Navs

The Navs Family

Navs is a router family for .NET applications. The core library is UI-agnostic; the adapters bind it to Avalonia, FuncUI and Terminal.Gui.

• Navs — core router, route table, guards, history and cache.
• UrlTemplates — URL and route-pattern parsing.
• Navs.Avalonia — Avalonia controls.
• Navs.FuncUI — Avalonia.FuncUI components.
• Navs.Terminal.Gui — Terminal.Gui controls.
• Navs.CSharp — C#-friendly facade.
• UrlTemplates.CSharp — C#-friendly facade for URL templates.

Navs (F#)

open System
open System.Threading
open Navs
open Navs.Router

let routes = [
    Route.define<string>("home", "/", fun _ _ -> "Home")
    Route.define<string>("about", "/about", fun _ _ -> "About")
    Route.define<string>(
        "guid",
        "/:id<guid>",
        fun context _ -> async {
            do! Async.Sleep 90
            return
                match context.GetParam<Guid>("id") with
                | ValueSome id -> $"Guid {id}"
                | ValueNone -> "No GUID"
        }
    )
]

let router =
    match Router.createDefault(routes) with
    | Ok router -> router
    | Error errors -> invalidOp $"Invalid routes: %A{errors}"

let result =
    router.Navigate("/about") CancellationToken.None
    |> fun task -> task.GetAwaiter().GetResult()

match result with
| Ok _ -> printfn "Current view: %A" router.Snapshot.Content
| Error error -> printfn "Navigation failed: %A" error

Navigate returns a CancellableTask<Result<...>>. Pass the token when you invoke it. The router exposes its current state through router.Snapshot and publishes changes through router.Changed.

Navs (C#)

using Navs.CSharp;

var routes = new[]
{
    Route.Define<string>("home", "/", (context, navigable) => "Home"),
    Route.Define<string>("about", "/about", (context, navigable) => "About")
};

var router = Router.Create(routes);
var outcome = await router.NavigateAsync("/about");

if (outcome.IsSuccess)
{
    Console.WriteLine(router.Snapshot.Content);
}
else
{
    Console.WriteLine(outcome.Error?.Code);
}

C# receives NavigationOutcome; it does not need to handle F# Result or ValueOption. TryBuildLink and IsActive generate links and answer active-route questions, and TryGetParam<T>/GetParamValues<T> read typed parameters from the route context or the snapshot.

Navs.Avalonia

open System.Threading
open Avalonia.Controls
open Navs
open Navs.Router
open Navs.Avalonia

let block text =
    let value = TextBlock()
    value.Text <- text
    value :> Control

let routes = [
    Route.define<Control>("home", "/", fun _ _ -> block "Home")
    Route.define<Control>("about", "/about", fun _ _ -> block "About")
]

let router = AvaloniaRouter(routes) :> IRouter<Control>

let outlet = RouterOutlet()
outlet.Router <- Some router

router.Navigate("/") CancellationToken.None |> ignore

Navs.FuncUI

open Avalonia.FuncUI.DSL
open Avalonia.FuncUI.Types
open Navs
open Navs.Router
open Navs.FuncUI

let routes = [
    Route.define<IView>("books", "/books", fun _ _ -> TextBlock.create [])
    Route.define<IView>("about", "/about", fun _ _ -> TextBlock.create [])
]

let router = FuncUIRouter(routes) :> IRouter<IView>
let outlet = RouterOutlet.create(router)

Navs.Terminal.Gui

open Terminal.Gui.Views
open Navs
open Navs.Router
open Navs.Terminal.Gui

let routes = [
    Route.define<Window>("home", "/", fun _ _ -> Window())
    Route.define<Window>("about", "/about", fun _ _ -> Window())
]

let router = TerminalGuiRouter(routes) :> IRouter<Window>
let outlet = RouterOutlet(router)

UrlTemplates

UrlTemplates parses URL templates and URLs. Navs compiles route patterns at router creation, so matching does not reparse templates on every navigation.

open UrlTemplates.RouteMatcher

let template = "/api/v1/profiles/:id<int>?optionalKey<guid>&requiredKey!#hash"
let url = "/api/v1/profiles/2345?requiredKey=2#hash"

match RouteMatcher.matchStrings template url with
| Ok (parsedTemplate, urlInfo, urlMatch) ->
    printfn "%A" parsedTemplate
    printfn "%A" urlInfo
    printfn "%A" urlMatch
| Error errors -> printfn "%A" errors

UrlTemplates (C#)

UrlTemplates.CSharp exposes the same operations through Try... methods, typed parameters and structured errors, with no F# types in the signatures.

using UrlTemplates.CSharp;

if (UrlTemplate.TryParse("/api/v1/profiles/:id<int>", out var template, out var templateError))
{
    if (RouteMatcher.TryMatch(template!, "/api/v1/profiles/2345", out var match, out var errors))
    {
        match!.TryGetPathParam<int>("id", out var id);
        Console.WriteLine(id); // 2345
    }
}