调用相关php向数据库查询或者添加，开发者工具里报PHP 500错误，怎么一回事？

Question

开源项目链接：https://github.com/jxj322991/...

本地设置：

二维码活码开源项目，本人使用的SQLyog+phpStudy，在本地测试时，可以正常访问主页，但是登录和注册时调用相关php向数据库查询或者添加，开发者工具里报PHP 500错误。

可正常访问主页，但登录和注册报错，就后续无法操作了，比如注册操作：

报500错误：

点开报错的register.php,显示空白：

custom.js是用来调用其他php的，

hosts和phpStudy的vhosts.conf都已设置：

登录和游客的调用login.php也是在custom.js中调用，同样是报500的错误，请问大佬们，我是哪里设定错了，该如何改正能正常运行？

Answer 1

500是服务端错误，也就是说执行PHP文件的时候报错了
这个错误有很多种可能，可能是你PHP语法有问题，也可能是连接Mysql失败了，也可能是文件操作没有权限...
常用的调试方法是打开报错信息或者工程有错误日志功能，分析错误信息
或者安装xdebug进行断点调试
最笨的方法是一行一行写die，手动写断点分析问题原因。

Answer 2

500 是服务器错误,也就是后端的错误,所以你可以检查一下代码或者在index.php 或者login.php第二行加上

ini_set("display_errors","On");
error_reporting(E_ALL);

两行代码

Answer 3

错误日志看不懂...
[09-Jul-2020 10:29:28 PRC] PHP Warning: mysqli_connect(): MySQL server has gone away in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:29:28 PRC] PHP Warning: mysqli_connect(): Error while reading greeting packet. PID=8248 in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:29:28 PRC] PHP Warning: mysqli_connect(): (HY000/2006): MySQL server has gone away in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:29:28 PRC] PHP Fatal error: Maximum execution time of 30 seconds exceeded in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:30:09 PRC] PHP Warning: mysqli_connect(): MySQL server has gone away in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:30:09 PRC] PHP Warning: mysqli_connect(): Error while reading greeting packet. PID=7636 in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:30:09 PRC] PHP Warning: mysqli_connect(): (HY000/2006): MySQL server has gone away in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:30:09 PRC] PHP Fatal error: Maximum execution time of 30 seconds exceeded in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:34:40 PRC] PHP Warning: mysqli_connect(): MySQL server has gone away in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:34:40 PRC] PHP Warning: mysqli_connect(): Error while reading greeting packet. PID=8248 in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:34:40 PRC] PHP Warning: mysqli_connect(): (HY000/2006): MySQL server has gone away in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:34:40 PRC] PHP Fatal error: Maximum execution time of 30 seconds exceeded in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:35:07 PRC] PHP Warning: mysqli_connect(): MySQL server has gone away in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:35:07 PRC] PHP Warning: mysqli_connect(): Error while reading greeting packet. PID=7636 in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:35:07 PRC] PHP Warning: mysqli_connect(): (HY000/2006): MySQL server has gone away in E:BoboCodewxhuomadistphpconn_sql.php on line 11
[09-Jul-2020 10:35:07 PRC] PHP Fatal error: Maximum execution time of 30 seconds exceeded in E:BoboCodewxhuomadistphpconn_sql.php on line 11