投稿時間:2023-08-13 23:18:01 RSSフィード2023-08-13 23:00 分まとめ(18件)

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IT	気になる、記になる…	Apple、誕生10周年に合わせて大規模刷新した｢Apple Watch X｣を計画か ｰ バンドの取り付け方法の変更も検討中	https://taisy0.com/2023/08/13/175312.html	apple	2023-08-13 13:33:03
IT	気になる、記になる…	｢iPhone SE 4｣は｢iPhone 14｣ベースに ｰ USB-Cポートやアクションボタンを搭載との噂	https://taisy0.com/2023/08/13/175307.html	iphone	2023-08-13 13:10:43
TECH	Techable（テッカブル）	ゲームコントローラでロボットを遠隔操作。どこからでも点検できるソリューション、施工現場で導入	https://techable.jp/archives/217228	remotebas	2023-08-13 13:00:27
AWS	lambdaタグが付けられた新着投稿 - Qiita	Lambda（Node.js）でBox Platform APIを使用する	https://qiita.com/TaaaZyyy/items/b8fb2cde152b675aeb98	boxplatform	2023-08-13 22:37:35
python	Pythonタグが付けられた新着投稿 - Qiita	pytest-asyncio が入っているのに非同期関数のテストがスキップされる。	https://qiita.com/A_kBTlnQ/items/9f5dab0a4f6747994351	pytest	2023-08-13 22:29:34
js	JavaScriptタグが付けられた新着投稿 - Qiita	【Spring Boot】簡易メモアプリ作成過程【駆け出し】	https://qiita.com/Takatsuna/items/7be62afa19cb2cd92b88	spring	2023-08-13 22:24:19
AWS	AWSタグが付けられた新着投稿 - Qiita	Lambda（Node.js）でBox Platform APIを使用する	https://qiita.com/TaaaZyyy/items/b8fb2cde152b675aeb98	boxplatform	2023-08-13 22:37:35
Git	Gitタグが付けられた新着投稿 - Qiita	commit.templateのすすめ	https://qiita.com/hhujk5/items/09d2d8aa299528f03ed2	committemplate	2023-08-13 22:08:20
Ruby	Railsタグが付けられた新着投稿 - Qiita	RailsプロジェクトでJavaScriptが動作しない問題とその解決方法	https://qiita.com/junpei314/items/8c21c557493074897d91	javascript	2023-08-13 22:54:26
海外TECH	MakeUseOf	The 8 Best Tech Careers in the Military	https://www.makeuseof.com/best-tech-careers-in-military/	careers	2023-08-13 13:16:21
海外TECH	MakeUseOf	Try These 8 Online HypnoBirthing Courses and Classes to Relax Into Birth	https://www.makeuseof.com/best-online-hypnobirthing-courses-and-classes/	birthgiving	2023-08-13 13:00:24
海外TECH	MakeUseOf	Has Windows Security Stopped Working on your Windows 11? Here's How You Can Fix It	https://www.makeuseof.com/windows-11-fix-windows-security/	Has Windows Security Stopped Working on your Windows Here x s How You Can Fix ItWindows Security is crucial for a PC s security but it can sometimes malfunction Here are the different ways to fix it	2023-08-13 13:00:24
海外TECH	DEV Community	Caches	https://dev.to/scorcism/caches-gk5	Caches What are chaches Caching is like having a quick access memory for information so you don t have to fetch it from the original source every time you need it It s like keeping your favourite apps on the home screen so you don t have to scroll or search for them There are different types of caches that help make things faster in different situations Hardware Level CachesOS Level Caches Network Level CachesLet s Deep dive into each of them Hardware Level CachesHardware level caches are an essential component of modern computer architectures designed to improve data access speeds and overall system performance Here are the primary types of hardware level caches commonly found in computers L Cache Level Cache Located closest to the CPU cores Divided into separate instruction cache Li and data cache Ld Provides extremely fast access to frequently used instructions and data L Cache Level Cache Positioned between L cache and main memory Larger in size compared to L cache Helps reduce memory latency by storing additional data L Cache Level Cache Shared among multiple CPU cores Larger capacity than L cache Enhances data sharing and synchronization between cores Translation Lookaside Buffer TLB Cache Facilitates virtual to physical memory address translation Accelerates memory access by storing frequently used address translations Store virtual physical address Disk Controller Cache Found in storage devices like hard drives and SSDs Temporarily stores read and write operations to enhance I O performance GPU Cache Specific to graphics processing units GPUs Stores texture data and intermediate calculations for faster graphics rendering Memory Cache Temporarily stores frequently accessed data from main memory RAM Reduces memory access latency and enhances system responsiveness Disk Cache Temporarily stores frequently accessed data from disk drives Improves read and write performance by minimizing disk access There are many others types of harware caches but these are the imp ones Now moving to OS Level Caches OS Level CachesOperating system level caches play a crucial role in enhancing overall system performance and responsiveness by storing frequently accessed data and instructions Here are some common types of OS level caches File System Cache Caches recently accessed file data in memory Improves file read and write operations by reducing disk access Enhances overall file system performance Memory Cache Page Cache Caches portions of the main memory RAM for faster data retrieval Reduces the need to access data directly from slower storage devices Directory Cache Dentry Cache Stores recently accessed directory and file entry data Speeds up directory navigation and file path resolution Inode Cache Caches metadata of recently accessed files such as permissions and timestamps Improves file system navigation and reduces metadata lookups Translation Lookaside Buffer TLB Caches virtual to physical memory address translations Accelerates memory access by avoiding repeated translation table lookups Kernel Caches Caches portions of the kernel code and data structures Enhances system responsiveness and reduces kernel access latency DNS Cache Stores recently resolved domain names and their corresponding IP addresses Reduces the need for repeated DNS lookups improving network performance IPC Inter Process Communication Caches Caches communication related data between processes Enhances efficiency in data sharing and communication There are other OS Level caches such as Metadata Cache which store metadata about file directories and resouces Package Caches Caches software package information and installation files Executable Caches Stores copies of recently executed programs or executable files Now moving to Network Level Cache