the basic structure.
public class GenericClientStatusChecker<TChannel> : ICanCheckServiceStatus where TChannel : class
{
public GenericClientStatusChecker(Binding binding, EndpointAddress endpoint)
{
_endpoint = endpoint;
_binding = binding;
}
public bool CheckServiceStatus()
{
bool isOk = false;
ChannelFactory<TChannel> clientChannelFactory = null;
IClientChannel clientChannel = null;
try
{
clientChannelFactory = new ChannelFactory<TChannel>(_binding, _endpoint);
}
catch
{
return isOk;
}
try
{
clientChannel = clientChannelFactory.CreateChannel() as IClientChannel;
clientChannel.Open();
clientChannel.Close();
isOk = true;
}
catch
{
if (clientChannel != null)
clientChannel.Abort();
}
return isOk;
}
}
[Test]
public void CheckServiceAtNonexistentEndpoint_ExpectFalse()
{
var checker = new GenericClientStatusChecker<IDateTimeService>(new BasicHttpBinding(), new Endpointaddress("http://nonexistenturl"));
// This assert fails, because according to my implementation, everything's ok
Assert.IsFalse(checker.CheckServiceStatus());
}
I also tried a similar technique with a dummy testclient class that implemented ClientBase with the same result. I suppose it might be possible if I knew that all my service contracts implemented a common CheckHealth() method, but because some of the services are outside my control, I can't even do that.
So, is it even possible to write such a simple general purpose generic service checker as this? And if so how? (And if not, why not?)
Thanks!

Have you looked at WCF Discovery?
WCF Discovery allows a client to search for a service based on
different criteria including contract types, binding elements,
namespace, scope, and keywords or version numbers. WCF Discovery
enables runtime and design time discovery. Adding discovery to your
application can be used to enable other scenarios such as fault
tolerance and auto configuration.
For a first attempt, you could query the endpoint to see if it supports the expected contract.
The big benefit is that you can have the client “discover” which service it wants to talk to at runtime. Which removes a lot of the client side configuration errors that you are likely used to seeing.

You need to check out SO-AWARE. It is a web service management tool that can manage SOAP or REST WCF-based service across your organization. Further it has a Test Workbench!
Here are a couple of videos that show it off too:
Part 1
Part 2
To put it in perspective, this is so complex that these people make a living doing it, I don't think it's something you want to realistically build on your own.

How can I get the URL of the current page from within a C# App_Code class?

I have a logging class that, well, logs things. I would like to add the ability to automatically have the current page be logged with the messages.
Is there a way to get the information I'm looking for?
Thanks,

From your class you can use the HttpContext.Current property (in System.Web.dll). From there, you can create a chain of properties:
Request
Url and RawUrl
The underlying object is a Page object, so if you cast it to that, then use any object you would normally use from within a Page object, such as the Request property.

It's brittle and hard to test but you can use System.Web.HttpContext.Current which will give you a Request property which in turn has the RawUrl property.

public static class MyClass
{
public static string GetURL()
{
HttpRequest request = HttpContext.Current.Request;
string url = request.Url.ToString();
return url;
}
}
I tried to break it down a little :)

In the past I've also rolled my own logging classes and used Console.Writeln() but really there are a number of good logging options that already exist so why go there? I use NLog pretty much everywhere; it is extremely flexible with various log output destinations including console and file, lots of log format options, and is trivial to set up with versions targeting the various .net frameworks including compact. Running the installer will add NLog config file options to the Visual Studio Add New Item dialog. Using in your code is simple:
// declare in your class
private static Logger logger = LogManager.GetCurrentClassLogger();
...
// use in your code
logger.Debug(() => string.Format("Url: {0}", HttpContext.Current.Request.Url));

OAuth in C# as a client

I've been given 6 bits of information to access some data from a website:
Website Json Url (eg: http://somesite.com/items/list.json)
OAuth Authorization Url (eg: http://somesite.com/oauth/authorization)
OAuth Request Url (eg: http://somesite.com/oauth/request)
OAuth Access Url (eg: http://somesite.com/oauth/access)
Client Key (eg: 12345678)
Client Secret (eg: abcdefghijklmnop)
Now, I've looked at DotNetOpenAuth and OAuth.NET libraries, and while I'm sure they are very capable of doing what I need, I just can't figure out how to use either in this way.
Could someone post some sample code of how to consume the Url (Point 1.) in either library (or any other way that may work just as well)?
Thanks!

