Introducing SwiftHtml
This time we will begin the whole lot from scratch. Within the first part of this text I’ll present you how one can setup the SwiftHtml as a package deal dependency and how one can generate HTML output primarily based on a template file. Let’s begin by making a model new executable Swift package deal.
mkdir Instance
cd "$_"
swift package deal init --type=executable
open Package deal.swift
You can even begin with a macOS Command Line Instrument from Xcode if you want, however these days I want Swift Packages. Anyway, we should always add SwiftHtml as a dependency to our package deal instantly.
import PackageDescription
let package deal = Package deal(
identify: "Instance",
platforms: [
.macOS(.v12)
],
dependencies: [
.package(url: "https://github.com/binarybirds/swift-html", from: "1.2.0"),
],
targets: [
.executableTarget(name: "Example", dependencies: [
.product(name: "SwiftHtml", package: "swift-html"),
]),
.testTarget(identify: "ExampleTests", dependencies: ["Example"]),
]
)
All proper, now we’re prepared to write down some Swift DSL code. We will begin with a very primary instance to get to know with SwiftHtml. In the principle.swift file we should always create a brand new HTML doc, then we are able to use SwiftHtml’s built-in renderer to print the html supply. 🖨
import SwiftHtml
let doc = Doc(.html) {
Html {
Head {
Title("Hey, World!")
Meta().charset("utf-8")
Meta().identify(.viewport).content material("width=device-width, initial-scale=1")
}
Physique {
Predominant {
Div {
H1("Hey, World!")
P("This web page was generated by the SwiftHtml library.")
}
}
.class("container")
}
}
}
let html = DocumentRenderer(minify: false, indent: 2).render(doc)
print(html)
As you possibly can see the code is fairly simple, particularly if you already know a bit about HTML. The SwiftHtml library tries to comply with the naming conventions as intently as attainable, so in the event you’ve written HTML earlier than this syntax ought to be very acquainted, besides that you do not have to write down opening and shutting tags, however we are able to make the most of the Swift compiler to do the boring repetative duties as an alternative of us.
Since we’re utilizing a site particular language in Swift, the compiler can type-check the whole lot at build-time, this manner it is 100% certain that our HTML code will not have syntax points. After all you possibly can nonetheless make semantic errors, however that is additionally attainable in the event you’re not utilizing a DSL. 😅
The principle benefit right here is that you simply will not be capable to mistype or misspell tags, and you do not even have to consider closing tags, however you need to use outcome builders to assemble the HTML node tree. SwiftHtml makes use of tags and it will construct a tree from them, this manner it’s attainable to effectively render your entire construction with correct indentation or minification whether it is wanted.
The DocumentRenderer object can render a doc, additionally it is attainable to create all kinds of SGML-based doc sorts, as a result of the SwiftHtml package deal comes with an abstraction layer. For those who check out the package deal construction it’s best to see that contained in the Sources listing there are a number of different directories, the core of the package deal is the SwiftSgml part, which permits builders to create different area particular languages on prime of the bottom parts. 🤔 For instance, in the event you check out the SwiftRss package deal you will note that it is a easy extension over the SwiftSgml library. You’ll be able to subclass the Tag object to create a brand new (area particular) tag with an underlying Node object to characterize a customized merchandise in your doc.
The SwiftSgml library may be very light-weight. The Node struct is a illustration of a given SGML node with a customized kind, identify and attributes. The Tag class is all about constructing a hierarchy in between the nodes. The Doc struct is a particular object which is liable for rendering the doctype declaration earlier than the foundation tag if wanted, additionally after all the doc comprises the foundation tag, which is the start of the whole lot. 😅
SwiftSgml additionally comprises the DocumentRenderer and a easy TagBuilder enum, which is a outcome builder and it permits us to outline our construction in a SwiftUI-like model.
So the SwiftHtml package deal is only a set of HTML guidelines on prime of the SwiftSgml library and it follows the W3C HTML reference guides. You need to use the output string to save lots of a HTML file, this manner you possibly can generate static web sites through the use of the SwiftHtml library.
import Basis
import SwiftHtml
let doc = Doc(.html) {
Html {
Head {
Title("Hey, World!")
Meta().charset("utf-8")
Meta().identify(.viewport).content material("width=device-width, initial-scale=1")
}
Physique {
Predominant {
Div {
H1("Hey, World!")
P("This web page was generated by the SwiftHtml library.")