Network Level CachesNetwork caching plays a crucial role in optimizing data transmission and reducing latency in network communication Here are some common types of network caches Web Browser Cache Caches web page resources HTML CSS JavaScript images locally Speeds up subsequent visits to websites by avoiding repeated downloads Content Delivery Network CDN Cache Caches copies of web content on distributed servers closer to users Improves content delivery and reduces latency for geographically dispersed users Proxy Server Cache Caches frequently requested web pages and resources on a proxy server Reduces the load on the origin server and improves response times Gateway Cache Caches data between a client and a remote server Enhances data transmission efficiency and reduces network congestion DNS Cache Stores recently resolved domain names and their corresponding IP addresses Speeds up domain name resolution and reduces DNS lookup times Router Cache Caches routing information and network paths for faster data forwarding Improves router performance and reduces network delays Streaming Cache Caches streaming media content such as videos and audio Reduces buffering and improves playback quality for online streaming services Database Query Cache Caches frequently executed database queries and their results Accelerates database query response times and reduces database load Message Broker Cache Caches frequently published or subscribed messages in a message broker Optimizes message delivery and reduces redundant data transmission API Cache Caches responses from API endpoints to reduce redundant API requests Enhances API performance and conserves network resources Load Balancer Cache Caches data on load balancers to improve distribution efficiency Reduces the load on backend servers and enhances request handling Gateway Cache Caches data between different network segments or protocols Enhances data transfer between heterogeneous networks I know this is a lot but for learning you can remember the gist of that and these are very simple to remember but the cache is that you must remember the name so to make the other lines If you have interest in open source you can contribue to my projects One LinerClick CounterIf the article helps you leave a like follow or anything You can follow me on LinkedIn GitHub Dev to and hashnode Bye	2023-08-13 13:47:08
海外TECH	DEV Community	Remote Work 2.0: The Tools, Trends, and Challenges of the Post-Pandemic Work Era	https://dev.to/thenomadevel/remote-work-20-the-tools-trends-and-challenges-of-the-post-pandemic-work-era-3be1	Remote Work The Tools Trends and Challenges of the Post Pandemic Work EraHey there awesome folks It s Nomadev here back with another trending topic for all of you If you ve been following my posts you know I m all about AI open source web development and helping developers level up their skills and land those dream jobs Today we re diving deep into the world of remote work and its evolution And yes we ll also touch upon the importance of contributing to open source So let s get started First off a big shoutout to all of you who ve been part of this remote work journey Whether you ve been working from your cozy bedroom or that coffee shop down the lane we ve all experienced the seismic shift in the way we work The pandemic might have pushed us into this but hey look at where we are now Embracing change adapting to new tools and of course contributing to open source because that s how we roll Open source isn t just about code it s about community collaboration and making tech accessible to everyone And in this era of remote work it s more crucial than ever The Evolution of Remote WorkPre pandemic Era Remember the days when remote work was just a fancy perk offered by a few companies It was a time when working from home was an exception not the norm During the Pandemic Boom The world changed and so did our workstations From office desks to kitchen tables we adapted It wasn t just about work it was about staying connected keeping the team spirit alive and yes those endless Zoom calls Post pandemic Era As we step into this new era it s not just about working remotely It s about hybrid models flexibility and finding that perfect balance Companies are realizing that it s not about where you work but how you work And for many of us it s a blend of office days and WFH work from home for the uninitiated Challenges in the New Era of Remote WorkIt s not all sunshine and rainbows in the remote work world While we ve seen some fantastic advancements and benefits there are challenges that we need to address Isolation and Mental Health Let s face it working alone can get well lonely The lack of social interactions and office banter can take a toll on our mental well being It s crucial to find ways to connect even if it s just a virtual coffee break Communication Barriers Ever felt that a text message just didn t convey the tone Or that video call lag made discussions a tad awkward Effective virtual communication is an art and we re all still learning Security Concerns With great flexibility comes great responsibility Ensuring data security and privacy in a decentralized work environment is paramount No more Oops I shared the company s secret sauce on a public server moments please The Future of Remote WorkLooking ahead the future of remote work is bright but it s going to be different Sustainable Work Environments It s not just about working from home it s about creating a sustainable work environment Whether it s ergonomic furniture mental health breaks or setting boundaries the future is all about holistic well being Training and Skill Development The digital age is evolving and so should we Continuous learning upskilling and adapting to new tools will be the name of the game Company Culture in a Virtual World Building and maintaining a company culture without physical interactions is challenging But hey we ve seen virtual team building activities