投稿時間:2022-12-26 10:21:55 RSSフィード2022-12-26 10:00 分まとめ(25件)

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IT	ITmedia 総合記事一覧	[ITmedia ビジネスオンライン] 94％の大学生が就職内定　最多の業種は？	https://www.itmedia.co.jp/business/articles/2212/26/news037.html	itmedia	2022-12-26 09:30:00
デザイン	コリス	今年最後のKindleセールが開催！ デザインやイラスト関連の良書がたくさん、SBクリエイティブ 50％オフセールが超お買い得	https://coliss.com/articles/products/kindle-sales-202212-sb-creative.html	続きを読む	2022-12-26 00:36:16
js	JavaScriptタグが付けられた新着投稿 - Qiita	配列の要素の追加、削除のまとめ(JavaScript)	https://qiita.com/nogizakapython/items/54007c860dc18707575a	scoresun	2022-12-26 09:50:20
Ruby	Rubyタグが付けられた新着投稿 - Qiita	サンプルコードでわかる！Ruby 3.2の主な新機能と変更点	https://qiita.com/jnchito/items/bdee57b45f12a0d5eeae	毎年	2022-12-26 09:03:19
AWS	AWSタグが付けられた新着投稿 - Qiita	CJ Moses’ Security Predictions for 2023 and Beyondを斜め読みしながら、来年のAWSセキュリティを考えてみた	https://qiita.com/pict3/items/cc97baf159905c2aa697	ebook	2022-12-26 09:23:10
技術ブログ	Developers.IO	AWS Lambda PythonでSeleniumを使える環境を構築する	https://dev.classmethod.jp/articles/aws-lambda-python-selenium-make-env/	awslambdapython	2022-12-26 00:00:53
海外TECH	DEV Community	Service workers tutorial	https://dev.to/uploadcare/service-workers-tutorial-1b7h	Service workers tutorialWeb developers or anyone involved in web development can tell you they know of “workers in browsers However the problem is that most folks think of either web workers in general or service workers or even shared workers when they say “workers These terms can be confusing especially if you didn t come across them That is why today we will dive into service workers We ll see why you d want to use service workers what they are how they work and explain the difference between service workers and other workers in the browser Before we start let s dive in and see what the web workers are in general What are web workers A web worker is a background task defined via script ーa JavaScript file Web workers can communicate back and forth with their creator A web worker runs in a separate thread from the main JavaScript thread To see how they work and get a small introduction to the world of web workers let us go through a simple example You can create a web worker in the application code like so const myAwesomeWorker new Worker path to worker js Then you can communicate with the worker myAwesomeWorker postMessage Hi there love you Inside the web worker you can accept the message and respond back to the caller path to worker jsonmessage function e do some magic here postMessage I am all done back to you main application code Then the caller can listen to the messages from the web worker myAwesomeWorker onmessage function e console log Message received from myAwesomeWorker console log e data Above is a trivial example of how web workers work but it should be a great start to our topic where we will explore a specialized worker ーservice worker To summarize a web worker is a JavaScript file that runs in a different thread but still can communicate with our application code We can communicate with the web worker back and forth and it can be a great helper when we want to delegate work away from the main thread of our application Now that we got over the basics let s see what service workers are What are service workers A service worker is a mediator between the web application the browser and the network The service worker is like a proxy server that sits between your application and the network intercepting requests and serving the corresponding responses You can also envision a service worker as a middleware for your site Any request from the site and any response it gets goes through the service worker Besides being a middleware service workers also have access to a cache where they can save responses and assets All this makes a perfect scenario if you re planning to add exceptional offline support to your website A service worker can decide if it should serve a resource from the cache or the network as it would happen without a service worker However it is important to note that not all browsers support service workers We should make service workers an enhancement rather than a requirement for our website One more use case can be the ability to use Push API to receive notifications from the server This API provides the option for developers to deliver asynchronous messages and updates to users who opt in resulting in better engagement with timely new content For example you can build a service worker that will update users when a new app is available OK now that we understand the concept of service workers let s see what a typical lifecycle of a service worker is The service worker lifecycleTo fully understand how service workers behave we must understand the different states they can exist in To use a service worker we have to register it on the client side Here s how we can do it if serviceWorker in navigator navigator serviceWorker register myServiceWorker js First we do a simple check to see if service workers are supported in the user s browser Then we call navigator serviceWorker register with the path to our service worker JavaScript file Then we have to distinguish two use cases When we register a service worker for the first timeWhen we update the existing service worker Registering a service worker for the first timeIn the first scenario where the page doesn t have any service workers the client will attempt to download the service worker we registered After the download the browser will try to install the service worker After successful