Progressive Internet Apps on iOS

make a PWA for iOS?

A progressive net software is only a particular type of web site, that may look and behave like a local iOS app. So as to construct a PWA, first we’ll create an everyday web site utilizing SwiftHtml. We are able to begin with an everyday executable Swift package deal with the next dependencies.

import PackageDescription

let package deal = Package deal(
    title: "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(title: "ExampleTests", dependencies: ["Example"]),
    ]
)

As you may see we’ll use the vapor Vapor library to serve our HTML web site. If you do not know a lot about Vapor let’s simply say that it’s a net software framework, which can be utilized to construct server aspect Swift functions, it is a fairly wonderful instrument I’ve a newbie’s information put up about it.

After all we’ll want some parts for rendering views utilizing SwiftHtml, you need to use the supply snippets from my earlier article, however right here it’s once more how the SwiftHtml-based template engine ought to seem like. You need to learn my different article if you wish to know extra about it. 🤓

import Vapor
import SwiftSgml

public protocol TemplateRepresentable {
    
    @TagBuilder
    func render(_ req: Request) -> Tag
}

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))
    }
}

public extension Request {
    var templates: TemplateRenderer { .init(self) }
}

We’re additionally going to wish an index template for our fundamental HTML doc. Since we’re utilizing a Swift DSL to jot down HTML code we do not have to fret an excessive amount of about mistyping a tag, the compiler will defend us and helps to take care of a very legitimate HTML construction.

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().title(.viewport).content material("width=device-width, initial-scale=1")
            }
            Physique {
                Predominant {
                    Div {
                        H1(context.title)
                        P(context.message)
                    }
                }
            }
        }
    }
}

Lastly we are able to merely render the bootstrap our Vapor server occasion, register our route handler and render the index template inside the primary entry level of our Swift package deal by utilizing the beforehand outlined template helper strategies on the Request object.

import Vapor
import SwiftHtml

var env = strive Atmosphere.detect()
strive LoggingSystem.bootstrap(from: &env)
let app = Software(env)
defer { app.shutdown() }

app.get { req -> Response in
    let template = IndexTemplate(.init(title: "Good day, World!",
                                    message: "This web page was generated by the SwiftHtml library."))
    
    return req.templates.renderHtml(template)
}

strive app.run()

It’s simply that simple to setup and bootstrap a totally working net server that’s able to rendering a HTML doc utilizing the facility of Swift and the Vapor framework. For those who run the app you must be capable of see a working web site by visiting the http://localhost:8080/ handle.

Turning an internet site into an actual iOS PWA

Now if we need to remodel our web site right into a standalone PWA, we now have to supply a hyperlink a particular net app manifest file inside the top part of the index template.

Meta tags vs manifest.json

Looks like Apple follows type of an odd route if it involves PWA help. They’ve fairly a historical past of “considering outdoors of the field”, this mindset applies to progressive net apps on iOS, since they do not are likely to observe the requirements in any respect. For Android units you possibly can create a manifest.json file with some predefined keys and you would be simply wonderful along with your PWA. However Apple these days prefers varied HTML meta tags as an alternative of the online manifest format.

Personally I do not like this method, as a result of your HTML code can be bloated with all of the PWA associated stuff (as you may see that is going to occur if it involves launch display pictures) and I consider it is higher to separate these type of issues, however hey it is Apple, they cannot be fallacious, proper? 😅

In any case, let me present you how you can help varied PWA options on iOS.

Enabling standalone app mode

The very first few keys that we would like so as to add to the index template has the apple-mobile-web-app-capable title and you must use the “sure” string as content material. It will point out that the app ought to run in full-screen mode, in any other case it may be displayed utilizing Safari similar to an everyday web site.

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().title(.viewport).content material("width=device-width, initial-scale=1")

                Meta()
                    .title(.appleMobileWebAppCapable)
                    .content material("sure")
            }
            Physique {
                Predominant {
                    Div {
                        H1(context.title)
                        P(context.message)
                    }
                }
            }
        }
    }
}

We must always change the hostname of the server and pay attention on the 0.0.0.0 handle, this fashion in case your telephone is on the identical native WiFi community you must be capable of attain your net server instantly.

import Vapor
import SwiftHtml

var env = strive Atmosphere.detect()
strive LoggingSystem.bootstrap(from: &env)
let app = Software(env)
defer { app.shutdown() }

app.http.server.configuration.hostname = "0.0.0.0"
if let hostname = Atmosphere.get("SERVER_HOSTNAME") {
    app.http.server.configuration.hostname = hostname
}

app.get { req -> Response in
    let template = IndexTemplate(.init(title: "Good day, World!",
                                    message: "This web page was generated by the SwiftHtml library."))
    
    return req.templates.renderHtml(template)
}

strive app.run()

You could find out your native IP handle by typing the next command into the Terminal app.