online office parties and more The future is virtual and so is the culture The Shift Towards AI in DevelopmentAlright tech enthusiasts here s the juicy bit AI is not just about robots and sci fi movies it s reshaping the way we work The Decline of Traditional Software Development With AI driven tools becoming more sophisticated many tasks traditionally done by software developers are being automated No more manual coding for standard website templates Rise of AI based Developers As AI takes center stage there s a growing demand for developers who can integrate AI solutions If you re looking to future proof your career this is where you should be heading AI in the Remote Job Market Companies are on the hunt for AI based developers With the capabilities of AI expanding the remote job market will see a significant shift towards AI centric roles in the next five years So gear up and ride the AI wave Tools Powering Remote Work The evolution of remote work has been significantly influenced by the rise of Artificial Intelligence AI These AI powered tools have not only made remote work more efficient but have also enhanced collaboration productivity and decision making Here are some of the top AI tools that are shaping the future of remote work Zoom A popular video conferencing tool that uses AI for background noise reduction virtual backgrounds and meeting transcriptions Visit ZoomSlack A team collaboration platform that integrates with various AI plugins to automate tasks and enhance communication Visit SlackTrello A project management tool that utilizes AI to predict task completion times suggest optimizations and more Visit TrelloGrammarly An AI powered writing assistant that helps in improving the clarity engagement and delivery of your messages Visit GrammarlyOtter ai A tool that provides real time transcription services for meetings lectures and conversations Visit Otter aiAI Assisted Jobs Job board for language model prompt engineering and Chat GPT positions Visit AI Assisted JobsAI Job Interview Coach AI tool for interview preparation job search and coaching Visit AI Job Interview CoachJoblens This AI system searches and suggests jobs based on your preferences Visit JoblensAI Interview Coach Provides job interview preparation with personalized guidance questions and answers Visit AI Interview CoachJobWizard An AI tool that auto fills generates answers and tracks job applications Visit JobWizardApplAI AI job prep tool helps you shine in interviews Visit ApplAIAuto Apply Auto applies to top jobs for you get interviews in your inbox Visit Lazy ApplyProdigy AI Offers software engineers career coaching skill assessment and job matching Visit Prodigy AITalentGenius Coach Uses AI to provide personalized career development and job search guidance Visit TalentGenius CoachAiToolHunt A directory to discover and compare new AI tools Visit AiToolHuntIf you re specifically looking for websites to apply for remote jobs I ve got you covered Check out my article on the Top Websites to Find Remote Jobs Wrapping It UpThe landscape of remote work is evolving rapidly and AI is at the forefront of this transformation As we ve explored the tools and trends shaping the future of remote work are not just about making our jobs easier but also about enhancing our capabilities fostering collaboration and opening up new avenues of opportunity For those of you looking to stay ahead of the curve it s essential to keep an eye on these advancements and adapt accordingly And remember the journey of navigating the remote work realm and the world of AI doesn t have to be taken alone I Nomadev am here to guide and share insights regularly If you re keen on diving deeper into the world of AI remote jobs and tech trends don t forget to follow me on Twitter I m always posting about the latest in AI and remote work Plus if you have any queries or are looking for a personalized roadmap for your career feel free to reach out Let s embark on this exciting journey together and shape the future of work	2023-08-13 13:34:57
海外TECH	DEV Community	The Complete Guide to Becoming a Web Developer: Part 7	https://dev.to/aradwan20/the-complete-guide-to-becoming-a-web-developer-part-7-1nbd	The Complete Guide to Becoming a Web Developer Part In the world of web development there are a few tools that have revolutionized the way we build web applications and Node js NPM and Express are at the forefront of this revolution These tools have made it possible for developers to use JavaScript a language traditionally used for front end development for server side programming as well leading to the rise of full stack JavaScript development IntroductionFirst Look at Node jsInstalling Node js and NPMExploring Modules and the NPM WorldUnderstanding Modules in Node jsNPMInstalling and Using NPM PackagesCreating Servers with Express jsWhat is Express js Setting Up an Express ServerHandling Requests and ResponsesCreating Dynamic HTML with TemplatingIntroduction to Templating EnginesUsing EJS for Dynamic HTML GenerationTemplating Best PracticesDefining RESTful RoutesUnderstanding RESTful ArchitectureDefining Routes in Express jsRoute Parameters and Query StringsMiddleware in Express jsUnderstanding MiddlewareUsing Built In Express MiddlewareCreating Custom MiddlewareBut what if we didn t call next Error Handling in Express jsHandling Synchronous ErrorsHandling Asynchronous ErrorsThe Default Error HandlerWriting Error HandlersDatabase Integration with Express jsIntroduction to MongoDBUsing Mongoose for MongoDB InteractionCRUD Operations with MongooseBest practices for working with Node js NPM and ExpressCommon Mistakes and How to Avoid ThemConclusionAdditional ResourcesIntroductionNode js is a runtime environment that allows us to execute JavaScript on the server side It s built on Chrome s V JavaScript engine and brings event driven programming to web servers enabling the development of fast web servers in JavaScript NPM which stands for Node Package