Shaver

Shaver is lightweight F# library for Suave.io web server built on the top of the Razor Engine and provides some extra features like template composing, setting custom return codes, localization resources support or server thread auto-localization by client Accept-Language header.


Keywords
F#, fsharp, suave, razor, templating, http, web, localization
License
Apache-2.0
Install
Install-Package Shaver -Version 1.3.1

Documentation

Shaver

Shaver

Shaver is lightweight library for Suave.io web server, built on top of the Razor Engine and provides some extra features like template composing, setting custom return codes, localization resources support or server thread auto-localization by client Accept-Language header.

Installation

First install NuGet package

Install-Package Shaver

or using Paket

nuget Shaver

How to use

This tutorial covers only Shaver additional features and considers you are familiar with Razor Engine syntax.

Templating

All functions related to templating are located in Shaver.Razor module.

Single page

To render single page, use Shaver in exactly the same way as you would use Razor in Suave:

open Shaver.Razor

type MyModel = { Message: string }

let webPart : WebPart = singlePage "SinglePage.html" { Message = "Hello Shaver"}

Single page with custom HTTP code

In some cases you just want to return your page with other than HTTP 200 response code (e.g. for failed authorization):

singlePageWithCode HTTP_401 "Unauthorized.html" { Message = "Sorry, man"}

Master page

You do not have to rely just on single template. Templates can be composed together to create whole page without having "supermodels" (models wrapping other models) in your code.

Let`s have two small templates:

Menu.html
<ul>
  @foreach(var item in @Model) {
    <li>@item</li>
  }
</ul>
Content.html
<div>Hello @Model.Name let`s make some noise in @Model.City</div>

And now we create master template with placeholders for both partial templates:

Master.html
<body>
  <h1>@Model.Title</h1>
  <div id="menu">{{{SectionOne}}}</div>
  <div id="content">{{{SectionTwo}}}</div>
</body>

Ok, now it is time to compose everything together and create full page:

let menuItems = ["About"; "Contact us"] 
type MyContentModel = { Name: string; City: string }
type MyMasterModel = { Title: string }

let webPart : WebPart =
  [
      ("SectionOne", partial "Menu.html" menuItems);
      ("SectionTwo", partial "Content.html" { Name = "Roman"; City = "Prague"  })
  ] 
  |> masterPage "masterPage.html" { Title = "Welcome" }

Master page with custom HTTP code

To return custom HTTP code, use masterPageWithCode function:

 ...
 |> masterPageWithCode HTTP_401 "masterPage.html" { Title = "An error occured" }

Empty partials

Sometimes you may want to have some section of master template rendered as empty string. You do not have to create new empty template. Just use empty instead:

let webPart : WebPart =
  [
      ("SectionOne", empty);
      ("SectionTwo", empty)
  ] 
  |> masterPage "masterPage.html" { Title = "Welcome" }

Nested master pages

Your master templates can be composed using other master templates by using nested function:

let webPart : WebPart =
  [    
    ("SectionOne", partial "Menu.html" menuItems);
    ("SectionTwo",
      [("NestedOne", partial "partialOne.html" { One = "Hello Nested One" });
       ("NestedTwo", partial "partialTwo.html" { Two = "Hi Nested Two" })
      ] |> nested "nestedMasterPage.html" {Nested = "Hi Nested"});
  ]
  |> masterPage "masterPage.html" { Title = "Welcome" }

Localization

Shaver library provides functionality to enable auto-localization by parsing Accept-Language request header. All related functions are located in Shaver.Localization module.

Current UI culture

To set current culture (System.Threading.Thread.CurrentThread.CurrentUICulture) use localizeUICulture function as shown in example below:

...
open Shaver.Razor
open Shaver.Localization

let webPart =
  localizeUICulture >> // <-- Setting current UI culture
  choose [
    path "/" >=> singlePage "SinglePage.html" { Message = "Hello Shaver"}
  ]

startWebServer defaultConfig webPart

Current culture

If you want to change current culture, use localizeCulture instead:

...
localizeCulture >> // <-- Setting current culture
  choose [
    path "/" >=> singlePage "SinglePage.html" { Message = "Hello Shaver"}
  ]
...

Resources

Models are great for sending dynamic data to templates, but usually you don`t want to pass static texts for labels, headings, etc... Having separated localized resource files is much better and you can even use them from frontend!

Let`s create two localization json files and put them in <Root>\Strings (default) folder:

Greetings.json
{
  "Welcome" : "Welcome, english speaking visitor!"
}
Greetings.cs-CZ.json
{
  "Welcome" : "Nazdar, tady mluvíme česky!"
}

Now we can use these values directly in our template:

<h1>{{{$:Greetings:Welcome}}}</h1>

As you may expect, these values will be replaced with values from correct localized resource json file.

Please note:

  • Correct file selection is based on current UI culture, so don`t forget to use localizeUICulture function as described in Localization section.
  • By default, files are expected to be located in <Root>\Strings folder. This can be changed:

    Shaver.Resources.folder <- "MyResourcesFolder"
    
  • You can have many culture specific variations.

    • Greetings.json (default for all cultures)
    • Greetings.en.json (default for all english)
    • Greetings.en-US.json (US english)
    • Greetings.en-GB.json. (Great Britain english)

    Search logic works from the most specific culture to default one. So if your page visitor comes from United States (having culture code set to en-US), Greetings.en-US.json is used (exact match!). If he comes from Australia (having culture code set to en-AU), Greetings.en.json is used, because it is the default resource for english visitors. If he comes from France (having culture code set to fr-FR), default Greetings.json is used (no french resource found).

  • Do not forget to set Copy to Output Directory on all your localization json files

Configuration

If you don`t feel comfortable with {{{ and }}} for templating, you can configure your own opening and closing tags:

Shaver.Razor.openTag <- "[[["
Shaver.Razor.closeTag <- "]]]"

Your template code would look like this:

<h1>[[[$:Greetings:Welcome]]]</h1>

Please note that this would also affect section definition in templates:

<body>
  <h1>@Model.Title</h1>
  <div id="menu">[[[SectionOne]]]</div>
  <div id="content">[[[SectionTwo]]]</div>
</body>

Contribution

Did you find any bug? Missing functionality? Please feel free to Create issue or Pull request.