2.23.13. Node.js

1. The request goes to the public server on port 80 or 443.
2. Based on the hostname, redirects to the socket of the desired site.
3. The application receives data over the socket, processes it, and returns a response.

1. Openup site settings.
2. Select your Node.js web server, select the version you want and save your changes:
3. Place application files in root directory site - download the files of the finished project or install using npm.
4. Add a script with the command start in package.json
5. Clickon "Restart" in Node.js settings.

npm - Node.js package manager.

Commands:

• npm -v — view the current version of npm.
• npm install package (или npm i package) — install the package. After installation, a subdirectory will appear node_moduleswhere the installed module will be located.
• npm uninstall package - package removal.

package.json — configuration file and npm package management.

Options:

• name (mandatory) — the name of the application in small Latin letters without spaces, symbols can be used to separate words - and _.
• version (mandatory) - the version of the application in the format x.x.x.
• description — application description.
• dependencies — section with information about all packages used by the application.

Team npm init - creates a file from scratch. All necessary data is requested before creation. At the end, you need to familiarize yourself with the contents of the future file and if everything is in order, enter yes. Note You can just click on all the questions Enter, then a file with standard content will be created.

Block "App status":

• "App status" - the current status of the Node.js service:
  • "Running" - the service is up and running.
  • "Stopped" — not started (for example, due to the lack of package.json) or stopped due to an error.
• "Command to run" — the presence of a script with a command start in file package.json:
  • "Present" - found.
  • "Missing" — not found.
• "Force restart" - service restart. Warning! You need to click after any file changes.
• "Forced stop" - stopping the service. The button is displayed only when the application is running.

Block "Main settings":

• The path to the socket.
• The name of an environment variable containing the path to the socket. Note Pushed to every application when it starts.
• Sample code that should be in an application to listen for site traffic.

Block "App start" - contains the command to be added to package.json to run the application (./index.js in the command - the path to the main application file, the file name can be anything):

Block "Your package.json" - shows the current content of the file package.json of root directory site (updated when opening or reloading the settings page):

If syntax errors are found in the file in the block, a notification will be displayed "File contains errors"... The presence of an error notification while the application is running means that the application was launched before the error appeared in the file.

Block "App logs" - displaying application logs in real time. Includes information that the application writes to the console while it is running.

1. Create in root directory site two files:
   1. Configuration file package.json:

      {
        "name": "node",
        "version": "1.0.0",
        "scripts": {
          "start": "node ./index.js"
        }
      }

   2. Application file index.js:

      const HTTP = require('http');
      const WebServer = HTTP.createServer((req, res) => {
          res.statusCode = 200;
          res.setHeader('Content-Type', 'text/plain');
          res.end('Hello, World!');
      });
      WebServer.listen(process.env.PORT, () => {
          console.log(`Server is running.`);
      });

2. Clickon "Restart" in Node.js settings.
3. Open the site in a browser. If everything is ok, you will see the text "Hello, World!".

1. Connect to hosting via SSH.
2. Go to root directory site with a command of the form:

   cd example.com/www

   Where example.com - Name of the site, www - its subdomain.

3. Initialize npm and install the express framework with the command:

   npm init && npm i express

4. Create in root directory site application file index.js:

   const express = require("express");
   const app = express();
    
   app.get("/", function(request, response){
       response.end("Hello from Express!");
   });
    
   app.listen(process.env.PORT);

5. Edit the file package.json and add a launch command of the form to it:

   "scripts": {
       "start": "node ./index.js"
   }

   Observe JSON syntax when adding a command!

   The command needs to be added not just to the end of the file, and following the standard JSON format syntax:

   • Section scripts should not be duplicated. If it is already in the file, add the command start there.
   • There must be a comma at the end of the previous line at the same nesting level.
   • The nesting order of the parentheses must be correct.
6. Clickon "Restart" in Node.js settings.
7. Open the site in a browser. If everything is ok, you will see the text "Hello from Express!".