Manager is a tool that comes with Node js when you install it It s a package manager for the JavaScript programming language and is the default package manager for Node js It allows developers to install share and package software and manage dependencies in their projects Express on the other hand is a fast unopinionated and minimalist web framework for Node js It provides a simple way to write servers and web applications and has become a standard server framework for Node js It is built to manage routes requests and views along with handling APIs and building robust web applications and APIs These tools are essential for any web developer because they provide a complete package for developing server side applications Node js allows you to use JavaScript on the server NPM provides a way to manage packages and dependencies and Express makes it easy to set up your server and add routes middleware and more In this guide we will dive deep into these tools starting from your first contact with Node js exploring modules and the NPM world creating servers with Express js creating dynamic HTML with templating and defining RESTful routes By the end of this guide you will have a solid understanding of these tools and how to use them in your web development journey So let s get started First Look at Node jsNode js is an asynchronous event driven JavaScript runtime designed to build scalable network applications It s highly efficient for handling many connections concurrently In a typical Hello World example upon each connection a callback is fired but if there is no work to be done Node js will sleep This is in contrast to the more common concurrency model where OS threads are employed which can be relatively inefficient and difficult to use Here s a simple example of a Node js program const http require http const hostname const port const server http createServer req res gt res statusCode res setHeader Content Type text plain res end Hello World server listen port hostname gt console log Server running at http hostname port In this example we re creating a simple HTTP server that responds with Hello World for every request The server is listening on port When you run this program you should see the message Server running at in your terminal Node js is similar in design to systems like Ruby s Event Machine and Python s Twisted but it takes the event model a bit further by presenting an event loop as a runtime construct instead of as a library This means that Node js enters the event loop after executing the input script and exits when there are no more callbacks to perform much like browser JavaScript HTTP is a first class citizen in Node js designed with streaming and low latency in mind making Node js well suited for the foundation of a web library or framework Despite being designed without threads Node js can still take advantage of multiple cores in your environment through child processes and the cluster module which allows you to share sockets between processes to enable load balancing over your cores Now that we have a basic understanding of what Node js is let s move on to installing Node js and NPM Installing Node js and NPMInstalling Node js and NPM Node Package Manager is a straightforward process Node js is the runtime that executes JavaScript code outside of a browser and NPM is the default package manager for Node js It s used to install Node js programs from the npm registry organize versions and dependencies of these programs and make it easier to share and distribute code You can download Node js and NPM from the official Node js website There are different versions available but for most users the LTS Long Term Support version is the best choice The LTS version is stable and receives long term support After downloading the installer run it and follow the prompts in the setup wizard After installation you can verify that Node js and NPM are installed correctly by opening a terminal or command prompt and running the following commands node vnpm vThe node v command should print the Node js version and npm v should print the NPM version If you see version numbers that means Node js and NPM are installed correctly Now that we have Node js and NPM installed let s write our first Node js program We ll create a simple program that prints Hello World to the console Create a new file named app js and open it in your text editor Add the following code to the file console log Hello World Save the file and go back to your terminal Navigate to the directory where you saved app js and run the following command node app jsYou should see Hello World printed on the console Congratulations you ve just run your first Node js program In the next section we ll dive deeper into the world of Node js and explore modules and the NPM ecosystem Exploring Modules and the NPM WorldIn the world of Node js a package contains all the files you need for a module Modules are JavaScript libraries that you can include in your project NPM which stands for Node Package Manager is a tool that allows you to easily download and use these packages When you install Node js NPM is automatically installed on your computer ready to use Understanding Modules in Node jsIn Node js modules are a set of functions that you want to include in your application You can think of them as JavaScript libraries because they are reusable pieces of code that perform a specific task Node js has a built in module system that allows you to include modules in your code with the require function Here s an example of how you can include the built in HTTP module in your Node js application var http require http In this example the require function returns an object because the HTTP module returns its functionality as an object You can use this object to create a server make a request to a server and perform other HTTP related tasks NPMNPM is a package manager for Node js It hosts thousands of free packages that you can download