执行命令：curl -sS https://getcomposer.org/installer | php
报错如下
Some settings on your machine make Composer unable to work properly.
Make sure that you fix the issues listed below and run this script again:
The openssl extension is missing, which means that secure HTTPS transfers are impossible.
If possible you should enable it or recompile php with --with-openssl
没有openssl扩展
cd php7.0/ext/openssl // 进入到openssl文件
phpize // 运行phpize
编译和安装
./configure --with-openssl --with-php-config=/usr/local/php/bin/php-config // 编译和安装
遇到报错：
configure: error: Cannot find OpenSSL‘s <evp.h>
缺少openssl相关的库，直接安装即可
yum install openssl openssl-devel
遇到“configure: error: mcrypt.h not found. Please reinstall libmcrypt”
提示比较明确，缺少libmcrypt，直接安装即可
yum install?libmcrypt
最后执行 make && make install
进入最后提示的目录 cp openssl.so /usr/local/php/include/php/ext
找到php.ini，在最后面添加如下内容： extension=openssl.so
重启 后查看扩展: php -m