Tips on how to make a PWA for iOS?
A progressive net software is only a particular form of web site, that may look and behave like a local iOS app. With a view to construct a PWA, first we’ll create a daily web site utilizing SwiftHtml. We will begin with a daily executable Swift bundle with the next dependencies.
import PackageDescription
let bundle = Bundle(
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 possibly can see we’ll use the vapor Vapor library to serve our HTML website. 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 facet Swift purposes, it is a fairly superb instrument I’ve a newbie’s information publish about it.
After all we’ll want some elements for rendering views utilizing SwiftHtml, you should 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. It’s best 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 principal 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 keep up a totally 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 {
Foremost {
Div {
H1(context.title)
P(context.message)
}
}
}
}
}
}Lastly we will 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 bundle by utilizing the beforehand outlined template helper strategies on the Request object.
import Vapor
import SwiftHtml
var env = attempt Atmosphere.detect()
attempt LoggingSystem.bootstrap(from: &env)
let app = Utility(env)
defer { app.shutdown() }
app.get { req -> Response in
let template = IndexTemplate(.init(title: "Whats up, World!",
message: "This web page was generated by the SwiftHtml library."))
return req.templates.renderHtml(template)
}
attempt app.run()It’s simply that straightforward to setup and bootstrap a completely 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 it is best to be capable to see a working web site by visiting the http://localhost:8080/ deal with.
Turning an internet site into an actual iOS PWA
Now if we wish to remodel our web site right into a standalone PWA, we now have to offer a hyperlink a particular net app manifest file inside the pinnacle part of the index template.
Meta tags vs manifest.json
Looks as if Apple follows form of a wierd route if it involves PWA assist. They’ve fairly a historical past of “considering exterior of the field”, this mindset applies to progressive net apps on iOS, since they do not are likely to comply with the requirements in any respect. For Android units you may create a manifest.json file with some predefined keys and you would be simply nice along with your PWA. Alternatively Apple these days prefers numerous HTML meta tags as a substitute of the online manifest format.
Personally I do not like this method, as a result of your HTML code will likely be bloated with all of the PWA associated stuff (as you will see that is going to occur if it involves launch display photos) and I consider it is higher to separate these form of issues, however hey it is Apple, they cannot be improper, proper? ?
Anyhow, let me present you the best way to assist numerous PWA options on iOS.
Enabling standalone app mode
The very first few keys that we might like so as to add to the index template has the apple-mobile-web-app-capable title and it is best to use the “sure” string as content material. This can point out that the app ought to run in full-screen mode, in any other case it’ll be displayed utilizing Safari identical to a daily website.
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 {
Foremost {
Div {
H1(context.title)
P(context.message)
}
}
}
}
}
}We should always change the hostname of the server and hear on the 0.0.0.0 deal with, this fashion in case your telephone is on the identical native WiFi community it is best to be capable to attain your net server immediately.
import Vapor
import SwiftHtml
var env = attempt Atmosphere.detect()
attempt LoggingSystem.bootstrap(from: &env)
let app = Utility(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: "Whats up, World!",
message: "This web page was generated by the SwiftHtml library."))
return req.templates.renderHtml(template)
}
attempt app.run()Yow will discover out your native IP deal with by typing the next command into the Terminal app.
# utilizing ifconfig & grep
ifconfig | grep -Eo 'inet (addr:)?([0-9]*.){3}[0-9]*' | grep -Eo '([0-9]*.){3}[0-9]*' | grep -v '127.0.0.1'
# utilizing ifconfig & sed
ifconfig | sed -En 's/127.0.0.1//;s/.*inet (addr:)?(([0-9]*.){3}[0-9]*).*/2/p'
Simply use that IP deal with and go to the http://[ip-address]:8080/ web site utilizing your iOS gadget, then it is best to be capable to add your web site to your private home display as a bookmark. Simply faucet the Share icon utilizing Safari and choose the Add to House Display menu merchandise from the listing. On the brand new display faucet the Add button on the highest proper nook, it will create a brand new icon on your private home display as a bookmark to your web page. Optionally, you possibly can present a customized title for the bookmark. ??
Since we have added the meta tag, when 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 supply 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 sort that a lot. The icon state of affairs is a little more tough, since we now have so as to add a bunch of dimension 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("Whats up PWA")
Hyperlink(rel: .appleTouchIcon)
.href("/img/apple/icons/192.png")
for dimension in [57, 72, 76, 114, 120, 144, 152, 180] {
Hyperlink(rel: .appleTouchIcon)
.sizes("(dimension)x(dimension)")
.href("/img/apple/icons/(dimension).png")
}
}
Physique {
Foremost {
Div {
H1(context.title)
P(context.message)
}
}
}
}
}
}As you possibly can see icons are referenced by utilizing the Hyperlink tag, utilizing the Apple contact icon rel attribute. The default icon with out the sizes attribute is usually 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 = attempt Atmosphere.detect()
attempt LoggingSystem.bootstrap(from: &env)
let app = Utility(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: "Whats up, World!",
message: "This web page was generated by the SwiftHtml library."))
return req.templates.renderHtml(template)
}
attempt 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 at liberty 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 will be nice, however in case you are utilizing Xcode you must specify a customized working listing for Vapor, it will enable the system to search for the general public information from the best place.
