PHP7 : install ext-dom issue - laravel

Question

I'm running laravel 5.4 on Ubuntu 16.04 server with PHP7. trying to install cviebrock/eloquent-sluggable package throw some error:
pish#let:/home/sherk/ftp/www$ sudo composer require cviebrock/eloquent-sluggable
Do not run Composer as root/super user! See https://getcomposer.org/root for details
Using version ^4.2 for cviebrock/eloquent-sluggable
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- phpunit/php-code-coverage 4.0.7 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/php-code-coverage 4.0.7 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- Installation request for phpunit/php-code-coverage (installed at 4.0.7) -> satisfiable by phpunit/php-code-coverage[4.0.7].
To enable extensions, verify that they are enabled in those .ini files:
- /etc/php/7.0/cli/php.ini
- /etc/php/7.0/cli/conf.d/10-mysqlnd.ini
- /etc/php/7.0/cli/conf.d/10-opcache.ini
- /etc/php/7.0/cli/conf.d/10-pdo.ini
- /etc/php/7.0/cli/conf.d/20-calendar.ini
- /etc/php/7.0/cli/conf.d/20-ctype.ini
- /etc/php/7.0/cli/conf.d/20-exif.ini
- /etc/php/7.0/cli/conf.d/20-fileinfo.ini
- /etc/php/7.0/cli/conf.d/20-ftp.ini
- /etc/php/7.0/cli/conf.d/20-gd.ini
- /etc/php/7.0/cli/conf.d/20-gettext.ini
- /etc/php/7.0/cli/conf.d/20-iconv.ini
- /etc/php/7.0/cli/conf.d/20-json.ini
- /etc/php/7.0/cli/conf.d/20-mbstring.ini
- /etc/php/7.0/cli/conf.d/20-mcrypt.ini
- /etc/php/7.0/cli/conf.d/20-mysqli.ini
- /etc/php/7.0/cli/conf.d/20-pdo_mysql.ini
- /etc/php/7.0/cli/conf.d/20-phar.ini
- /etc/php/7.0/cli/conf.d/20-posix.ini
- /etc/php/7.0/cli/conf.d/20-readline.ini
- /etc/php/7.0/cli/conf.d/20-shmop.ini
- /etc/php/7.0/cli/conf.d/20-sockets.ini
- /etc/php/7.0/cli/conf.d/20-sysvmsg.ini
- /etc/php/7.0/cli/conf.d/20-sysvsem.ini
- /etc/php/7.0/cli/conf.d/20-sysvshm.ini
- /etc/php/7.0/cli/conf.d/20-tokenizer.ini
You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.
Installation failed, reverting ./composer.json to its original content.
I have no problem installing this package on local version of the app .

Answer 1

First of all, read the warning! It says do not run composer as root!
Secondly, you're probably using Xammp on your local which has the required php libraries as default.
But in your server you're missing ext-dom. php-xml has all the related packages you need. So, you can simply install it by running:
sudo apt-get update
sudo apt install php-xml
Most likely you are missing mbstring too. If you get the error, install this package as well with:
sudo apt-get install php-mbstring
Then run:
composer update
composer require cviebrock/eloquent-sluggable

Answer 2

sudo apt install php-xml will work but the thing is it will download the plugin for the latest PHP version.
If your PHP version is not the latest, then you can add version in it:
# PHP 7.1
sudo apt install php7.1-xml
# PHP 7.2:
sudo apt install php7.2-xml
# PHP 7.3
sudo apt install php7.3-xml
# PHP 7.4
sudo apt install php7.4-xml
# PHP 8
sudo apt install php-xml

Answer 3

For CentOS, RHEL, Fedora:
$ yum search php-xml
============================================================================================================ N/S matched: php-xml ============================================================================================================
php-xml.x86_64 : A module for PHP applications which use XML
php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php-xmlseclibs.noarch : PHP library for XML Security
php54-php-xml.x86_64 : A module for PHP applications which use XML
php54-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php55-php-xml.x86_64 : A module for PHP applications which use XML
php55-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php56-php-xml.x86_64 : A module for PHP applications which use XML
php56-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php70-php-xml.x86_64 : A module for PHP applications which use XML
php70-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php71-php-xml.x86_64 : A module for PHP applications which use XML
php71-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php72-php-xml.x86_64 : A module for PHP applications which use XML
php72-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php73-php-xml.x86_64 : A module for PHP applications which use XML
php73-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
Then select the php-xml version matching your php version:
# php -v
PHP 7.2.11 (cli) (built: Oct 10 2018 10:00:29) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
# sudo yum install -y php72-php-xml.x86_64

Answer 4

you need just update your local composer file:
first you need remove "composer.lock" file from you app
then, exec in your bash:
composer update --ignore-platform-req=ext-curl
so try again
composer require cviebrock/eloquent-sluggable