ifconfig | grep -Eo 'inet (addr:)?([0-9]*.){3}[0-9]*' | grep -Eo '([0-9]*.){3}[0-9]*' | grep -v '127.0.0.1'

ifconfig | sed -En 's/127.0.0.1//;s/.*inet (addr:)?(([0-9]*.){3}[0-9]*).*/2/p'

Simply use that IP handle and go to the http://[ip-address]:8080/ web site utilizing your iOS gadget, then you must be capable of add your web site to your property display as a bookmark. Simply faucet the Share icon utilizing Safari and choose the Add to Dwelling Display menu merchandise from the checklist. On the brand new display faucet the Add button on the highest proper nook, this may create a brand new icon on your property display as a bookmark to your web page. Optionally, you may present a customized title for the bookmark. ☺️

Since we have added the meta tag, in the event you contact the newly created icon it ought to open the webpage as a standalone app (with out utilizing the browser). After all the app remains to be only a web site rendered utilizing an internet view. The standing bar will not match the white background and it has no customized icon or splash display but, however we’ll repair these points proper now. 📱

Customized title and icon

To offer a customized title we simply have so as to add a brand new meta tag, luckily the SwiftHtml library has predefined enums for all of the Apple associated meta names, so you do not have to kind that a lot. The icon state of affairs is a little more troublesome, since we now have so as to add a bunch of measurement variants.

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().title(.viewport).content material("width=device-width, initial-scale=1")
                
                Meta()
                    .title(.appleMobileWebAppCapable)
                    .content material("sure")
                
                Meta()
                    .title(.appleMobileWebAppTitle)
                    .content material("Good day PWA")
                
                Hyperlink(rel: .appleTouchIcon)
                    .href("/img/apple/icons/192.png")

                for measurement in [57, 72, 76, 114, 120, 144, 152, 180] {
                    Hyperlink(rel: .appleTouchIcon)
                        .sizes("(measurement)x(measurement)")
                        .href("/img/apple/icons/(measurement).png")
                }
            }
            Physique {
                Predominant {
                    Div {
                        H1(context.title)
                        P(context.message)
                    }
                }
            }
        }
    }
}

As you may see icons are referenced by utilizing the Hyperlink tag, utilizing the Apple contact icon rel attribute. The default icon with out the sizes attribute could be a 192×192 pixel picture, plus I am offering some smaller sizes by utilizing a for loop right here. We additionally must serve these icon information by utilizing Vapor, that is why we’ll alter the configuration file and allow the FileFiddleware.

import Vapor
import SwiftHtml

var env = strive Atmosphere.detect()
strive LoggingSystem.bootstrap(from: &env)
let app = Software(env)
defer { app.shutdown() }

app.middleware.use(FileMiddleware(publicDirectory: app.listing.publicDirectory))

app.http.server.configuration.hostname = "0.0.0.0"
if let hostname = Atmosphere.get("SERVER_HOSTNAME") {
    app.http.server.configuration.hostname = hostname
}

app.get { req -> Response in
    let template = IndexTemplate(.init(title: "Good day, World!",
                                    message: "This web page was generated by the SwiftHtml library."))
    
    return req.templates.renderHtml(template)
}

strive app.run()

By including the FileMiddleware to the app with the general public listing path configuration your server app is ready to serve static information from the Public listing. Be happy to create it and place the app icons beneath the Public/img/apple/icons folder. If you’re operating the server from the command line you may be wonderful, however if you’re utilizing Xcode it’s a must to specify a customized working listing for Vapor, this may permit the system to search for the general public information from the precise place.

Construct and run the server and attempt to bookmark your web page once more utilizing your telephone. Whenever you see the add bookmark web page you must be capable of validate that the app now makes use of the predefined Good day PWA title and the picture preview ought to present the customized icon file as an alternative of a screenshot of the web page.

Correct standing bar colour for iOS PWAs

Lengthy story quick, there’s a nice article on CSS-Methods about the newest model of Safari and the way it handles varied theme colours on completely different platforms. It is an ideal article, you must positively learn it, however in many of the circumstances you will not want this a lot data, however you merely need to help gentle and darkish mode to your progressive net app. That is what I’ll present you right here.

For gentle mode we’ll use a white background colour and for darkish mode we use black. We’re additionally going to hyperlink a brand new model.css file so we are able to change the background of the location and the font colour based on the present colour scheme. First, the brand new meta tags to help theme colours each for gentle and darkish mode.

