一、composer 更新提示 [Composer\Downloader\TransportException] Peer fingerprint did not match

出现这个问题可能是php版本问题，切换至PHP7.0版本看是否可行。如果不行，则重装composer

因为使用的 lnmp 装的系统，自带 composer，php -v 发现 cil 的版本是 5.4.
修改下 PHP 的 cil 版本，然后重新安装下 composer 就可以了.
https://blog.csdn.net/lmp5023/article/details/102755061

二、Composer update遇到 Content-Length mismatch, received 137675 bytes out of the expected 2367236

1、查看当前镜像源 composer config -l

2、上图可以看到使用的是国外镜像,此处要使用中国镜像源
composer config repo.packagist composer https://mirrors.aliyun.com/composer/

3、再次确认镜像源情况

三、composer报错版本太旧
提示黄色“Warning from https://repo.packagist.org: You are using an outdated version of Composer. Composer 2.0 is now available and you should upgrade. See https://getcomposer.org/2”

解决办法：

升级本地的composer版本

composer self-update
或
composer self-update -vvv

四、PHP安装TP6的composer install报Undefined index: process
解决办法：没有添加Swoole扩展
或者看黄色提示“The Process class relies on proc_open, which is not available on your PHP installation.”
需要打开php禁用的函数 proc_open

五、安装消息队列beanstalkd扩展方法

http://www.04007.cn/article/249.html

http://www.04007.cn/article/480.html

六、宝塔安装开启swoole扩展

https://blog.csdn.net/weixin_30652271/article/details/97671719

七、安装成功，黄色提示
Package mtdowling/cron-expression is abandoned, you should avoid using it. Use dragonmantank/cron-expression ins
tead.Package phpunit/php-token-stream is abandoned, you should avoid using it. No replacement was suggested.
Package phpunit/phpunit-mock-objects is abandoned, you should avoid using it. No replacement was suggested.

八、

Warning from https://repo.packagist.org: Support for Composer 1 is deprecated and some packages will not be available. You should upgrade to Composer 2. See https://blog.packagist.com/deprecating-composer-1-support/

原因：composer版本太低了

解决方法：升级composer

升级命令：composer self-update