Install Composer in China with Packagist Mirror

This command installs Composer and configures it to use the China mirror of Packagist, which can improve download speeds for users located in China.

'RUN curl --silent --show-error https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
&& composer config -g repo.packagist composer https://packagist.phpcomposer.com'

The command uses cURL to download the Composer installer from 'https://getcomposer.org/installer' and then pipes it into the PHP interpreter to run it. The '--install-dir=/usr/local/bin' option specifies the directory where Composer should be installed, and the '--filename=composer' option sets the name of the executable file that will be created.

After installing Composer, the command runs 'composer config' to set the global configuration option 'repo.packagist' to the URL of the China mirror of Packagist. This tells Composer to use the mirror as the default package repository when installing packages.