URLNavigator - SwiftGit

navigation Views

URLNavigator

September 14, 2023

URLNavigator provides an elegant way to navigate through view controllers by URLs. URL patterns can be mapped by using URLNavigator.register(_:_:) function.

URLNavigator can be used for mapping URL patterns with 2 kind of types: URLNavigable and URLOpenHandler. URLNavigable is a type which defines an custom initializer and URLOpenHandler is a closure which can be executed. Both an initializer and a closure receive an URL and placeholder values.

Getting Started

1. Understanding URL Patterns

URL patterns can contain placeholders. Placeholders will be replaced with matching values from URLs. Use < and > to make placeholders. Placeholders can have types: string(default), int, float, and path.

For example, myapp://user/<int:id> matches with:

myapp://user/123
myapp://user/87

But it doesn’t match with:

myapp://user/devxoul (expected int)
myapp://user/123/posts (different url structure)
/user/devxoul (missing scheme)

2. Mapping View Controllers and URL Open Handlers

URLNavigator allows to map view controllers and URL open handlers with URL patterns. Here’s an example of mapping URL patterns with view controllers and a closure. Each closures has three parameters: url, values and context.

url is an URL that is passed from push() and present().
values is a dictionary that contains URL placeholder keys and values.
context is a dictionary which contains extra values passed from push(), present() or open().


                                              
                                                let navigator = Navigator()
// register view controllers

navigator.register(“myapp://user/<int:id>”) { url, values, context in

guard let userID = values[“id”] as? Int else { return nil }

return UserViewController(userID: userID)

}

navigator.register(“myapp://post/<title>”) { url, values, context in

return storyboard.instantiateViewController(withIdentifier: “PostViewController”)

}
// register url open handlers

navigator.handle(“myapp://alert”) { url, values, context in

let title = url.queryParameters[“title”]

let message = url.queryParameters[“message”]

presentAlertController(title: title, message: message)

return true

}

3. Pushing, Presenting and Opening URLs

URLNavigator can push and present view controllers and execute closures with URLs.

Provide the from parameter to push() to specify the navigation controller which the new view controller will be pushed. Similarly, provide the from parameter to present() to specify the view controller which the new view controller will be presented. If the nil is passed, which is a default value, current application’s top most view controller will be used to push or present view controllers.

present() takes an extra parameter: wrap. If a UINavigationController class is specified, the new view controller will be wrapped with the class. Default value is nil.


                                              
                                                Navigator.push(“myapp://user/123”)

Navigator.present(“myapp://post/54321”, wrap: UINavigationController.self)
Navigator.open(“myapp://alert?title=Hello&message=World”)

Installation

URLNavigator officially supports CocoaPods only.

Podfile


                                              
                                                pod ‘URLNavigator’

Example

You can find an example app here.

Build and install the example app.
Open Safari app
Enter navigator://user/devxoul in the URL bar.
The example app will be launched.

Tips and Tricks

Where to initialize a Navigator instance

Define as a global constant:


                                              
                                                let navigator = Navigator()
class AppDelegate: UIResponder, UIApplicationDelegate {

// …

}

2. Register to an IoC container:


                                              
                                                container.register(NavigatorProtocol.self) { _ in Navigator() } // Swinject

let navigator = container.resolve(NavigatorProtocol.self)!

3. Inject dependency from a composition root.

Where to Map URLs

I’d prefer using separated URL map file.


                                              
                                                struct URLNavigationMap {

static func initialize(navigator: NavigatorProtocol) {

navigator.register(“myapp://user/<int:id>”) { … }

navigator.register(“myapp://post/<title>”) { … }

navigator.handle(“myapp://alert”) { … }

}

}

Then call initialize() at AppDelegate‘s application:didFinishLaunchingWithOptions:.


                                              
                                                @UIApplicationMain

final class AppDelegate: UIResponder, UIApplicationDelegate {

func application(

_ application: UIApplication,

didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?

) -> Bool {

// Navigator

URLNavigationMap.initialize(navigator: navigator)
// Do something else…

}

}

Implementing AppDelegate Launch Option URL

It’s available to open your app with URLs if custom schemes are registered. In order to navigate to view controllers with URLs, you’ll have to implement application:didFinishLaunchingWithOptions: method.


                                              
                                                func application(

_ application: UIApplication,

didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?

) -> Bool {

// …

if let url = launchOptions?[.url] as? URL {

if let opened = navigator.open(url)

if !opened {

navigator.present(url)

}

}

return true

}

Implementing AppDelegate Open URL Method

You’ll might want to implement custom URL open handler. Here’s an example of using URLNavigator with other URL open handlers.


                                              
                                                func application(_ application: UIApplication, open url: URL, sourceApplication: String?, annotation: Any) -> Bool {

// If you’re using Facebook SDK

let fb = FBSDKApplicationDelegate.sharedInstance()

if fb.application(application, open: url, sourceApplication: sourceApplication, annotation: annotation) {

return true

}
// URLNavigator Handler

if navigator.open(url) {

return true

}
// URLNavigator View Controller

if navigator.present(url, wrap: UINavigationController.self) != nil {

return true

}
return false

}

Passing Extra Values when Pushing, Presenting and Opening


                                              
                                                let context: [AnyHashable: Any] = [

“fromViewController”: self

]

Navigator.push(“myapp://user/10”, context: context)

Navigator.present(“myapp://user/10”, context: context)

Navigator.open(“myapp://alert?title=Hi”, context: context)

Defining custom URL Value Converters

You can define custom URL Value Converters for URL placeholders.

For example, the placeholder <region> is only allowed for the strings ["us-west-1", "ap-northeast-2", "eu-west-3"]. If it doesn’t contain any of these, the URL pattern should not match.

Add a custom value converter to the [String: URLValueConverter] dictionary on your instance of Navigator.


                                              
                                                navigator.matcher.valueConverters[“region”] = { pathComponents, index in

let allowedRegions = [“us-west-1”, “ap-northeast-2”, “eu-west-3”]

if allowedRegions.contains(pathComponents[index]) {

return pathComponents[index]

} else {

return nil

}

}

With the code above, for example, myapp://region/<region:_> matches with: