composer安装使用和常见问题

php -r "copy('https://install.phpcomposer.com/installer', 'composer-setup.php');"
php composer-setup.php
php -r "unlink('composer-setup.php');"

copy(): Unable to find the wrapper "https"
Openssl

[Composer\Downloader\TransportException]
Your configuration does not allow connections to http://packagist.org/packa
ges.json. See https://getcomposer.org/doc/06-config.md#secure-http for deta
ils.
composer config -g secure-http false

错误

content-length mismatch
composer config -g repo.packagist composer https://packagist.phpcomposer.com