error install laravel v 5.4 with composer in ubuntu

Question

hey a get error when install laravel v-5.4

a get error this :

The " http://packagist.org/p/provider-2016%24e217873bdc8408956b33b1eb317ad1182d3a82fde9a746cc5e7def6135696f96.json " file could not be downloaded (HTTP/1.1 500 Internal Server Error) http://packagist.org could not be fully loaded, package information was loaded from the local cache and may be out of date Installing laravel/laravel (v5.5.0) - Installing laravel/laravel (v5.5.0): Loading from cache Created project in blog @php -r "file_exists('.env') || copy('.env.example', '.env');" Loading composer repositories with package information Updating dependencies (including require-dev)

Failed to decode response: zlib_decode(): data error Retrying with degraded mode, check https://getcomposer.org/doc/articles/troubleshooting. md#degraded-mode for more info Your requirements could not be resolved to an installable set of packages.

Problem 1
- phpunit/phpunit 6.4.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.4.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.3.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.3.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.2.4 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.2.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.2.2 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.2.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.2.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.1.4 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.1.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.1.2 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.1.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.1.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.9 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.8 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.7 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.6 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.5 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.4 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.2 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.13 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.12 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.11 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.10 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- phpunit/phpunit 6.0.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
- Installation request for phpunit/phpunit ~6.0 -> satisfiable by phpunit/phpunit[6.0.0, 6.0.1, 6.0.10, 6.0.11, 6.0.12, 6.0.13, 6.0.2, 6.0.3, 6.0.4, 6.0.5, 6.0.6, 6.0.7, 6.0.8, 6.0.9, 6.1.0, 6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.2.0, 6.2.1, 6.2.2, 6.2.3, 6.2.4, 6.3.0, 6.3.1, 6.4.0, 6.4.1].

please help me for finish this problem. I tried but but no result.

Answer 1

If you are using PHP 7 or later, you can install ext-dom by running the following command:

sudo apt-get install php7.0-xml // for PHP 7
sudo apt-get install php7.1-xml // for PHP 7