前言

今天在使用 composer 安装一个插件库的时候报错，看错误信息是缓存的字节大小限制和超时导致的。
对于不熟悉 composer 的 phper 一定要去了解一下，为什么一定？百度会有很多人告诉你答案。
附上composer中文文档连接：composer 中文文档

错误信息

Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 7 installs, 0 updates, 0 removals
  - Installing phpseclib/phpseclib (2.0.23): Downloading (45%)
Downloading (25%)
Downloading (10%)    Failed to download phpseclib/phpseclib from dist: Content-Length mismatch, received 30804 bytes out of the expected 264036
    Now trying to download from source
  - Installing phpseclib/phpseclib (2.0.23): Cloning c78eb5058d


  [Symfony\Component\Process\Exception\ProcessTimedOutException]
  The process "git clone --no-checkout "https://github.com/phpseclib/phpseclib.git" "E:\workspace\elastic_search\vendor\phpseclib\phpseclib" 
&& cd /D "E:\workspace\elastic_search\vendor\phpseclib\phpseclib" 
&& git remote add composer "https://github.com/phpseclib/phpseclib.git" 
&& git fetch composer" exceeded the timeout of 300 seconds.

一般跟超时有关的就是源的问题，这里需要更换一下源地址就好了

解决方法

1. 更换阿里云的 composer 源（亲测可用）

composer config repo.packagist composer https://mirrors.aliyun.com/composer/

repo 是 repositories 的简写方式
上面的命令值针对当前的项目有效，如果需要设置全局的在config后面加 -g 或 --global

注意：
   如果是只是因为超过缓存的大小，那只需要将缓存大小修改一下就好了
   修改命令：composer config cache-files-maxsize 800MiB

参考

• 【已解决】Content-Length mismatch, received 15988 bytes out of the 问题
• composer Content-Length mismatch