이제 Express에 관한 내용을 알았으니, Windows, Linux (Ubuntu), 그리고 macOS 에서의 Node/Express 개발 환경을 설정하고 테스트하는 법을 보여드리겠습니다. 사용중인 운영 체제가 무엇이든 간에, 이 글은 당신에게 Express 앱 개발을 시작할 수 있도록 필요한 내용을 제공합니다.
| 전제 조건: | 터미널 혹은 명령어 창을 여는 방법. 당신의 개발 컴퓨터의 운영 체제에 소프트웨어 패키지를 설치하는 방법을 알고 있어야 합니다. |
|---|---|
| 목표: | 당신의 컴퓨터에 Express (X.XX) 을 위한 개발 환경을 설치하는 것. |
Node와 Express를 통해 웹앱 개발을 한결 수월하게 할 수 있습니다. 이 섹션에서는 어떤 도구들이 필요한지, Ubuntu, macOS, 그리고 Windows에서 어떻게 Node와 Express를 설치하는지, 마지막으로, 설치 후 어떻게 테스트해볼 수 있는지 살펴볼 것입니다.
Express개발환경은 Nodejs의 설치, NPM 패키지 매니저, 그리고 (선택적) 로컬 컴퓨터의 Express Application Generator를 포함합니다.
Node and the NPM package manager are installed together from prepared binary packages, installers, operating system package managers or from source (as shown in the following sections). Express is then installed by NPM as a dependency of your individual Express web applications (along with other libraries like template engines, database drivers, authentication middleware, middleware to serve static files, etc.)
NPM can also be used to (globally) install the Express Application Generator, a handy tool for creating skeleton Express web apps that follow the MVC pattern. The application generator is optional because you don't need to use this tool to create apps that use Express, or construct Express apps that have the same architectural layout or dependencies. We'll be using it though, because it makes getting started a lot easier, and promotes a modular application structure.
Note: Unlike for some other web frameworks, the development environment does not include a separate development web server. In Node/Express a web application creates and runs its own web server!
There are other peripheral tools that are part of a typical development environment, including text editors or IDEs for editing code, and source control management tools like Git for safely managing different versions of your code. We are assuming that you've already got these sorts of tools installed (in particular a text editor).
Node can be run on Windows, macOS, many "flavours" of Linux, Docker, etc. (there is a full list on the nodejs Downloads page). Almost any personal computer should have the necessary performance to run Node during development. Express is run in a Node environment, and hence can run on any platform that runs Node.
이 기사에서는 Windows, macOS, 그리고 Ubuntu Linux에서의 설치방법을 안내해드리고 있습니다.
There are many releases of Node — newer releases contain bug fixes, support for more recent versions of ECMAScript (JavaScript) standards, and improvements to the Node APIs.
Generally you should use the most recent LTS (long-term supported) release as this will be more stable than the "current" release while still having relatively recent features (and is still being actively maintained). You should use the Current release if you need a feature that is not present in the LTS version.
For Express you should always use the latest version.
Other dependencies, such as database drivers, template engines, authentication engines, etc. are part of the application, and are imported into the application environment using the NPM package manager. We'll discuss them in later app-specific articles.
Express 를 사용하기 위해서 우선 운영체제에 Nodejs와 Node Package Manager (NPM)를 설치해야 합니다. The following sections explain the easiest way to install the Long Term Supported (LTS) version of Nodejs on Ubuntu Linux 16.04, macOS, and Windows 10.
Tip: The sections below show the easiest way to install Node and NPM on our target OS platforms. If you're using another OS or just want to see some of the other approaches for the current platforms then see Installing Node.js via package manager (nodejs.org).
Node와 NPM을 설치하는 것은 간단합니다:
The easiest way to install the most recent LTS version of Node 10.x is to use the package manager to get it from the Ubuntu binary distributions repository. This can be done very simply by running the following two commands on your terminal:
curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash - sudo apt-get install -y nodejs
Warning: Don't install directly from the normal Ubuntu repositories because they contain very old versions of node.
The easiest way to test that node is installed is to run the "version" command in your terminal/command prompt and check that a version string is returned:
>node -v v10.15.1
The Nodejs package manager NPM should also have been installed, and can be tested in the same way:
>npm -v 6.4.1
As a slightly more exciting test let's create a very basic "pure node" server that simply prints out "Hello World" in the browser when you visit the correct URL in your browser:
//Load HTTP module
const http = require("http");
const hostname = '127.0.0.1';
const port = 3000;
//Create HTTP server and listen on port 3000 for requests
const server = http.createServer((req, res) => {
//Set the response HTTP header with HTTP status and Content type
res.statusCode = 200;
res.setHeader('Content-Type', 'text/plain');
res.end('Hello World\n');
});
//listen for request on port 3000, and as a callback function have the port listened on logged
server.listen(port, hostname, () => {
console.log(`Server running at http://${hostname}:${port}/`);
});
The code imports the "http" module and uses it to create a server (createServer()) that listens for HTTP requests on port 3000. The script then prints a message to the console about what browser URL you can use to test the server. The createServer() function takes as an argument a callback function that will be invoked when an HTTP request is received — this simply returns a response with an HTTP status code of 200 ("OK") and the plain text "Hello World".
Note: Don't worry if you don't understand exactly what this code is doing yet! We'll explain our code in greater detail once we start using Express!
hellonode.js file in your command prompt, and calling node along with the script name, like so:
>node hellonode.js Server running at http://127.0.0.1:3000/
Next to Node itself, NPM is the most important tool for working with Node applications. NPM is used to fetch any packages (JavaScript libraries) that an application needs for development, testing, and/or production, and may also be used to run tests and tools used in the development process.
Note: From Node's perspective, Express is just another package that you need to install using NPM and then require in your own code.
