This release brings the last batch of breaking changes we have planned before 3.0 stable. The three bigger items we have left are updating/fixing TypeScript output, reviewing code mapping and adding more documentation.

Namespace changes

We have shortened namespace names by changing every occurence of IntelliFactory.WebSharper to WebSharper. This affects base package and all extensions. Also IntelliFactory.JavaScript is renamed to WebSharper.Core.JavaScript. DLLs are similarly renamed with the exception of IntelliFactory.WebSharper.dll which is now WebSharper.Main.dll.

WebSharper.Formlets in a separate package

The Formlets library is now contained in the NuGet package WebSharper.Formlets. Its dependency, IntelliFactory.Reactive is in another new package IntelliFactory.Reactive.

JSON Sitelets

You can now create REST APIs easily by using F# types. See previous announcement.

User Session in Sitelets and Rpc functions

Up until now, the module WebSharper.Sitelets.UserSession could be used to manage user login. Unfortunately, functions in this module have two major drawbacks:

• They use ASP.NET-specific functionality, and therefore cannot be used with other hosts such as self-hosted OWIN.
• They assume that they run on the same thread that is responding to the request. This assumption is unreasonable, especially when using functions such as Content.PageContentAsync.

For these reasons, the following changes are made:

• The module WebSharper.Sitelets.UserSession is marked as obsolete.
• The type Sitelets.Context<'T> now contains a field UserSession, which can be safely used in asynchronous sitelets. Note that unlike the old UserSession, its methods are asynchronous.
• The new function WebSharper.Web.Remoting.GetContext() can be used in Rpc functions to retrieve a thread-safe user session manager. It must be called from the Rpc function's thread, but the resulting object can be used asynchronously. For example:

[<Rpc>]
let DoSomethingIfLoggedIn() =
    let ctx = Web.Remoting.GetContext()
    async {
        let! loggedIn = ctx.UserSession.GetLoggedInUser()
        match loggedIn with
        | None -> return "Error: not logged in"
        | Some username -> return! DoSomething username
    }

• This functionality is implemented both in the built-in ASP.NET module and in WebSharper.Owin.

JavaScript interop

• Previous .ToEcma() methods for converting a .NET type to its EcmaScript binding equivalent has been obsoleted. Renamed to .JS property.
• Previous .ToDotNet() methods are now a .Self property on WebShaper.JavaScript. types.
• JavaScript.Function is now a base class for all JavaScript.FuncWith... types (giving strong typing to JavaScript functions).
• Methods on JavaScript.Function has been renamed to ApplyUnsafe, CallUnsafe, BindUnsafe to avoid overloading with the strongly-typed methods on descendant classes.

WebSharper Interface Generator

• The generic helper for more than 4 type parameter is now GenericN n - fun typeParamList -> ...
• Generic % can be used to add the same type parameters to a list of members.
• Generic * can be used to add the same type parameters to a to a ClassMembers value (created by Instance [...] or Static [...]).
• These generic helpers all add type parameters in addition to previously defined ones on the members returned by the inner function, instead of overwriting the generics list.
• Type parameters are automatically renamed on library generation to avoid name clashes.

Other improvements

• A compile warning is given when a tupled or curried lambda or variable with the same types are coerced to obj. This can help avoiding some mistakes, for example writing

    New [ "compare" => fun (a, b) -> a - b ] 
  

  and passing it to JavaScript code expecting a function that takes two arguments. However, this is translated to a JavaScript function taking a single 2-element array argument. The former is the much more common scenario, so on this warning, change it to

    New [ "compare" => FuncWithArgs(fun (a, b) -> a - b) ] 
  

  to pass the right function. Otherwise, you can use the Function.As static method to wrap the lambda and and get rid of the warning.

• [<OptionalField>] attribute now can be used on class or record types. This makes all option valued fields of the type represented as present/missing JavaScript properties in the translation.

Fixes

• #340: Generic methods of a generic type used wrong type parameters for generating the member. This could have affected some of our extensions.