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().title(.viewport).content material("width=device-width, initial-scale=1")
                
                Meta()
                    .title(.appleMobileWebAppCapable)
                    .content material("sure")
                Meta()
                    .title(.appleMobileWebAppTitle)
                    .content material("Good day PWA")
                
                Meta()
                    .title(.colorScheme)
                    .content material("gentle darkish")
                Meta()
                    .title(.themeColor)
                    .content material("#fff")
                    .media(.prefersColorScheme(.gentle))
                Meta()
                    .title(.themeColor)
                    .content material("#000")
                    .media(.prefersColorScheme(.darkish))
                
                Hyperlink(rel: .stylesheet)
                    .href("/css/model.css")
                
                Hyperlink(rel: .appleTouchIcon)
                    .href("/img/apple/icons/192.png")
                for measurement in [57, 72, 76, 114, 120, 144, 152, 180] {
                    Hyperlink(rel: .appleTouchIcon)
                        .sizes("(measurement)x(measurement)")
                        .href("/img/apple/icons/(measurement).png")
                }
            }
            Physique {
                Predominant {
                    Div {
                        H1(context.title)
                        P(context.message)
                    }
                }
            }
        }
    }
}

Contained in the model CSS file we are able to use a media question to detect the popular colour scheme, similar to we did it for the .themeColor meta tag utilizing SwiftHtml.

physique {
    background: #fff;
    colour: #000;
}
@media (prefers-color-scheme: darkish) {
    physique {
        background: #000;
        colour: #fff;
    }
}

That is it, now the standing bar ought to use the identical colour as your fundamental background. Attempt to swap between darkish and light-weight mode and ensure all the pieces works, there’s a cool PWA demo venture right here with completely different colours for every mode if you wish to double test the code. ✅

Splash display help

Trace: it is ridiculous. Splash screens on iOS are problematic. Even native apps are likely to cache the fallacious splash display or will not render PNG information correctly, now if it involves PWAs this is not crucial higher. I used to be in a position to present splash display pictures for my app, but it surely took me fairly some time and switching between darkish and light-weight mode is completely damaged (so far as I do know it). 😅

So as to cowl each single gadget display measurement, it’s a must to add a lot of linked splash pictures to your markup. It is so ugly I even needed to create a bunch of extension strategies to my index template.

extension IndexTemplate {
    
    @TagBuilder
    func splashTags() -> [Tag] {
        splash(320, 568, 2, .panorama)
        splash(320, 568, 2, .portrait)
        splash(414, 896, 3, .panorama)
        splash(414, 896, 2, .panorama)
        splash(375, 812, 3, .portrait)
        splash(414, 896, 2, .portrait)
        splash(375, 812, 3, .panorama)
        splash(414, 736, 3, .portrait)
        splash(414, 736, 3, .panorama)
        splash(375, 667, 2, .panorama)
        splash(375, 667, 2, .portrait)
        splash(1024, 1366, 2, .panorama)
        splash(1024, 1366, 2, .portrait)
        splash(834, 1194, 2, .panorama)
        splash(834, 1194, 2, .portrait)
        splash(834, 1112, 2, .panorama)
        splash(414, 896, 3, .portrait)
        splash(834, 1112, 2, .portrait)
        splash(768, 1024, 2, .portrait)
        splash(768, 1024, 2, .panorama)
    }
    
    @TagBuilder
    func splash(_ width: Int,
                _ top: Int,
                _ ratio: Int,
                _ orientation: MediaQuery.Orientation) -> Tag {
        splashTag(.gentle, width, top, ratio, orientation)
        splashTag(.darkish, width, top, ratio, orientation)
    }
        
    func splashTag(_ mode: MediaQuery.ColorScheme,
                   _ width: Int,
                   _ top: Int,
                   _ ratio: Int,
                   _ orientation: MediaQuery.Orientation) -> Tag {
        Hyperlink(rel: .appleTouchStartupImage)
            .media([
                .prefersColorScheme(mode),
                .deviceWidth(px: width),
                .deviceHeight(px: height),
                .webkitDevicePixelRatio(ratio),
                .orientation(orientation),
            ])
            .href("/img/apple/splash/(calc(width, top, ratio, orientation))(mode == .gentle ? "" : "_dark").png")
    }
    
    func calc(_ width: Int,
              _ top: Int,
              _ ratio: Int,
              _ orientation: MediaQuery.Orientation) -> String {
        let w = String(width * ratio)
        let h = String(top * ratio)
        swap orientation {
        case .portrait:
            return w + "x" + h
        case .panorama:
            return h + "x" + w
        }
    }
}

Now I can merely add the splashTags() name into the top part, however I am undecided if the result’s one thing I can completely agree with. Right here, check out the top of this tutorial about splash screens, the code required to help iOS splash screens could be very lengthy and I have never even informed you concerning the 40 completely different picture information that you will want. Persons are actually utilizing PWA asset mills to scale back the time wanted to generate these type of photos, as a result of it is fairly uncontrolled. 💩

I am utilizing this system in Feather CMS, so if you would like to obtain some pattern information you may seize them from GitHub. I am not pleased with splash display help, however hey, it simply works, proper? 🤔

Secure space & the notch

A particular subject I would like to speak about is the secure space help and the notch. I can extremely advocate to learn this text on CSS-Methods about The Notch and CSS first, however the primary trick is that we are able to use 4 environmental variables in CSS to set correct margin and padding values.