installation the service worker is then activated and ready to perform To sum up the first case the lifecycle looks like this Download parse and execute InstallActivate Updating existing service workerNow in the second use case where we want to update the existing service worker we might get into an extra state between installing and activating If an existing service worker is available the installation for the new worker is done in the background Once the installation is complete the new worker is not yet activated The worker now needs to wait for when there are no longer any pages loaded that are still using the old service worker As soon as there are no more pages to be loaded the new service worker activates becoming the active worker You can skip the waiting for the new worker using ServiceWorkerGlobalScope skipWaiting So when the service worker is updated this is how its lifecycle looks DownloadInstallWaitActivateWe talked about how to register a service worker and how browsers later activate it But how does the lifespan of a service worker end It s important to note that service workers don t live indefinitely While exact timings differ between browsers service workers will be terminated if they ve been idle for a few seconds or if they ve been busy for too long If a service worker has been terminated and an event occurs that may start it up it will be restarted All in all the service worker lifecycle can be shown in one diagram OK now that we got through the basics on how to register a service worker and its whole lifecycle in the browser let s go on and see how it works We re going to create a service worker that caches our requests Using service worker to cache requestsOne of the most common use cases for service workers is that they are used to cache assets and requests on your website They are a fundamental part if you re looking into making a Progressive Web App PWA As we mentioned before when registered the service worker acts as a layer between your website and the network The worker intercepts every request from your website out to the world In addition to being a middleware between your website and the world a service worker can utilize the Cache Storage API In this example we will use just that ーa simple service worker that caches requests in the browser s cache This API works similarly to the browser s standard cache but it is specific to your domain You have full control over the API meaning you can control when the keys expire and add new keys It s important to mention that the service worker s storage is independent of the browser HTTP cache to ensure we don t mix the two Without further ado let us go into how we can cache our resources with service workers Caching assets on service worker s installationBefore our service worker is fired we need to register it on a page We will use a similar code we used in the lifecycle section const registerWorker async gt if serviceWorker in navigator try const registration await navigator serviceWorker register worker js console log Service worker registration succeeded registration catch error console error Registration failed with error registerWorker First we will check whether service workers are supported in the context where our code runs with serviceWorker in navigator check After that we ll do navigator serviceWorker register worker js which will register the worker js file as our service worker After that we ll write to the browser console to ensure everything gets set up correctly If there were an error somewhere our try catch block would take care of that Also it is good to note that every service worker has a configurable scope You can set scope when registering a script to be a service worker like so navigator serviceWorker register worker js scope some scope If you omit scope it will use the default value The default value of the scope depends on where the service worker got registered If you register a service worker under domain com index html the worker will control domain com index html and all pages underneath If you change the scope to something else like below navigator serviceWorker register worker js scope blog And if you register the service worker in the domain com index html then it will control only the domain com blog portion of it Great now that we registered our service worker and understand the concept of a worker s scope ーlet us define some logic in the service worker file worker js Here s how it will look const version v const addResourcesToCache async resources gt const cache await caches open version await cache addAll resources self addEventListener install event gt console log version installing event waitUntil addResourcesToCache index html styles css script js jungle png At the top we first declare the version to be v ーwe ll get to this in a second Then we define the addResourcesToCache function that opens a Cache Storage instance and writes to it with const cache await caches open version await cache addAll resources The caches open receives a string that represents a cache name Later on as we change our service worker we will have to change the name of the cache and remove the old one but we ll get to that in a second So if we open our page now the service worker defined in worker js will install and cache our resources To be sure it happened we can check the “Applications tab in Google Chrome If we open the “Storage section there we will see how much storage our website is taking Also we can go into “Cache Storage and