EventNotification support for MVC

[rynowak]

We want to add support for events via Microsoft.Framework.Notification to various components in MVC that can be consumed in process by diagnostic tools.

To start with we want to include data/events with known tooling experiences built around them. This isn't a complete list, but includes things we can start on.

Routing:

• Each route should have an event for success/failure
• Include HttpContext
• Include information about the route being executed
• Include RouteData

Action Selection:

• Event for Actions Matching Route Values (include HttpContext, include RouteData, include ActionDescriptors)
• Event for Actions Matching Constraints (include HttpContext, include RouteData, include ActionDescriptors)
• Event for final action selected (include HttpContext, include RouteData)

Action Invoker:

• Event for before/after a filter (include ActionContext, Filter, data from context Exception, Cancelled, etc)
• Event for invoking action (include ActionContext, Controller, MethodInfo, Arguments)
• Example: Logging: Filters #1629 (comment)

Model Binding:

• Needs design - see: Logging: Model Binding #1566 (comment)
• Goal here would be to include what data is bound to each model value/property and what data source it came from. This might require enhancing ValueProviderResult

Content-Negotation/ObjectResult:

• Events for the content type chosen/conneg failed. Include inputs (Accept, Content-Type, Formatters, Model-Type, Result)

View Engine:

• Event for view search - include ViewEngine, Search paths, values used
• Example: Logging: ViewEngine #1563 (comment)

Startup:

• Event for action discovery - include ActionDescriptors

[rynowak]

/cc @avanderhoorn - this is where we're going to get started

[rynowak]

Added some data points for:

Action Method begin/end
Action Result begin/end
View Found (ViewResult)
View Not Found (ViewResult)

This is all we're going to do here for beta-7 e384938

[pranavkm]

@rynowak also brought this another use for this in a hallway discussion - we could use event notification instead of the interface contract we use for BrowserLink \ page instrumentation. This would require raising events for

• View rendering - with details of view kind (partial \ full), path, and rendered view contents
• Layout rendering
• Templates?

Will need to speak to @jodavis to figure out the feasibility of doing this.

[avanderhoorn]

For Microsoft.AspNet.Mvc.ViewResultViewFound, is it possible to get the location where it found the View?

Also is it possible to get a quick one line description of each event and what you should be using it to determine?

Here is a template that might make it faster to fill out if it helps?

• BeforeAction - Microsoft.AspNet.Mvc.BeforeAction
  • Use when: ...
  • Can determine: What route was matched to a given Action
  • Provides access to: ActionDescriptor, HttpContext, RouteData
• AfterAction - Microsoft.AspNet.Mvc.AfterAction
  • Use when: ...
  • Provides access to: ActionDescriptor, HttpContext
• BeforeActionMethod - Microsoft.AspNet.Mvc.BeforeActionMethod
  • Use when: ...
  • Can determine: What objects (i.e. the finial model binding result) where passed into a given Action
  • Provides access to: ActionContext, ActionArguments
• AfterActionMethod - Microsoft.AspNet.Mvc.AfterActionMethod
  • Use when: ...
  • Provides access to: ActionContext, ActionResult
• ViewResultViewNotFound - Microsoft.AspNet.Mvc.ViewResultViewNotFound
  • Use when: ...
  • Can determine: The locations that the view engine searched for the view
  • Provides access to: ActionContext, Result, ViewName, SearchedLocations
• ViewResultViewFound - Microsoft.AspNet.Mvc.ViewResultViewFound
  • Use when: ...
  • Can determine: The view data that is being passed to a given view
  • Provides access to: ActionContext, Result, ViewName, View

[rynowak]

IView is passed to Microsoft.AspNet.Mvc.ViewResultViewFound and includes the view path.

[avanderhoorn]

@rynowak Great!

[rynowak]

We've done all planned work here for beta8. Any new requests will be tracked separately.