Add some missing APIs for HttpContext, HttpRequest and HttpResponse

[Maples7]

Summary

Most primary APIs of HttpContext, HttpRequest and HttpResponse are provided, which is fantastic! And some missing APIs could be considered to be added to make this adapter more universal.

Motivation and goals

Some missing APIs are frequently used for .NET Framework and adding them to the adapter will make the migration smoother and more doable for large projects.

In scope

For HttpContext:

• DisposeOnPipeline Enable HttpContext.DisposeOnPipelineCompleted #88
• CurrentHandler Consider supporting handler/module infrastructure #146
• CurrentNotification Consider supporting handler/module infrastructure #146
• IsCustomErrorEnabled Enable HttpContext.IsCustomErrorEnabled #152
• IsDebuggingEnabled Add HttpContext.IsDebuggingEnabled #106
• PreviousHandler Consider supporting handler/module infrastructure #146
• Timestamp Add HttpContext.Timestamp #104
• GetGlobalResourceObject Transition from web.config to appsettings #23
• GetLocalResourceObject Transition from web.config to appsettings #23
• GetSection Transition from web.config to appsettings #23
• RewritePath Add HttpContext.RewritePath #145
• SkipAuthorization Enable HttpContext and friends to modify endpoint metadata #147
• SetSessionStateBehavior Enable HttpContext and friends to modify endpoint metadata #147

For HttpRequest:

• AcceptTypes Add HttRequest.AcceptTypes #101
• ClientCertificate Enable HttpRequest.ClientCertificate #148
• FilePath Add missing API: HttpRequest.FilePath #278
• Files Add HttpRequest.Files and supporting types #103
• Item[String] Add HttpRequest.Params and this[] #105
• Params Add HttpRequest.Params and this[] #105
• PathInfo Add missing API: HttpRequest.FilePath #278
• PhysicalPath Enable HttpRequest APIs dependent on VirtualPathUtility #149
• ReadEntityBodyMode Enable HttpRequest.ReadEntityBodyMode/GetBuffer[ed|less]InputStream() #150
• RequestContext Enable HttpRequest.RequestContext #151
• SaveAs Add HttpRequest.SaveAs #135

For HttpResponse:

• AppendCookie Add HttpResponse APIs (ClearHeaders/WriteFile/TransmitFile/etc) #102
• AppendToLog Enable HttpResponse.AppendToLog #153
• ApplyAppPathModifier Enable HttpRequest APIs dependent on VirtualPathUtility #149
• BinaryWrite Add HttpResponse APIs (ClearHeaders/WriteFile/TransmitFile/etc) #102
• ClearHeaders Add HttpResponse APIs (ClearHeaders/WriteFile/TransmitFile/etc) #102
• BufferOutput Enable HttpContext and friends to modify endpoint metadata #147
• IsRequestBeingRedirected Add HttpResponse APIs (ClearHeaders/WriteFile/TransmitFile/etc) #102
• SubStatusCode Add HttpResponse APIs (ClearHeaders/WriteFile/TransmitFile/etc) #102
• RedirectPermanent Add HttpResponse APIs (ClearHeaders/WriteFile/TransmitFile/etc) #102
• Expires Enable HttpCachePolicy #155
• SuppressFormsAuthenticationRedirect Enable HttpResponse.SuppressFormsAuthenticationRedirect  #154
• TransmitFile Add HttpResponse APIs (ClearHeaders/WriteFile/TransmitFile/etc) #102
• WriteFile Add HttpResponse APIs (ClearHeaders/WriteFile/TransmitFile/etc) #102
• WriteSubstitution

Risks / unknowns

I can imagine not all of them make sense for ASP.NET Core, or fit .NET Core's design philosophy, or are easy to implement.

Examples

More APIs covered, more large projects could be benefited.

[twsouthwick]

After looking into these APIs, some are definitely doable while others are on the harder side and some others are probably not something we can really mimic.

HttpContext

We should probably do:

• RewritePath
• Timestamp
• IsDebuggingEnabled (probably could check if it is production or not)
• GetSection (although we'd need to explore how the configuration would be used here) Transition from web.config to appsettings #23

The following are very much tied to IIS. ASP.NET Core does not have a concept of handlers, the SkipAuthorization is tied to IIS authorization, and the SetSessionStateBehavior would only be used in IHttpModules I think

• CurrentHandler
• CurrentNotification
• IsCustomErrorEnabled
• PreviousHandler
• GetGlobalResourceObject Transition from web.config to appsettings #23
• GetLocalResourceObject Transition from web.config to appsettings #23
• SkipAuthorization
• SetSessionStateBehavior

HttpRequest

We should probably do:

• AcceptTypes
• FilePath
• Files
• Item[String]
• Params
• PathInfo
• ReadEntityBodyMode
• SaveAs

These may be harder, but possible:

• RequestContext
• ClientCertificate
• PhysicalPath (this doesn't seem to map well with the abstracted file structure of core, but maybe there's an equivalent)

HttpResponse

We should probably do:

• AppendCookie
• BinaryWrite
• ClearHeaders
• IsRequestBeingRedirected
• RedirectPermanent
• TransmitFile
• WriteFile

These may be harder, but possible:

• AppendToLog
• ApplyAppPathModifier (appears to be used for cookieless sessions, which probably doesn't apply on core)
• BufferOutput (we currently require opt in to this with metadata, not sure if/how we should handle this)
• SubStatusCode (this is not transmitted to the client, but does end up in logs. This would require a change to the hosting module here to pass a substatus through)
• Expires (this would require HttpCachePolicy infrastructure to enable)
• SuppressFormsAuthenticationRedirect (this is a property that the FormsAuthenticationModule hooks into to rewrite 401 to 302)
• WriteSubstitution (this would need some of the HttpCachePolicy infrastructure to handle properly)

[adityamandaleeka]

Triage: we consider SubStatusCode to be obsolete so we wouldn't enable support for it without a strong business justification.

[adityamandaleeka]

Let's do a first pass of the "straightforward" ones and then file separate issues for the more involved ones.