LAMP PHP configuration

OS: Ubuntu 17.10 (Artful Aardvark)

I have installed the LAMP stack and Laravel, and when I tried composer install in my Laravel application, I got the following errors.

- Installation request for phar-io/manifest 1.0.1 -> satisfiable by phar-io/manifest[1.0.1].
  - phar-io/manifest 1.0.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
Problem 2
  - Installation request for phpunit/php-code-coverage 5.2.2 -> satisfiable by phpunit/php-code-coverage[5.2.2].
  - phpunit/php-code-coverage 5.2.2 requires ext-dom * -> the requested PHP extension dom is missing from your system.
Problem 3
  - Installation request for phpunit/phpunit 6.4.3 -> satisfiable by phpunit/phpunit[6.4.3].
  - phpunit/phpunit 6.4.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
Problem 4
  - Installation request for theseer/tokenizer 1.1.0 -> satisfiable by theseer/tokenizer[1.1.0].
  - theseer/tokenizer 1.1.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.

To enable extensions, verify that they are enabled in your .ini files:
  - /etc/php/7.1/cli/php.ini
  - /etc/php/7.1/cli/conf.d/10-opcache.ini
  - /etc/php/7.1/cli/conf.d/10-pdo.ini
  - /etc/php/7.1/cli/conf.d/20-calendar.ini
  - /etc/php/7.1/cli/conf.d/20-ctype.ini
  - /etc/php/7.1/cli/conf.d/20-exif.ini
  - /etc/php/7.1/cli/conf.d/20-fileinfo.ini
  - /etc/php/7.1/cli/conf.d/20-ftp.ini
  - /etc/php/7.1/cli/conf.d/20-gettext.ini
  - /etc/php/7.1/cli/conf.d/20-iconv.ini
  - /etc/php/7.1/cli/conf.d/20-json.ini
  - /etc/php/7.1/cli/conf.d/20-mbstring.ini
  - /etc/php/7.1/cli/conf.d/20-pdo.ini
  - /etc/php/7.1/cli/conf.d/20-phar.ini
  - /etc/php/7.1/cli/conf.d/20-posix.ini
  - /etc/php/7.1/cli/conf.d/20-readline.ini
  - /etc/php/7.1/cli/conf.d/20-shmop.ini
  - /etc/php/7.1/cli/conf.d/20-sockets.ini
  - /etc/php/7.1/cli/conf.d/20-sysvmsg.ini
  - /etc/php/7.1/cli/conf.d/20-sysvsem.ini
  - /etc/php/7.1/cli/conf.d/20-sysvshm.ini
  - /etc/php/7.1/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.

I have rechecked the files, all extensions are enabled and they are located in the /usr/lib/php/20160303 folder.

Answer

Sometimes the problem is the php-xml extension.

Try:

sudo apt-get install php-xml