First we now have to alter the viewport meta tag and prolong our web page past the secure space. This may be performed by utilizing the viewport-fit cowl worth. Contained in the physique of the template we’ll add a header and a footer part, these areas may have customized background colours and fill the display.

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()
                    .title(.viewport)
                    .content material("width=device-width, initial-scale=1, viewport-fit=cowl")
                    
                
                Meta()
                    .title(.appleMobileWebAppCapable)
                    .content material("sure")
                Meta()
                    .title(.appleMobileWebAppTitle)
                    .content material("Good day PWA")
                
                Meta()
                    .title(.colorScheme)
                    .content material("gentle darkish")
                Meta()
                    .title(.themeColor)
                    .content material("#fff")
                    .media(.prefersColorScheme(.gentle))
                Meta()
                    .title(.themeColor)
                    .content material("#000")
                    .media(.prefersColorScheme(.darkish))
                
                Hyperlink(rel: .stylesheet)
                    .href("/css/model.css")
                
                Hyperlink(rel: .appleTouchIcon)
                    .href("/img/apple/icons/192.png")
                for measurement in [57, 72, 76, 114, 120, 144, 152, 180] {
                    Hyperlink(rel: .appleTouchIcon)
                        .sizes("(measurement)x(measurement)")
                        .href("/img/apple/icons/(measurement).png")
                }
                
                splashTags()
            }
            Physique {
                Header {
                    Div {
                        P("Header space")
                    }
                    .class("safe-area")
                }
                
                Predominant {
                    Div {
                        Div {
                            H1(context.title)
                            for _ in 0...42 {
                                P(context.message)
                            }
                            A("Refresh web page")
                                .href("https://theswiftdev.com/")
                        }
                        .class("wrapper")
                    }
                    .class("safe-area")
                }

                Footer {
                    Div {
                        P("Footer space")
                    }
                    .class("safe-area")
                }
            }
        }
    }
}

Besides the background colour we do not need different content material to movement outdoors the secure space, so we are able to outline a brand new CSS class and place some margins on it based mostly on the setting. Additionally we can safely use the calc CSS operate if we need to add some additional worth to the setting.

* {
    margin: 0;
    padding: 0;
}
physique {
    background: #fff;
    colour: #000;
}
header, footer {
    padding: 1rem;
}
header {
    background: #eee;
}
footer {
    background: #eee;
    padding-bottom: calc(1rem + env(safe-area-inset-bottom));
}
.safe-area {
    margin: 0 env(safe-area-inset-right) 0 env(safe-area-inset-left);
}
.wrapper {
    padding: 1rem;
}
@media (prefers-color-scheme: darkish) {
    physique {
        background: #000;
        colour: #fff;
    }
    header {
        background: #222;
    }
    footer {
        background: #222;
    }
}

It appears good, however what if we would like to make use of customized kinds for the PWA model solely?

Detecting standalone mode

If you wish to use the show mode media question in your CSS file we now have so as to add a manifest file to our PWA. Yep, that is proper, I’ve talked about earlier than that Apple prefers to make use of meta tags and hyperlinks, however if you wish to use a CSS media question to test if the app runs in a standalone mode you may must create an internet manifest.json file with the next contents.

{
  "show": "standalone"
}

Subsequent it’s a must to present a hyperlink to the manifest file contained in the template file.

struct IndexTemplate: TemplateRepresentable {
    
    
    
    func render(_ req: Request) -> Tag {
        Html {
            Head {
                
                
                splashTags()
                
                Hyperlink(rel: .manifest)
                    .href("/manifest.json")
            }
            Physique {
                
            }
        }
    }
}

Within the CSS file now you need to use the display-mode selector to test if the app is operating in a standalone mode, you may even mix these selectors and detect standalone mode and darkish mode utilizing a single question. Media queries are fairly helpful. 😍

/* ... */

@media (display-mode: standalone) {
    header, footer {
        background: #fff;
    }
    header {
        place: sticky;
        prime: 0;
        border-bottom: 1px stable #eee;
    }
}
@media (display-mode: standalone) and (prefers-color-scheme: darkish) {
    header, footer {
        background: #000;
    }
    header {
        border-bottom: 1px stable #333;
    }
}

You may flip the header right into a sticky part by utilizing the place: sticky attribute. I normally want to observe the iOS model when the web site is offered to the end-user as a standalone app and I maintain the unique theme colours for the online solely.

Remember to rebuild the backend server, earlier than you check your app. Since we have made some meta modifications you might need to delete the PWA bookmark and set up it once more to make issues work. ⚠️