You can manually use NPM to separately fetch each needed package. Typically we instead manage dependencies using a plain-text definition file named package.json. This file lists all the dependencies for a specific JavaScript "package", including the package's name, version, description, initial file to execute, production dependencies, development dependencies, versions of Node it can work with, etc. The package.json file should contain everything NPM needs to fetch and run your application (if you were writing a reusable library you could use this definition to upload your package to the npm respository and make it available for other users).
The following steps show how you can use NPM to download a package, save it into the project dependencies, and then require it in a Node application.
Note: Here we show the instructions to fetch and install the Express package. Later on we'll show how this package, and others, are already specified for us using the Express Application Generator. This section is provided because it is useful to understand how NPM works and what is being created by the application generator.
mkdir myapp cd myapp
init command to create a package.json file for your application. This command prompts you for a number of things, including the name and version of your application and the name of the initial entry point file (by default this is index.js). For now, just accept the defaults:
npm init
If you display the package.json file (cat package.json), you will see the defaults that you accepted, ending with the license.
{
"name": "myapp",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1"
},
"author": "",
"license": "ISC"
}
myapp directory and save it in the dependencies list of your package.json filenpm install express
The dependencies section of your package.json will now appear at the end of the package.json file and will include Express.
{
"name": "myapp",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1"
},
"author": "",
"license": "ISC",
"dependencies": {
"express": "^4.16.4"
}
}
require() function in your index.js file to include it in your application. Create this file now, in the root of the "myapp" application directory, and give it the following contents:
const express = require('express')
const app = express();
app.get('/', (req, res) => {
res.send('Hello World!')
});
app.listen(8000, () => {
console.log('Example app listening on port 8000!')
});
This code shows a minimal "HelloWorld" Express web application. This imports the "express" module using require() and uses it to create a server (app) that listens for HTTP requests on port 8000 and prints a message to the console explaining what browser URL you can use to test the server. The app.get() function only responds to HTTP GET requests with the specified URL path ('/'), in this case by calling a function to send our Hello World! message.
>node index.js Example app listening on port 8000
If a dependency is only used during development, you should instead save it as a "development dependency" (so that your package users don't have to install it in production). For example, to use the popular JavaScript Linting tool eslint you would call NPM as shown:
npm install eslint --save-devThe following entry would then be added to your application's package.json:
"devDependencies": {
"eslint": "^4.12.1"
}
Note: "Linters" are tools that perform static analysis on software in order to recognise and report adherence/non-adherance to some set of coding best practice.
In addition to defining and fetching dependencies you can also define named scripts in your package.json files and call NPM to execute them with the run-script command. This approach is commonly used to automate running tests and parts of the development or build toolchain (e.g., running tools to minify JavaScript, shrink images, LINT/analyse your code, etc).
For example, to define a script to run the eslint development dependency that we specified in the previous section we might add the following script block to our package.json file (assuming that our application source is in a folder /src/js):
"scripts": {
...
"lint": "eslint src/js"
...
}
To explain a little further, eslint src/js is a command that we could enter in our terminal/command line to run eslint on JavaScript files contained in the src/js directory inside our app directory. Including the above inside our app's package.json file provides a shortcut for this command — lint.
We would then be able to run eslint using NPM by calling:
npm run-script lint
# OR (using the alias)
npm run lint
This example may not look any shorter than the original command, but you can include much bigger commands inside your npm scripts, including chains of multiple commands. You could identify a single npm script that runs all your tests at once.
The Express Application Generator tool generates an Express application "skeleton". Install the generator using NPM as shown (the -g flag installs the tool globally so that you can call it from anywhere):
npm install express-generator -gTo create an Express app named "helloworld" with the default settings, navigate to where you want to create it and run the app as shown:
express helloworld
Note: You can also specify the template library to use and a number of other settings. Use the help command to see all the options:
express --help
NPM will create the new Express app in a sub folder of your current location, displaying build progress on the console. On completion, the tool will display the commands you need to enter to install the Node dependencies and start the app.
The new app will have a package.json file in its root directory. You can open this to see what dependencies are installed, including Express and the template library Jade:
{
"name": "helloworld",
"version": "0.0.0",
"private": true,
"scripts": {
"start": "node ./bin/www"
},
"dependencies": {
"cookie-parser": "~1.4.3",
"debug": "~2.6.9",
"express": "~4.16.0",
"http-errors": "~1.6.2",
"jade": "~1.11.0",
"morgan": "~1.9.0"
}
}
Install all the dependencies for the helloworld app using NPM as shown:
cd helloworld npm install
Then run the app (the commands are slightly different for Windows and Linux/macOS), as shown below:
# Run the helloworld on Windows with Command Prompt SET DEBUG=helloworld:* & npm start # Run the helloworld on Windows with PowerShell SET DEBUG=helloworld:* | npm start # Run helloworld on Linux/macOS DEBUG=helloworld:* npm start
The DEBUG command creates useful logging, resulting in an output like that shown below.
>SET DEBUG=helloworld:* & npm start > helloworld@0.0.0 start D:\Github\expresstests\helloworld > node ./bin/www helloworld:server Listening on port 3000 +0ms
Open a browser and navigate to http://127.0.0.1:3000/ to see the default Express welcome page.
We'll talk more about the generated app when we get to the article on generating a skeleton application.
You now have a Node development environment up and running on your computer that can be used for creating Express web applications. You've also seen how NPM can be used to import Express into an application, and also how you can create applications using the Express Application Generator tool and then run them.
In the next article we start working through a tutorial to build a complete web application using this environment and associated tools.
{{PreviousMenuNext("Learn/Server-side/Express_Nodejs/Introduction", "Learn/Server-side/Express_Nodejs/Tutorial_local_library_website", "Learn/Server-side/Express_Nodejs")}}