In the previous post we looked at using Kestrel to run an ASP.NET Core application, now we’re going to use Giraffe to build some services.<\/p>\n
Giraffe is an F# library to let get started by creating our application code.<\/p>\n
Replace Program.fs code with the following<\/p>\n
\r\nopen Giraffe\r\nopen Microsoft.Extensions.DependencyInjection\r\nopen Microsoft.AspNetCore.Builder\r\nopen Microsoft.AspNetCore.Hosting\r\nopen Microsoft.AspNetCore\r\n\r\nlet webApp =\r\n choose [\r\n GET >=>\r\n choose [\r\n routeCif "\/hello\/%s" (fun name -> text (sprintf "Hello %s" name))\r\n ]\r\n ]\r\n\r\ntype Startup() =\r\n member this.ConfigureServices (services : IServiceCollection) =\r\n services.AddGiraffe() |> ignore\r\n\r\n member this.Configure (app : IApplicationBuilder) =\r\n app.UseGiraffe webApp\r\n\r\n[<EntryPoint>]\r\nlet main _ =\r\n WebHost.CreateDefaultBuilder()\r\n .UseKestrel()\r\n .UseStartup<Startup>()\r\n .Build()\r\n .Run()\r\n 0\r\n<\/pre>\nIn the previous post we saw how to create the Kestrel server, so the code in main is exactly the same (apart from obviously being F#) which creates the server and calls the Startup class to configure our middleware. In this case we add Giraffe to the services and runs the Giraffe webApp HTTP handler.<\/p>\n
The webApp HTTP handler is basically our filter and routing function.<\/p>\n
Run this code up and navigate to localhost:5000\/hello\/World and we should get Hello World<\/em> displayed.<\/p>\n
We didn’t actually need the GET handler as by default the GET will be used, but it’s shown here to be a little more explicit in what is being implemented. We can also support POST methods using the same syntax as our GET code.<\/p>\n
Extending our routes<\/strong><\/p>\n
Giraffe allows us to declare multiple routes which can include static pages. Let’s start off my adding an index.html page to the “Content root path” as displayed when running the application, in my case this is the folder containing Program.fs. I’m using the following index.html<\/p>\n
\r\n<html>\r\n <body>\r\n Hello World\r\n <\/body>\r\n<\/html>\r\n<\/pre>\nNow add a new route to the route section of the webApp. i.e.<\/p>\n
\r\nchoose [\r\n routeCif "\/hello\/%s" (fun name -> text (sprintf "Hello %s" name))\r\n route "\/" >=> htmlFile "index.html"\r\n]\r\n<\/pre>\nThis has now added a route for localhost:5000\/ which returns the contents of the index.html file.<\/p>\n
A list of different routes can be seen in the source for Routing.fs<\/a>.<\/p>\n
Below is an example of using some different routes<\/p>\n
\r\nlet helloName name = text (sprintf "Hello %s" name)\r\n\r\nlet webApp =\r\n choose [\r\n GET >=>\r\n choose [\r\n \/\/ case insensitive using anonymous function\r\n routeCif "\/hello\/%s" (fun name -> text (sprintf "Hello %s" name))\r\n route "\/" >=> htmlFile "index.html" \r\n route "\/error" >=> setStatusCode 404\r\n route "\/ping" >=> text "pong"\r\n \/\/ case sensitive use function\r\n routef "\/hello2\/%s" helloName\r\n ]\r\n ]\r\n<\/pre>\nReturn from the fish (>=>) operator can be marked as different types of result types.
\nThe functions text, htmlFile and other response writes available here ResponseWriters.fs<\/a>. These include the usual suspects such as XML and JSON. Giraffe also supports Razor, see the NuGet package Giraffe.Razor<\/a>.<\/p>\n