Giraffe

A functional ASP.NET Core micro web framework for building rich web applications.

Read this blog post on functional ASP.NET Core for more information.

Table of contents

• About
• Getting Started
• Documentation
• Sample applications
• Benchmarks
• Building and developing
• Contributing
• Nightly builds and NuGet feed
• Blog posts
• Videos
• License
• Contact and Slack Channel
• Support

About

Giraffe is an F# micro web framework for building rich web applications. It has been heavily inspired and is similar to Suave, but has been specifically designed with ASP.NET Core in mind and can be plugged into the ASP.NET Core pipeline via middleware. Giraffe applications are composed of so called HttpHandler functions which can be thought of a mixture of Suave's WebParts and ASP.NET Core's middleware.

If you'd like to learn more about the motivation of this project please read my blog post on functional ASP.NET Core (some code samples in this blog post might be outdated today).

[!TIP] Check the release notes document to know how the system is evolving, and to get more information about breaking changes.

Who is it for?

Giraffe is intended for developers who want to build rich web applications on top of ASP.NET Core in a functional first approach. ASP.NET Core is a powerful web platform which has support by Microsoft and a huge developer community behind it and Giraffe is aimed at F# developers who want to benefit from that eco system.

It is not designed to be a competing web product which can be run standalone like NancyFx or Suave, but rather a lean micro framework which aims to complement ASP.NET Core where it comes short for functional developers. The fundamental idea is to build on top of the strong foundation of ASP.NET Core and re-use existing ASP.NET Core building blocks so F# developers can benefit from both worlds.

You can think of Giraffe as the functional counter part of the ASP.NET Core MVC framework.

Getting Started

Using dotnet-new

The easiest way to get started with Giraffe is by installing the giraffe-template package, which adds a new template to your dotnet new command line tool:

dotnet new install "giraffe-template::*"

Afterwards you can create a new Giraffe application by running dotnet new giraffe.

If you are using dotnet core 2.1.4, you will need to specify the language: dotnet new giraffe -lang F#

For more information about the Giraffe template please visit the official giraffe-template repository.

Doing it manually

Install the Giraffe NuGet package*:

PM> Install-Package Giraffe

*) If you haven't installed the ASP.NET Core NuGet package yet then you'll also need to add a package reference to Microsoft.AspNetCore.App:

PM> Install-Package Microsoft.AspNetCore.App

Alternatively you can also use the .NET CLI to add the packages:

dotnet add package Microsoft.AspNetCore.App
dotnet add package Giraffe

Next create a web application and plug it into the ASP.NET Core middleware:

open System
open Microsoft.AspNetCore.Builder
open Microsoft.AspNetCore.Hosting
open Microsoft.Extensions.Hosting
open Microsoft.Extensions.Logging
open Microsoft.Extensions.DependencyInjection
open Giraffe

let webApp =
    choose [
        route "/ping"   >=> text "pong"
        route "/"       >=> htmlFile "/pages/index.html" ]

type Startup() =
    member __.ConfigureServices (services : IServiceCollection) =
        // Register default Giraffe dependencies
        services.AddGiraffe() |> ignore

    member __.Configure (app : IApplicationBuilder)
                        (env : IHostEnvironment)
                        (loggerFactory : ILoggerFactory) =
        // Add Giraffe to the ASP.NET Core pipeline
        app.UseGiraffe webApp

[<EntryPoint>]
let main _ =
    Host.CreateDefaultBuilder()
        .ConfigureWebHostDefaults(
            fun webHostBuilder ->
                webHostBuilder
                    .UseStartup<Startup>()
                    |> ignore)
        .Build()
        .Run()
    0

Instead of creating a Startup class you can also add Giraffe in a more functional way:

open System
open Microsoft.AspNetCore.Builder
open Microsoft.AspNetCore.Hosting
open Microsoft.Extensions.Hosting
open Microsoft.Extensions.DependencyInjection
open Giraffe

let webApp =
    choose [
        route "/ping"   >=> text "pong"
        route "/"       >=> htmlFile "/pages/index.html" ]

let configureApp (app : IApplicationBuilder) =
    // Add Giraffe to the ASP.NET Core pipeline
    app.UseGiraffe webApp

let configureServices (services : IServiceCollection) =
    // Add Giraffe dependencies
    services.AddGiraffe() |> ignore

[<EntryPoint>]
let main _ =
    Host.CreateDefaultBuilder()
        .ConfigureWebHostDefaults(
            fun webHostBuilder ->
                webHostBuilder
                    .Configure(configureApp)
                    .ConfigureServices(configureServices)
                    |> ignore)
        .Build()
        .Run()
    0

For more information please check the official Giraffe documentation.

Sample applications

Demo apps

There is a few sample applications which can be found in the samples GitHub repository. Please check the README.md there for further information.

Live apps

dusted.codes

My personal blog https://dusted.codes is also built with Giraffe and ASP.NET Core and all of the source code is published on GitHub for further reference.

More sample applications will be added in the future.

Benchmarks

Giraffe is part of the TechEmpower Web Framework Benchmarks and will be listed in the official results page in the upcoming Round 17 for the first time.

Unofficial test results are currently available on the TFB Status page.

As of today Giraffe competes in the Plaintext, JSON and Fortunes categories and has been doing pretty well so far, even outperforming ASP.NET Core MVC in Plaintext and JSON at the time of writing.

The latest implementation which is being used for the benchmark tests can be seen inside the TechEmpower repository.

Giraffe is also featured in Jimmy Byrd's dotnet-web-benchmarks where we've run earlier performance tests.

Building and developing

Giraffe is built with the latest .NET Core SDK, which works on Windows, macOS and Linux out of the box.

You can either install Microsoft Visual Studio or JetBrains Rider which both come with the latest .NET Core SDK or manually download and install the .NET Core SDK and use the .NET CLI or Visual Studio Code with the Ionide extension to build and develop Giraffe.

The easiest way to build Giraffe is via the .NET CLI.

Run dotnet build from the root folder of the project to restore and build all projects in the solution:

dotnet build

Running dotnet test from the root of the project will execute all test projects referenced in the solution:

dotnet test

Contributing

Help and feedback is always welcome and pull requests get accepted.

TL;DR

• First open an issue to discuss your changes
• After your change has been formally approved please submit your PR against the master branch
• Please follow the code convention by examining existing code
• Add/modify the README.md as required
• Add/modify unit tests as required
• Please document your changes in the upcoming release notes in RELEASE_NOTES.md
• PRs can only be approved and merged when all checks succeed (builds on Windows and Linux)

Discuss your change first

When contributing to this repository, please first discuss the change you wish to make via an open issue before submitting a pull request. For new feature requests please describe your idea in more detail and how it could benefit other users as well.

Please be aware that Giraffe strictly aims to remain as light as possible while providing generic functionality for building functional web applications. New feature work must be applicable to a broader user