check the v cache we just created in our service worker In “Cache Storage you should see the resources we specified Cool we got our website s assets in the service worker cache safely away from the standard browser cache But what now you must be asking Now we need to tell the browser to serve those assets from the cache And a great way to do that is to use our service worker Serving assets from the cacheWe will listen for a fetch event in our worker and intercept requests going from our website to the network Here s how it looks self addEventListener fetch event gt event respondWith caches match event request With this code we are hijacking each request firing from our site Then we call respondWith and respond with a cached value in our cache If we add this code close and then reopen our website and open the “Network tab in a browser We will see that the resources are cached in by the service worker This is all fine and dandy but if we add a resource to our site or remove a resource from the cache manually our site can break For example I tried to remove styles css from the cache in “Application →“Cache Storage and the CSS went missing the next time I opened the page Neither worker nor the browser fetched styles css again because of the logic in the worker To mitigate this we have to make sure that a request gets passed through our service worker if there s no matching resource in our cache Here s how we can do that const cacheFirst async request gt const responseFromCache await caches match request if responseFromCache return responseFromCache return fetch request self addEventListener fetch event gt event respondWith cacheFirst event request With the new cacheFirst function we are sure that a request that is not in the cache will get sent out to the network with fetch request We can go a step further and cache requests that are not in the cache That way we will fetch a resource from the network and store it into the cache If our app goes offline for some reason that resource will still be available yay This is what our fetch event handler should look like const putInCache async request response gt const cache await caches open version if request method GET console log Cannot cache non GET requests return await cache put request response const cacheFirst async request gt const responseFromCache await caches match request if responseFromCache return responseFromCache const responseFromNetwork await fetch request we need to clone the response because the response stream can only be read once putInCache request responseFromNetwork clone return responseFromNetwork self addEventListener fetch event gt event respondWith cacheFirst event request Here we define the putInCache function that puts the request and its response into the cache If you notice we also check for a request method By design we cannot cache non GET requests in the Cache Storage API After that we changed the cacheFirst function to call the putInCache function with the request object and the clone of a response We have to clone the response because request and response streams can only be read once Then we return the original response to the browser And that is it this is the basic service worker that will cache all GET requests that go from your website to the network This setup can be a great first step if you plan to make your app work offline You can play around with different caching strategies let s quickly go over them Cache FirstWe implemented here a cache first approach where we first try to serve a request from the cache if it is available Network FirstYou can try and implement a network first approach where we normally send out the request to the network and cache it Then when the request can t be made the site lost connectivity for example  ーwe serve the failed request from the cache Stale While RevalidateThere s also a stale while revalidate approach that will use a cached version if available but it will fetch an update and put it in the cache for next time We could also go on and make sure that a user gets a fallback response in case the resource is not in the cache and it can t be fetched over the network But this should be enough to get you started on a service worker Instead I d like us to compare the difference between service workers and workers in general Let s dive into that in the next section Service workers versus other workersNow that we have an understanding of service workers we can look over other types of web workers and how they differ from each other Let s start with how similar web workers and service workers are Web workers and service workers are two different types of background scripts available to websites in the browser Both web workers and service workers have some things in common They both run in a different thread without blocking the main JavaScript thread and the user interface They can t interact with the DOM directly and they have limited access to browser APIs They both are web workers But service workers are just a specialized version of web workers And the differences between them As we mentioned before service workers allow you to intercept network requests via the fetch event and to listen for Push API events in the background via the push event Web workers can t do that A page can spawn multiple web workers but only one service worker controls all the active tabs under the scope it was registered with The lifespan of the web worker is tightly coupled to the tab it belongs to while the service worker s lifecycle