Maxim Salnikov
@webmaxru
Building and deploying a
My App
Mobile platform
2,5B advantages
-
At least two development teams required
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Existing solutions for cross-platform development are a kind of trade-off
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App stores started to ban the applications built with templates and constructors
Native apps
}
Expensive to develop
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About 60% of the applications were never installed (Google Play)
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65.5% of the users install 0 (zero) applications per month (USA)
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Less than 1% of participants share more than 94% of the revenue on this market (USA, AppStore)
App stores
}
Expensive to acquire new users
What if we try web tech?
Chris Anderson, Wired, 2010
As much as we love the open, unfettered Web, we're abandoning it for simpler, sleeker services [native apps] that just work
The biggest mistake we’ve made as a company is betting on HTML5 over native.
Mark Zuckerberg, 2012
Today's web
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Constantly improving performance of JavaScript engines
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Access to devices hardware
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APIs for authentication & payments
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Deep integration with operating systems
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Going beyond online and out of the browsers
}
The state of the web
whatwebcando.today
What is PWA at all?
Progressive web apps use modern web APIs along with traditional progressive enhancement strategy to create cross-platform web applications.
These apps work everywhere and provide several features that give them the same user experience advantages as native apps.
UX advantages?
Smart networking + Offline
Proper app experience
Staying notified
Other cool things
}
Service Worker API
Web App Manifest
works everywhere*
* but not everything**
natively
** use progressive enhancement strategy
Platforms / browsers support
APIs actively used in PWAs
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Service Worker API
-
Cache API
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IndexedDB
-
Fetch
-
Clients API
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Broadcast Channel API
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Push API
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Notifications API
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Local Storage
-
Session Storage
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XMLHttpRequest
-
DOM
Not available in service worker:
Even more capable web
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Writable Files API
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WebHID API
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Scheduled Task / Notification API
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Web Share Target API
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Wake Lock API
-
Cookie Store API
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User Idle Detection API
-
...
Project Fugu
Minimum viable PWA
=
+
Application shell
Web App Manifest
Fast, responsive, mobile-first
Served via HTTPS
Let's build an App Shell
My App
-
Define the set of assets required to show the minimum viable UI
Service worker
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install: put the assets into Cache Storage
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activate: clear Cache Storage from the previous app version assets
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fetch: if the asset is in Cache Storage serve it from there. Otherwise — download and serve it (and cache it)
Build time
-
Register service worker the way it does not affect the app loading performance
Website/webapp
Service Worker
Service Worker 101
Logically
Physically
-file(s)
App
Service-worker
Browser/OS
Event-driven worker
Cache
fetch
push
sync
Lifecycle
'install'
Parsed
Installing
Activating
Redundant
'activate'
Waiting
Active
Managing cache
self.addEventListener('install', (event) => {
// Put app's html/js/css to cache
})self.addEventListener('activate', (event) => {
// Wipe previous version of app files from cache
})In the real world
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Can't add opaque responses directly
-
Redirected requests should be managed
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Always creating a new version of cache and deleting the old one is not optimal
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Control over cache size is required
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Cache invalidation for runtime caching is complex
-
...
Intercepting requests
self.addEventListener('fetch', (event) => {
if (event.request.url.indexOf('/api') != -1) {
event.respondWith(
// Network-First Strategy
)
} else {
event.respondWith(
// Cache-First Strategy
)
}
})In the real world
-
All kinds of fallbacks needed for the strategies
-
There are more complex strategies like Stale-While-Revalidate
-
Good to have routing
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Good to have the possibility to provide some extra settings for different resource groups
-
...
Tools & libraries
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Implementing complex algorithms
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Adopting best practices
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Focusing on YOUR task
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Following specifications updates
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Handling edge cases
Tools help with
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Application shell
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Runtime caching
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Replaying failed network requests
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Offline Google Analytics
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Broadcasting updates
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Registration helper
Have our own service worker!
Demo time
Thank you!
Maxim Salnikov
@webmaxru
Questions?
Maxim Salnikov
@webmaxru