I also just started working with OAuth a month ago and was also confused by all these libraries. One thing I realized about these libraries is that they're quite complicated (as you have found out). Another thing that makes it hard is that there wasn't a lot of example (it was worse in my case because I was trying to implement a Provider and not a Client).
Originally, I wanted to use the latest OAuth 2.0 but the only .NET library out there that implements it is DotNetOpenAuth. It's probably one of the most complete .NET OAuth library out there but it'll take too long for me to understand (due to not knowing WCF, MVC, etc). I have since downgraded to OAuth 1.0a because I found these examples for DevDefined OAuth. I don't know about you but I found it easier to learn from examples.
It looks like you only want to implement a Client so make sure to look at the Consumer examples. Try to compile the examples and ignore the Provider examples because you don't need them and it'll make you more confused. Be patient. If you're still confused, it might be a good idea to look at some of the libraries made for other languages as they might have easier to understand documentations.

OK, I know your last post was months ago, but in case you were still working on this (or for people like me who would have loved to see an answer to this question), here's some information regarding the NullReferenceException you encountered creating the OAuth request:
The null reference comes from the IServiceLocator that is used to resolve dependencies. If you don't explicitly pass one into the constructor, it uses the static property ServiceLocator.Current in the Microsoft.Practices.ServiceLocation namespace.
This is one of the many pitfalls of using static methods and global state, is you hide issues like this from the consumer of your API. So if you haven't specified a default service locator, then null is returned, resulting in the NullReferenceException.
So to fix this issue, I wired up an implementation of IServiceLocator that uses StructureMap (one of the many IoC containers available) as the container. Lastly, you will need to register instances for two interfaces: ISigningProvider and INonceProvider. Luckily, several standard implementations exist in the OAuth.Net.Components assembly, such as GuidNonceProvider and HmacSha1SigningProvider.
The resulting code looks like something like this:
var container = new Container();
container.Configure(a => a.For<INonceProvider>().Use<GuidNonceProvider>());
container.Configure(a => a.For<ISigningProvider>()
.Use<HmacSha1SigningProvider>()
.Named("signing.provider:HMAC-SHA1"));
var locator = new StructureMapAdapter(container);
ServiceLocator.SetLocatorProvider(delegate { return locator; });
I realize this isn't the final solution to your original question (I'm still working on getting it working myself), but I hope it gets you a few steps further. And if you've long abandoned this implementation altogether... well, happy coding anyway!

For OAuth 2.0:
I learned that it's easiest to just put up the authentication page in an HTML window then trap the returned access_token. You can then do that using in client-side web browser.
For example, in MonoTouch it would be:
//
// Present the authentication page to the user
//
var authUrl = "http://www.example.com/authenticate";
_borwser.LoadRequest (new NSUrlRequest (new NSUrl (authUrl)));
//
// The user logged in an we have gotten an access_token
//
void Success(string access_token) {
_web.RemoveFromSuperview();
var url = "http://www.example.com/data?access_token=" + access_token;
// FETCH the URL as needed
}
//
// Watch for the login
//
class Del : UIWebViewDelegate
{
public override void LoadingFinished (UIWebView webView)
{
try {
var url = webView.Request.Url.AbsoluteString;
var ci = url.LastIndexOf ("access_token=");
if (ci > 0) {
var code = url.Substring (ci + "access_token=".Length);
_ui.Success (code);
}
} catch (Exception error) {
Log.Error (error);
}
}
}