composer报错：
[ComposerDownloaderTransportException]
Content-Length mismatch, received 134399 bytes out of the expected 1798606
解决方法：（加载镜像）
阿里：composer config -g repo.packagist composer https://mirrors.aliyun.com/composer/
站点：https://developer.aliyun.com/composer
composer报错：
Installation failed, reverting ./composer.json to its original content. The following exception is caused by a lack of memory or swap, or not having swap configured Check https://getcomposer.org/doc/articles/troubleshooting.md#proc-open-fork-failed-errors for details
proc_open(): fork failed - Cannot allocate memory
解决方法：
/bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=1024
/sbin/mkswap /var/swap.1
/sbin/swapon /var/swap.1
第一行：创建一个 1G 大小的文件
第二行：格式化该文件
第三行：将该文件挂载至文件系统中。
效果，内存大了一些
