Sep 24, 2017
Tutorial: How to use Leaf
Yeey time to learn leaf β a templating language to easily generate views!
You can find the result of this tutorial on github here
This tutorial is a natural follow-up of How to set up a Vapor 2 project. You can either go for that tutorial first and come back or just skip it and read on π
1. Create a new project
Vapor toolbox is so nice it letβs you easily create new projects using any git-repo as a template. Since we will build upon the outcome of the aforementioned tutorial, we will create a new project using it as a template:
vapor new yourProjectName --template=vaporberlin/my-first-route --branch=vapor-2NOTE: You can see what vapor toolbox is all capable of by typing vapor --help in your terminal :)
Our command will create a project with the name yourProjectName using my-first-route from vaporberlin as a template (thanks vapor toolbox π€π» π€π» ).
2. Generate the Xcode project
Before we generate an Xcode project we would have to add the Leaf-Provider as a dependency and also change the package name within Package.swift:
// swift-tools-version:4.0import PackageDescriptionlet package = Package(
name: "yourProjectName", // changed
products: [
.library(name: "App", targets: ["App"]),
.executable(name: "Run", targets: ["Run"])
],
dependencies: [
.package(url: "https://github.com/vapor/vapor.git", .upToNextMajor(from: "2.1.0")), // don't forget that comma π
.package(url: "https://github.com/vapor/leaf-provider.git", .upToNextMajor(from: "1.1.0")) // added
],
targets: [
.target(name: "App", dependencies: ["Vapor", "LeafProvider"],
exclude: [
"Config",
"Public",
"Resources",
]
),
.target(name: "Run", dependencies: ["App"]),
.testTarget(name: "AppTests", dependencies: ["App", "Testing"])
]
)
Now in the terminal at the root directory yourProjectName/ execute:
vapor update -yIt may take a bit fetching the dependency, generating the Xcode project and opening it for you. But when done you should have a project structure like this:
yourProjectName/
βββ Package.swift
βββ Sources/
β βββ App/
β β βββ Routes/
β β β βββ Routes.swift
β β βββ Setup/
β β βββ Config+Setup.swift
β β βββ Droplet+Setup.swift
β βββ Run/
βββ Tests/
βββ Config/
βββ Public/
βββ Dependencies/
βββ Products/3. Configure your project to be able to use Leaf
Our first step is to add the LeafProvider in our Setup/Config+Setup.swift:
import LeafProvider // addedextension Config {
public func setup() throws {
try setupProviders()
try setupPreparations()
} /// Configure providers
private func setupProviders() throws {
try addProvider(LeafProvider.Provider.self) // added
} /// Add all models that should have their
/// schemas prepared before the app boots
private func setupPreparations() throws {}
}
Next is to set leaf as a view renderer anywhere within Config/droplet.json:
{
... "//": "The type of view renderer that drop.view will use",
"//": "leaf: Pure Swift templating language created for Vapor.",
"//": "static: Simply return the view at the supplied path",
"view": "leaf",
...
}
4. Create your first template
Our view renderer leaf is expecting a directory called Resources/ and right underneath it a directory called Views/ to hold all view-files. So you will end up with a structure like the following: yourProjectName/Resources/Views/
NOTE: They have to be directories (blue folder) and not groups (yellow folder). I created them in terminal with mkdir -p Resources/Views
You may have to re-generate your Xcode project with vapor xcode -y in order to let Xcode see your new directories. When done in Resources/Views/ create a new file named myview.leaf with following code:
<!DOCTYPE html>
<html>
<head>
<title>Leaf</title>
</head>
<body> <h1> My first leaf template! </h1> </body>
</html>5. Implement a route to serve the view
In your Routes/Routes.swift add a new route, letβs call it.. π€
import Vaporextension Droplet {
func setupRoutes() throws { get("name") { req in
return "Ethan Hunt"
} get("age") { req in
return "\(23)"
} get("json") { req in
return try JSON(node: ["name": "Martin J. Lasek", "age": 26])
} get("view") { req in
return try self.view.make("myview")
}
}
}
If you now hit cmd + r or the play button on top of Xcode, it will start the application. The console in Xcode tells you where. For me itβs 127.0.0.1/8001
NOTE: The port from where you can reach your app is defined within Config/server.swift β you can change it as you like and re-run the app :)
If you now fire up 127.0.0.1:8001/view in your browser you will get a view served using Leaf as a templating language! ππ»
6. BONUS: Passing data to the view
Itβs super easy to pass data into a view. And this is how it looks like:
import Vaporextension Droplet {
func setupRoutes() throws { get("name") { req in
return "Ethan Hunt"
} get("age") { req in
return "\(23)"
} get("json") { req in
return try JSON(node: ["name": "Martin J. Lasek", "age": 26])
} get("view") { req in
return try self.view.make("myview")
} get("bonus") { req in
return try self.view.make("mydataview", ["name": "Taichi"])
}
}
}
If you now create a new file in Resources/Views/ called mydataview.leaf you can access the passed data in it like so:
<!DOCTYPE html>
<html>
<head>
<title>Leaf</title>
</head> <body>
<h1> You rule #(name)! </h1>
</body>
</html>
Now re-run your application and fire up 127.0.0.1:8001/bonus :D!
Thatβs it! You successfully implemented a leaf template project π !!