and use in your projects When you install Node js NPM is also installed on your computer so you re ready to start using it right away Installing and Using NPM PackagesDownloading and installing a package with NPM is easy You just need to open your command line interface and tell NPM to download the package you want For example if you want to download a package called upper case you would type the following command npm install upper caseAfter running this command NPM creates a folder named node modules where it places the upper case package All packages you install in the future will also be placed in this folder To use the upper case package in your Node js application you would include it with the require function just like you would with a built in module var uc require upper case Now you can use the upperCase function from the upper case package to convert a string to upper case console log uc upperCase Hello World Outputs HELLO WORLD In this section we ve just scratched the surface of what you can do with modules and NPM in Node js Creating Servers with Express jsCreating servers with Express js is a straightforward process that allows developers to quickly get a server up and running Express js is a minimal and flexible Node js web application framework that provides a robust set of features for web and mobile applications It simplifies the process of writing server code and it s perfect for building APIs and handling HTTP requests What is Express js Express js is a web application framework for Node js It s designed for building web applications and APIs It s minimal meaning it doesn t come with everything out of the box Instead it provides a simple interface for building server side JavaScript applications and you can extend it with various plugins for added functionality Setting Up an Express ServerTo set up an Express server you first need to install Express js You can do this by running npm install express in your terminal Once Express js is installed you can create a new file let s call it app js and write the following code const express require express const app express const port app get req res gt res send Hello World app listen port gt console log Server is running at http localhost port This code creates a new Express application and sets up a single route that responds with Hello World The app listen function starts the server on the specified port Handling Requests and ResponsesIn the example above we used the app get function to set up a route for HTTP GET requests The first argument is the path and the second argument is a callback function that takes a request and a response object The request object req contains information about the HTTP request such as the URL HTTP headers and any data sent by the client The response object res is used to send data back to the client In our callback function we simply call res send Hello World to send a response back to the client This will send the string Hello World as the HTTP response body Express js provides a number of other functions for handling different types of HTTP requests like app post for POST requests and for sending different types of responses like res json for sending JSON data Remember the beauty of Express js lies in its simplicity and flexibility You can build a wide range of applications using just these basic concepts and you can extend your application with middleware and plugins as needed Creating Dynamic HTML with TemplatingCreating dynamic HTML is a fundamental part of web development It allows us to create web pages that can change and adapt based on data user interactions or other factors One of the ways we can create dynamic HTML in Node js applications is by using templating engines Introduction to Templating EnginesA templating engine is a tool that allows developers to write HTML markup with dynamic values These dynamic values are placeholders that get replaced with actual data when the page is rendered This allows us to create a single template for a web page and then use it to generate many different pages each with its own data There are many templating engines available for Node js including EJS Pug formerly Jade Handlebars and many others They all have their own syntax and features but they all serve the same basic purpose to make it easier to generate dynamic HTML Using EJS for Dynamic HTML GenerationEJS or Embedded JavaScript is a simple templating engine that lets you generate HTML markup with plain JavaScript It s easy to use and has a syntax that s similar to regular HTML which makes it a good choice for beginners To use EJS you first need to install it using NPM npm install ejsThen in your Express js application you can tell Express to use EJS as its templating engine like this app set view engine ejs Now you can create EJS templates in your views directory Here s an example of what an EJS template might look like lt DOCTYPE html gt lt html gt lt head gt lt title gt My App lt title gt lt head gt lt body gt lt h gt Welcome lt user name gt lt h gt lt p gt You have lt messages length gt new messages lt p gt lt body gt lt html gt In this template lt user name gt and lt messages length gt are placeholders that will be replaced with actual data when the template is rendered To render an EJS template you can use the res render function in Express app get req res gt res render index user name John messages Templating Best PracticesWhen working with templates it s important to keep a few best practices in mind Keep your templates simple Templates are meant to generate HTML not to contain complex logic If you find yourself writing a lot of JavaScript in your templates consider moving some of that logic into your controllers or models Don t mix data fetching with rendering Your templates shouldn t be responsible for fetching data from a database or an API Fetch the data first then pass it to the template for rendering Escape user input to prevent XSS attacks Most templating engines