Constructing stylesheets utilizing Leaf – The.Swift.Dev.

December 22, 2022

1

A fast CSS demo venture

The very first step is so as to add Leaf as a dependency to your venture. It is best to be aware that Leaf 4 is just not completed but and these model new options are solely obtainable from the tau pre-release.


import PackageDescription

let package deal = Bundle(
    title: "myProject",
    platforms: [
       .macOS(.v10_15)
    ],
    dependencies: [
        
        .package(url: "https://github.com/vapor/vapor", from: "4.32.0"),
        .package(url: "https://github.com/vapor/leaf", .exact("4.0.0-tau.1")),
        .package(url: "https://github.com/vapor/leaf-kit", .exact("1.0.0-tau.1.1")),
    ],
    targets: [
        .target(name: "App", dependencies: [
            .product(name: "Leaf", package: "leaf"),
            .product(name: "Vapor", package: "vapor"),
        ]),
        .goal(title: "Run", dependencies: ["App"]),
        .testTarget(title: "AppTests", dependencies: [
            .target(name: "App"),
            .product(name: "XCTVapor", package: "vapor"),
        ])
    ]
)

We’re able to import Leaf in your Swift recordsdata, since there’s a new LeafFileMiddleware obtainable as a part of Leaf we’ll create some publicly obtainable template recordsdata and use this middleware to render them. Create a brand new Public listing inside the basis folder of the venture and place an new index.html file there. You can too use a .leaf extension, however for the sake of simplicity (and Xcode syntax highlighting causes) we’ll use the .html extension this time.

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta title="viewport" content material="width=device-width, initial-scale=1">
    <title>#(title)</title>
    <hyperlink rel="stylesheet" href="/css/fashion.css">
</head>
<physique>
    <header>
        <h1>#(title)</h1>
    </header>
</physique>
</html>

Fairly fundamental HTML5 boilerplate code, besides that we’ll print the title utilizing a Leaf tag. We’ll set a worth for this context variable by means of some Swift code in a second. Within the head part we additionally import our css/fashion.css stylesheet file. Now you must create a css folder contained in the Public listing and place a fashion.css file inside it.

* {
    margin: 0;
    padding: 0;
}
physique {
    font-family: -apple-system, system-ui, BlinkMacSystemFont, "Helvetica", "Segoe UI", Roboto, Ubuntu;
    font-size: 16px;
    line-height: 1.4em;
    background: #(background);
}
h1 {
    padding: #(padding);
}
@media (max-width: 599px) {}
@media (min-width: 600px) {}
@media (min-width: 900px) {}
@media (min-width: 1200px) {}
@media (min-width: 1800px) {}

Since this file is “secretly” a leaf template file we are able to use the #(variable) syntax to print out values. We’re going to move a background colour key and a padding key with some customized values as context variables.

Now let me present you the right way to configure this new LeafFileMiddleware, so we are able to render each our html and css templates.

import Vapor
import Leaf
    
public func configure(_ app: Software) throws {

    if !app.surroundings.isRelease {
        LeafRenderer.Possibility.caching = .bypass
    }

    LeafFileMiddleware.defaultMediaType = .html
    LeafFileMiddleware.processableExtensions = ["leaf", "html", "css", "js"]
    LeafFileMiddleware.contexts = [
        .css: [
            "background": "#eee",
            "padding": "16px",
        ],
        .html: [
            "title": "Hello world!"
        ],
    ]
    
    if let lfm = LeafFileMiddleware(publicDirectory: app.listing.publicDirectory) {
        app.middleware.use(lfm)
    }
    app.views.use(.leaf)
}

First we disable the cache, however that is a reasonably apparent chunk of code, subsequent we set the default media sort to html. This will likely be used to set the Content material-Kind header if the file extension within the request is an unknown sort. The processableExtensions property will inform the LeafFileMiddleware to course of and render solely these recordsdata, every thing else with a special extension will likely be streamed identical to once you use a daily FileMiddleware.

As you’ll be able to see we are able to set completely different context values for particular media varieties, in our case all of the css recordsdata can use the background and padding properties and each html file can benefit from the title context variable. Additionally it is attainable to set them by means of a subscript syntax:

LeafFileMiddleware[.css] = [
    "background": "green",
    "padding": "16px",
]

LeafFileMiddleware[.html] = [
    "title": "Hello world!"
]

The final step is to create the precise middleware with a publicDirectory argument. This listing is the placement the place the system will search for publicly obtainable recordsdata and if wanted they are often processed as common Leaf templates. You can too setup listing indexing by means of the LeafFileMiddleware, however that is a special matter.

Should you navigate to the http://localhost:8080/index.html tackle you must see your rendered index.html file with the precise stylesheet utilized to it. In fact you’ll be able to register a customized route and render your templates utilizing the same old Assets / Views location if wanted, however I simply needed to indicate you this cool trick, because it permits us to serve public recordsdata utilizing a extra dynamic strategy.

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