}
}
.class("container")
}
}
}
do {
let dir = FileManager.default.homeDirectoryForCurrentUser
let file = dir.appendingPathComponent("index.html")
let html = DocumentRenderer(minify: false, indent: 2).render(doc)
attempt html.write(to: file, atomically: true, encoding: .utf8)
}
catch {
fatalError(error.localizedDescription)
}
This is only one method to make use of SwiftHtml, in my view static web site mills are positive, however the true enjoyable begins when you possibly can render web sites primarily based on some sort of dynamic knowledge. 🙃
Utilizing SwiftHtml with Vapor
Vapor has an official template engine referred to as Leaf plus the neighborhood additionally created a type-safe HTML DSL library referred to as HTMLKit, so why create one thing very related?
Properly, I attempted all of the obtainable Swift HTML DSL libraries that I used to be capable of finding on GitHub, however I used to be not fully happy with the at present obtainable options. A lot of them was outdated, incomplete or I merely did not like the flavour of the DSL. I needed to have a library which is freakin’ light-weight and follows the requirements, that is the rationale why I’ve constructed SwiftHtml. 🤐
How can we combine SwiftHtml with Vapor? Properly, it is fairly easy, let’s add Vapor as a dependency to our undertaking first.
import PackageDescription
let package deal = Package deal(
identify: "Instance",
platforms: [
.macOS(.v12)
],
dependencies: [
.package(url: "https://github.com/binarybirds/swift-html", from: "1.2.0"),
.package(url: "https://github.com/vapor/vapor", from: "4.54.0"),
],
targets: [
.executableTarget(name: "Example", dependencies: [
.product(name: "SwiftHtml", package: "swift-html"),
.product(name: "Vapor", package: "vapor"),
]),
.testTarget(identify: "ExampleTests", dependencies: ["Example"]),
]
)
We will want a brand new protocol, which we are able to use assemble a Tag, that is going to characterize a template file, so let’s name it TemplateRepresentable.
import Vapor
import SwiftSgml
public protocol TemplateRepresentable {
@TagBuilder
func render(_ req: Request) -> Tag
}
Subsequent, we want one thing that may render a template file and return with a Response object, that we are able to use inside a request handler once we setup the route handlers in Vapor. Since we will return a HTML string, it’s essential to set the correct response headers too.
import Vapor
import SwiftHtml
public struct TemplateRenderer {
var req: Request
init(_ req: Request) {
self.req = req
}
public func renderHtml(_ template: TemplateRepresentable, minify: Bool = false, indent: Int = 4) -> Response {
let doc = Doc(.html) { template.render(req) }
let physique = DocumentRenderer(minify: minify, indent: indent).render(doc)
return Response(standing: .okay, headers: ["content-type": "text/html"], physique: .init(string: physique))
}
}
Lastly we are able to lengthen the built-in Request object to return a brand new template renderer if we want it.
import Vapor
public extension Request {
var templates: TemplateRenderer { .init(self) }
}
Now we simply should create a HTML template file. I am normally making a context object proper subsequent to the template this manner I am going to have the ability to move round contextual variables for every template file. I am fairly pleased with this strategy to this point. ☺️
import Vapor
import SwiftHtml
struct IndexContext {
let title: String
let message: String
}
struct IndexTemplate: TemplateRepresentable {
let context: IndexContext
init(_ context: IndexContext) {
self.context = context
}
func render(_ req: Request) -> Tag {
Html {
Head {
Title(context.title)
Meta().charset("utf-8")
Meta().identify(.viewport).content material("width=device-width, initial-scale=1")
}
Physique {
Predominant {
Div {
H1(context.title)
P(context.message)
}
}
.class("container")
}
}
}
}
Lastly we simply have to write down some boilerplate code to begin up our Vapor internet server, we are able to use the app occasion and set a get request handler and render our template utilizing the newly created template renderer extension on the Request object.
import Vapor
import SwiftHtml
var env = attempt Setting.detect()
attempt LoggingSystem.bootstrap(from: &env)
let app = Utility(env)
defer { app.shutdown() }
app.get { req -> Response in
let template = IndexTemplate(.init(title: "Hey, World!",
message: "This web page was generated by the SwiftHtml library."))
return req.templates.renderHtml(template)
}
attempt app.run()
Kind of that is it, it’s best to be capable to run the server and hopefully it’s best to see the rendered HTML doc in the event you open the http://localhost:8080/
deal with utilizing your browser.
It is usually attainable to make use of one template inside one other, since you possibly can name the render methodology on a template and that template will return a Tag. The fantastic thing about this strategy is which you can compose smaller templates collectively, this manner you possibly can give you a pleasant undertaking construction with reusable HTML templates written fully in Swift. I am very happy with this straightforward resolution and looks like, for me, there isn’t any turning again to Leaf or Tau… 🤓