including EJS automatically escape user input to prevent cross site scripting XSS attacks However it s still a good idea to be aware of this risk and to always escape user input if you re inserting it into your templates Use partials for reusable components Most templating engines allow you to create partials which are small templates that you can include in other templates This is great for things like headers footers or any other components that you want to reuse across multiple pages Defining RESTful RoutesDefining routes is a key part of building any web application In this section we ll explore what RESTful architecture is how to define routes in Express js and how to work with route parameters and query strings Understanding RESTful ArchitectureREST or Representational State Transfer is an architectural style for designing networked applications A RESTful web application exposes information about itself in the form of resources data entities that clients can interact with In a RESTful application each resource is identified by a specific URL and the server responds to different HTTP methods like GET POST PUT DELETE etc which represent different operations that can be performed on the resource Here s a simple example of what RESTful routes might look like for a blog application GET posts Retrieve a list of all postsPOST posts Create a new postGET posts Retrieve a specific postPUT posts Update a specific postDELETE posts Delete a specific postDefining Routes in Express jsIn Express js you can define routes using methods of the Express app object that correspond to HTTP methods Here s how you might define the routes for the blog application mentioned above const express require express const app express app get posts req res gt Retrieve and return all posts app post posts req res gt Create a new post app get posts id req res gt Retrieve and return a specific post app put posts id req res gt Update a specific post app delete posts id req res gt Delete a specific post app listen gt console log Server is running on port Route Parameters and Query StringsIn the example above id is a route parameter Route parameters are named URL segments that you can use to capture the values specified at their position in the URL You can access these values using req params For example in the route GET posts id if you navigate to posts req params id will be Query strings on the other hand are a way to send data to the server as part of the URL but not as part of the route They are included after a question mark in the URL and are composed of key value pairs separated by ampersands For example in the URL posts category tech amp author John the query string is category tech amp author John and you can access these values in Express using req query So req query category will be tech and req query author will be John Middleware in Express jsMiddleware is a fundamental concept in Express js that you ll use in almost every project In this section we ll explore what middleware is how to use the built in middleware provided by Express and how to create your own custom middleware Understanding MiddlewareMiddleware functions are functions that have access to the request object req the response object res and the next function in the application s request response cycle The next function is a function in the Express router which when invoked executes the middleware succeeding the current middleware Middleware functions can perform the following tasks Execute any code Make changes to the request and the response objects End the request response cycle Call the next middleware in the stack If the current middleware function does not end the request response cycle it must call next to pass control to the next middleware function Otherwise the request will be left hanging Using Built In Express MiddlewareExpress js comes with several built in middleware functions that you can use right out of the box Here are a few examples express json This is a built in middleware function in Express It parses incoming requests with JSON payloads and is based on body parser express static This middleware function is used to serve static files You pass the name of the directory to express static to start serving the files directly For example if you store images in a directory named images you can use express static images to start serving the images Here s how you might use these middleware functions in an Express app const express require express const app express app use express json app use express static images app listen gt console log Server is running on port Creating Custom MiddlewareIn addition to using the built in middleware you can also create your own custom middleware Here s an example of a simple custom middleware function that logs the current date and time for each request const express require express const app express app use req res next gt console log Time Date now next app listen gt console log Server is running on port In this example app use is used to load the middleware function The middleware function logs the current date and time and then calls next to pass control to the next middleware function in the stack But what if we didn t call next If you don t call next at the end of your middleware function the request response cycle will halt at that middleware This means that any middleware functions that are supposed to run after the current one will not be executed This can lead to issues where the server doesn t send a response back to the client causing the client to hang or timeout Here s an example to illustrate this const express require express const app express app use req res next gt console log Time Date now next If we don t call next the request stops here app get req res gt res send Hello world app listen gt console log Server is running on port In this example if you make a GET request to the root route you won t receive the Hello world response This is because the middleware function