is independent of it When you close the tab where a web worker is running the worker will be terminated A service worker can continue running in the background even when the site that registered it doesn t have any active tabs open Service workers only run over HTTPS for security reasons Being able to modify network requests they are wide open to man in the middle attacks which is why they are only allowed on secure connections In Firefox Service Worker APIs are also hidden and cannot be used when the user is in private browsing mode There s an open bug for that if you want to track it There are also shared workers They are workers that can be utilized by multiple scripts running in different windows iframes and similar as long as they are in the same domain as the worker The scripts must communicate via an active port so they are more complex than the standard workers or service workers Besides these you can also utilize worklets A worklet interface is a lightweight version of web workers and gives developers access to low level parts of the rendering pipeline Worklets can be used to run JavaScript and WebAssembly code to perform graphics rendering or audio processing where high performance is required Summing upPhew what a ride We learned the basics of service workers but let s go over it once again Here are things to remember A service worker is a specialized worker that performs away from the main JavaScript thread A service worker can act as middleware between your site and the network To have a service worker on your website it has to be first downloaded installed and then activated If you re updating an existing service worker the previous service worker must be unloaded from the page or you can instead skip waiting for that Service workers only run over HTTPS for security reasons One of the main use cases for a service worker is to cache resources As far as web workers are concerned they are mostly used to delegate work from the main thread while the page is open As soon as the page is closed the classic worker is terminated as well If you re interested in the code from this blog post I pushed it to a repository on GitHub You can check it out there it has a small index html page that showcases how you can cache resources That s all folks next time we will go into how to debug service workers even though we showed a glimpse of where you can do that and we can show how to use service workers in some other use case Until then thanks for reading and catch you in the next one Originally published by Nikola Đuza in Uploadcare Blog	2022-12-26 00:19:12
海外科学	BBC News - Science & Environment	Water pipe robots could stop billions of litres leaking	https://www.bbc.co.uk/news/science-environment-64052740?at_medium=RSS&at_campaign=KARANGA	miniature	2022-12-26 00:01:20
金融	ニッセイ基礎研究所	老後の備えは投資から貯蓄へ、の傾向強まる（中国）	https://www.nli-research.co.jp/topics_detail1/id=73369?site=nli	経済成長が失速し、株式など金融市場、不動産市場が厳しさを増す中で、年は老後の備えも投資型の商品から安定した貯蓄型の商品への移行がみられた。	2022-12-26 09:56:45
金融	ニッセイ基礎研究所	米個人所得・消費支出（22年11月）－PCE価格の総合、コア指数ともに前月比、前年同月比が前月から低下	https://www.nli-research.co.jp/topics_detail1/id=73370?site=nli	前年同月比は、エネルギー価格指数が前月と前月から伸びは鈍化もヵ月連続で桁の上昇となった図表。	2022-12-26 09:14:28
ニュース	BBC News - Home	Iran protests: 'No going back' as unrest hits 100 days	https://www.bbc.co.uk/news/world-middle-east-64062900?at_medium=RSS&at_campaign=KARANGA	crackdown	2022-12-26 00:20:06
ニュース	BBC News - Home	Foreign aid groups halt work after Taliban ban on female staff	https://www.bbc.co.uk/news/world-asia-64090549?at_medium=RSS&at_campaign=KARANGA	afghanistan	2022-12-26 00:31:06
ニュース	BBC News - Home	Water pipe robots could stop billions of litres leaking	https://www.bbc.co.uk/news/science-environment-64052740?at_medium=RSS&at_campaign=KARANGA	miniature	2022-12-26 00:01:20
ニュース	BBC News - Home	Leak-hunting 'pipebots' will help us save water	https://www.bbc.co.uk/news/science-environment-64069533?at_medium=RSS&at_campaign=KARANGA	miniature	2022-12-26 00:00:42
ニュース	BBC News - Home	Buy now, pay later: Things you need to know about the loan schemes	https://www.bbc.co.uk/news/business-63910427?at_medium=RSS&at_campaign=KARANGA	borrowing	2022-12-26 00:22:21
ニュース	BBC News - Home	TV lookahead: 23 highlights to look out for in 2023	https://www.bbc.co.uk/news/entertainment-arts-64005663?at_medium=RSS&at_campaign=KARANGA	treats	2022-12-26 00:51:07
ニュース	BBC News - Home	How astronauts inspired the creation of Teletubbies	https://www.bbc.co.uk/news/stories-63976499?at_medium=RSS&at_campaign=KARANGA	teletubbies	2022-12-26 00:25:10
ビジネス	不景気.com	千葉の内装工事「関東興機」に破産決定、負債12億円 - 不景気com	https://www.fukeiki.com/2022/12/kanto-koki.html	千葉県千葉市	2022-12-26 00:16:04
北海道	北海道新聞	宇野、世界代表選考に珍しく苦言　島田落選、「うれしく思えない」	https://www.hokkaido-np.co.jp/article/780573/	世界選手権	2022-12-26 09:20:19
北海道	北海道新聞	１２５年ぶり「１横綱１大関」　琴ノ若、若元春が新小結	https://www.hokkaido-np.co.jp/article/780584/	大相撲初場所	2022-12-26 09:20:03
北海道	北海道新聞	コンサドーレ、砂川氏がトップチームコーチに　ブルーノ氏はＣ大阪へ	https://www.hokkaido-np.co.jp/article/780437/	砂川誠	2022-12-26 09:16:29
北海道	北海道新聞	コリトサウルス、米国にも　特定の決め手は「とさか」	https://www.hokkaido-np.co.jp/article/780586/	米国	2022-12-26 09:12:10
北海道	北海道新聞	長万部で震度２　津波の心配なし	https://www.hokkaido-np.co.jp/article/780596/	津波の心配	2022-12-26 09:09:00
北海道	北海道新聞	宇野や三浦、木原組ら代表　さいたまで世界フィギュア	https://www.hokkaido-np.co.jp/article/780559/	世界フィギュア	2022-12-26 09:08:26
マーケティング	MarkeZine	TikTokユーザーはどんな人？プロファイル分析から「TikTok売れ」の背景を考える	http://markezine.jp/article/detail/40796	TikTokユーザーはどんな人プロファイル分析から「TikTok売れ」の背景を考える次世代の動画配信プラットフォームとして注目を集めるTikTok。	2022-12-26 09:30:00