Installing Node

Installing NVM

NVM handles installing and managing node versions on the server.

Installation Script

Run the following command to download and install NVM version 0.39.7 into ~/.nvm/.

curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.7/install.sh | bash

Source .bashrc

NVM adds itself to the $PATH by modifying ~/.bashrc. Log out and in again so that the `nvm` command works. You should be able to check its version.

$ source ~/.nvm/nvm.sh
$ nvm --version
0.39.7
$ 

Installing Node

Now that nvm is installed, installing node is easy.

Choosing A Version

Go to https://nodejs.org/ and make a note of the version number of the latest LTS node version.

Install the specific node version with the command below. Replace 20.11.0 with the latest LTS version number.

nvm install 20.11.0

nvm install 16.20.2

Verify node is installed by checking the version.

$ node --version
20.11.0

Node is now installed in ~/.nvm/versions/node/v20.11.0/bin/node, where 20.11.0 is the version number installed.

Verify the install location with the `which` command.

$ which node
~/.nvm/versions/node/v20.11.0/bin/node

Testing Node

Let's try out a node script.

The Hello Node Script

Run a simple node test.

Create hello-world.js

#!/usr/bin/env node
console.log('Hello Node!')

Make It Executable

$ chmod +x hello-world.js

Execute It

$ ./hello-world.js
Hello Node!
$ 

Node & CGI

With node installed we can now generate dynamic web pages using the Common Gateway Interface (CGI).

The Hello CGI Script

Create the CGI script in the ~/cgi-bin/ folder.

~/cgi-bin/hello-world.js

#!/home/example_user/.nvm/versions/node/v20.11.0/bin/node
process.stdout.write('Content-Type: text/plain\n\n');
process.stdout.write('Hello World!\n);

Make It Executable

$ chmod +x ~/cgi-bin/hello-world.js

View The Webpage

Explanation

Notice that the CGI script uses the full path to the node binary in the shebang (#!). That is because the server has a different PATH environment variable that doesn't include the path to node. Try adding console.log(process.env); to the CGI script and looking at the PATH environment variable to see why #!/usr/bin/env node won't work in the CGI script.

The first lines written out are the HTTP headers. In this basic example we set one header, the content type, to text/plain.

The HTTP body comes after two newlines. The body is set to "Hello World!"

There is a lot to HTTP and I wouldn't suggest trying to implement everything yourself in a CGI script. There are many packages available that will help to parse requests and generate responses.