that logs the time doesn t call next so the request never reaches the route handler for the root route However there are cases where you might intentionally want to end the request response cycle in a middleware function without calling next For example you might have a middleware function that checks if a user is authenticated If the user is not authenticated you could send a response with an error message and not call next effectively preventing the request from proceeding to the route handler Error Handling in Express jsHere s a detailed overview of error handling in Express js Handling Synchronous ErrorsErrors that occur in synchronous code inside route handlers and middleware require no extra work If synchronous code throws an error then Express will catch and process it For example app get req res gt throw new Error BROKEN Express will catch this on its own Handling Asynchronous ErrorsFor errors returned from asynchronous functions invoked by route handlers and middleware you must pass them to the next function where Express will catch and process them For example app get req res next gt fs readFile file does not exist err data gt if err next err Pass errors to Express else res send data Starting with Express route handlers and middleware that return a Promise will call next value automatically when they reject or throw an error The Default Error HandlerExpress comes with a built in error handler that takes care of any errors that might be encountered in the app This default error handling middleware function is added at the end of the middleware function stack If you pass an error to next and you do not handle it in a custom error handler it will be handled by the built in error handler the error will be written to the client with the stack trace The stack trace is not included in the production environment Writing Error HandlersDefine error handling middleware functions in the same way as other middleware functions except error handling functions have four arguments instead of three err req res next For example app use err req res next gt console error err stack res status send Something broke You define error handling middleware last after other app use and routes calls For more details you can refer to the Express js Error Handling Guide Database Integration with Express jsIntroduction to MongoDBMongoDB is a popular NoSQL database that uses a document oriented data model It s a database of choice for many Node js applications including Express js apps MongoDB stores data in a format that s similar to JSON which makes it intuitive to use from JavaScript It s also highly scalable and can handle large amounts of data distributed over multiple servers Using Mongoose for MongoDB InteractionTo interact with MongoDB in a Node js application we often use an Object Data Modeling ODM library and Mongoose is one of the most popular choices Mongoose acts as a front end to MongoDB and provides a simple and intuitive API for interacting with the database It allows you to define schemas for your data validate data before it s saved and define instance and static methods for your data models To use Mongoose you first need to install it in your project using npm npm install mongooseThen you can require it in your code and use it to define schemas and models const mongoose require mongoose const Schema mongoose Schema const SomeModelSchema new Schema a string String a date Date const SomeModel mongoose model SomeModel SomeModelSchema In this example SomeModelSchema is a schema that defines the structure of the documents in the MongoDB collection SomeModel is a model that provides methods for querying the database creating new documents and more CRUD Operations with MongooseMongoose provides methods for performing Create Read Update and Delete CRUD operations on the database Create You can create a new document and save it to the database using the save method of a Mongoose model instance const someModelInstance new SomeModel a string Hello a date Date now someModelInstance save err gt if err return handleError err saved Read You can retrieve documents from the database using the find method of a Mongoose model SomeModel find a string Hello err docs gt if err return handleError err docs is an array of all documents that match the query Update You can update documents in the database using the updateOne updateMany or findOneAndUpdate methods of a Mongoose model SomeModel updateOne a string Hello a string Hi err res gt if err return handleError err res nModified is the number of documents updated Delete You can delete documents from the database using the deleteOne deleteMany or findOneAndDelete methods of a Mongoose model SomeModel deleteOne a string Hi err gt if err return handleError err deleted These are just the basics of using Mongoose with MongoDB in an Express js application Mongoose provides many more features such as data validation middleware and population which can help you build robust and efficient web applications We will learn more about it in future articles Best practices for working with Node js NPM and ExpressCode Organization and Structure Organize your code into modules and use the module exports and require syntax to import and export functions objects or values from one module to another This will make your code more readable and maintainable greet jsmodule exports function greet name return Hello name app jsconst greet require greet console log greet World Outputs Hello World Security Best Practices Always validate and sanitize user input to protect your application from security threats like SQL Injection and Cross Site Scripting XSS Use packages like helmet to secure your Express apps by setting various HTTP headers and express validator for server side data validation const express require express const helmet require helmet const app express app use helmet Performance Optimization Use the Node js built in cluster module to spawn a process for each core on