Your customized icons will not present up in case you are utilizing a self-signed certificates.
Construct and run the server and attempt to bookmark your web page once more utilizing your telephone. While you see the add bookmark web page it is best to be capable to validate that the app now makes use of the predefined Whats up PWA title and the picture preview ought to present the customized icon file as a substitute 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 latest model of Safari and the way it handles numerous theme colours on completely different platforms. It is an amazing article, it is best to positively learn it, however in many of the circumstances you will not want this a lot information, however you merely wish to assist gentle and darkish mode on your progressive net app. That is what I will 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 fashion.css file so we will change the background of the positioning and the font colour in response to the present colour scheme. First, the brand new meta tags to assist 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("Whats up 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/fashion.css")
Hyperlink(rel: .appleTouchIcon)
.href("/img/apple/icons/192.png")
for dimension in [57, 72, 76, 114, 120, 144, 152, 180] {
Hyperlink(rel: .appleTouchIcon)
.sizes("(dimension)x(dimension)")
.href("/img/apple/icons/(dimension).png")
}
}
Physique {
Foremost {
Div {
H1(context.title)
P(context.message)
}
}
}
}
}
}Contained in the fashion CSS file we will use a media question to detect the popular colour scheme, identical 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 principal background. Attempt to change between darkish and lightweight mode and ensure every little thing works, there’s a cool PWA demo challenge right here with completely different colours for every mode if you wish to double verify the code. ?
Splash display assist
Trace: it is ridiculous. Splash screens on iOS are problematic. Even native apps are likely to cache the improper splash display or will not render PNG information correctly, now if it involves PWAs this is not needed higher. I used to be capable of present splash display photos for my app, nevertheless it took me fairly some time and switching between darkish and lightweight mode is completely damaged (so far as I do know it). ?
With a view to cowl each single gadget display dimension, you must add numerous linked splash photos 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)
change orientation {
case .portrait:
return w + "x" + h
case .panorama:
return h + "x" + w
}
}
}Now I can merely add the splashTags() name into the pinnacle part, however I am unsure if the result’s one thing I can completely agree with. Right here, check out the tip of this tutorial about splash screens, the code required to assist iOS splash screens could be very lengthy and I have never even informed you concerning the 40 completely different picture information that you’re going to want. Individuals are actually utilizing PWA asset mills to cut back the time wanted to generate these form of photos, as a result of it is fairly uncontrolled. ?
Protected space & the notch
A particular subject I might like to speak about is the secure space assist 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 will use 4 environmental variables in CSS to set correct margin and padding values.
First we now have to vary the viewport meta tag and lengthen our web page past the secure space. This may be completed 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 can 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("Whats up 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/fashion.css")
Hyperlink(rel: .appleTouchIcon)
.href("/img/apple/icons/192.png")
for dimension in [57, 72, 76, 114, 120, 144, 152, 180] {
Hyperlink(rel: .appleTouchIcon)
.sizes("(dimension)x(dimension)")
.href("/img/apple/icons/(dimension).png")
}
splashTags()
}
Physique {
Header {
Div {
P("Header space")
}
.class("safe-area")
}
Foremost {
Div {
Div {
H1(context.title)
for _ in 0...42 {
P(context.message)
}
A("Refresh web page")
.href("/")
}
.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 move exterior the secure space, so we will outline a brand new CSS class and place some margins on it based mostly on the surroundings. Additionally we can safely use the calc CSS perform if we wish to add some further worth to the surroundings.
* {
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 seems to be 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 verify if the app runs in a standalone mode you will should create an internet manifest.json file with the next contents.
{
"show": "standalone"
}
Subsequent you must 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 should use the display-mode selector to verify if the app is operating in a standalone mode, you possibly can 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 strong #eee;
}
}
@media (display-mode: standalone) and (prefers-color-scheme: darkish) {
header, footer {
background: #000;
}
header {
border-bottom: 1px strong #333;
}
}
You’ll be able to flip the header right into a sticky part by utilizing the place: sticky attribute. I often favor to comply with the iOS fashion when the web site is introduced to the end-user as a standalone app and I preserve the unique theme colours for the online solely.
Do not forget 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. ??
As you possibly can see constructing handsome progressive net apps for iOS is kind of tough, particularly if it involves the metadata insanity that Apple created. Anyway, I hope this tutorial will aid you to construct higher PWAs for the iOS platform. That is simply the tip of the iceberg, we have not talked about JavaScript in any respect, however perhaps I am going to come again with that subject in a brand new tutorial afterward.