your server s CPU This allows your application to handle more traffic and operate faster Also consider using a reverse proxy like Nginx to serve static files and cache content which can significantly improve your application s performance const cluster require cluster const numCPUs require os cpus length if cluster isMaster for let i i lt numCPUs i cluster fork else const express require express const app express Error Handling Always handle errors properly in your Node js applications Use middleware for centralized error handling in your Express js applications This will help you to avoid unhandled promise rejections and uncaught exceptions that can crash your Node js process app use err req res next gt console error err stack res status send Something broke Keep your packages up to date Regularly update the packages you ve installed via NPM This will ensure you have the latest features and security patches You can update all packages to their latest version by running npm update in your terminal Common Mistakes and How to Avoid ThemCallback Hell and How to Avoid It Callback hell also known as Pyramid of Doom is a situation where callbacks are nested within callbacks making the code hard to read and understand This is a common issue in Node js because it uses a lot of asynchronous operations fs readdir source function err files if err console log Error finding files err else files forEach function filename fileIndex console log filename To avoid callback hell you can use Promises or async await which are built into modern versions of JavaScript Here s how you can rewrite the above code using async await async function readDirectory source try const files await fs promises readdir source files forEach filename fileIndex gt console log filename catch err console log Error finding files err Error Handling Mistakes One of the most common mistakes is not handling errors properly or not handling them at all This can lead to unexpected application crashes Always use a catch with Promises or a try catch block with async await to handle errors async function readDirectory source try const files await fs promises readdir source catch err console error Error reading directory err Memory Leaks and How to Prevent Them Memory leaks can cause your Node js application to use increasing amounts of memory over time which can degrade performance and eventually cause the application to crash Common causes of memory leaks include global variables forgotten timers or callbacks and not closing database connections To avoid memory leaks make sure to clear callbacks close database connections and be careful with global variables Also use tools like Node js process memoryUsage and heapdump to monitor and debug memory usage let globalVar new Array e This will consume a lot of memory globalVar null Make sure to nullify the variable when you re done with it ConclusionAnd there you have it We ve taken a deep dive into the world of Node js NPM and Express the backbone of modern web development We ve covered everything from your first contact with Node js exploring modules and the NPM world creating servers with Express js creating dynamic HTML with templating defining RESTful routes understanding middleware handling errors and integrating with the database We ve also shared some tips and best practices for working with these tools and discussed common mistakes and how to avoid them As we wrap up here are a few final pieces of advice Keep Practicing The more you use Node js NPM and Express the more comfortable you ll become Try building different types of projects to gain a wide range of experiences Stay Up to Date These tools are constantly evolving so it s important to stay up to date with the latest features and best practices Follow the official documentation and blogs join relevant communities and don t be afraid to ask questions Learn by Doing Reading and understanding concepts are important but real learning happens when you start building Don t be afraid to get your hands dirty Don t Be Afraid of Errors Errors are your friends They guide you toward the right path Learn to read and understand them and you ll become a better developer Additional ResourcesI d like to leave you with some additional resources that you can use to further your learning These resources are highly recommended for anyone looking to deepen their understanding of these tools and modern web development in general Node js Official Documentation This is the official documentation for Node js It s comprehensive well organized and a great place to start if you re looking for detailed information on a specific topic Express js Official Documentation Similar to the Node js documentation the official Express js documentation is a fantastic resource for understanding the ins and outs of Express js NPM Official Documentation This is the official documentation for NPM It s a great place to learn more about how NPM works and how to use it effectively Mozilla Developer Network MDN MDN is a treasure trove of web development knowledge It s not specific to Node js NPM or Express but it s a great resource for understanding web development concepts in general Stack Overflow Stack Overflow is a community of developers helping each other solve coding problems It s a great place to ask questions and learn from others experiences Node School Node School offers interactive tutorials for Node js NPM and many other related topics It s a great way to learn by doing Express js GitHub Repository Looking at the source code of a library or framework can be a great way to understand how it works under the hood The Express js GitHub repository is open source and available for anyone to explore	2023-08-13 13:04:30
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ニュース	Newsweek	ショー文化の本場を沸かす「ヨーヨーアーティスト」Naotoが示した夢のかなえ方	https://www.newsweekjapan.jp/stories/world/2023/08/post-102409.php	でも、世界を舞台に活躍する「ヨーヨーアーティスト」のNaotoは、好きな仕事をしながら夢を追いかけている人だ。	2023-08-13 22:15:00