背景情况 #

我在MySQL中创建了采用caching_sha2_password认证方式的用户，执行的SQL语句如下：

CREATE USER '[user]'@'[host]' IDENTIFIED WITH caching_sha2_password BY '[password]';
GRANT INSERT, SELECT ON [db].[table] TO '[user]'@'[host]';

我特意没有使用mysql_native_password，因为该认证方式在MySQL 8.4中默认禁用，且在MySQL 9.0中已被移除。

查阅官方文档时，我看到了两处相关说明：

• PHP 8.4「Choosing a library」部分的编译建议：

  // Recommended, compiles with mysqlnd
  $ ./configure --with-mysqli=mysqlnd --with-pdo-mysql=mysqlnd
  // Alternatively recommended, compiles with mysqlnd
  $ ./configure --with-mysqli --with-pdo-mysql
  // Not recommended, compiles with libmysqlclient
  $ ./configure --with-mysqli=/path/to/mysql_config --with-pdo-mysql=/path/to/mysql_config

• MySQL 8.4「8.4.1.2 Caching SHA-2 Pluggable Authentication」部分的说明：

  Installing SHA-2 Pluggable Authentication
  The caching_sha2_password plugin exists in server and client forms:

  • The server-side plugin is built into the server, need not be loaded explicitly, and cannot be disabled by unloading it.
  • The client-side plugin is built into the libmysqlclient client library and is available to any program linked against libmysqlclient.
    The server-side plugin uses the sha2_cache_cleaner audit plugin as a helper to perform password cache management. sha2_cache_cleaner, like caching_sha2_password, is built in and need not be installed.

当前遇到的问题 #

我当前编译PHP 8.4使用的配置命令是：

./configure \
--prefix=$path_to_php_bin \
--with-apxs=/usr/local/apache2/bin/apxs \
--enable-mbstring \
--with-mysqli \
--with-mysql=mysqlnd \
--with-mysqli=mysqlnd \
--with-pdo-mysql=mysqlnd \
--with-iconv=$(brew --prefix libiconv) \
--enable-fpm

但当我在网页中尝试创建mysqli连接时，触发了致命错误：

Fatal error: Uncaught mysqli_sql_exception: The server requested authentication method unknown to the client [caching_sha2_password] in [path_to_global_php_commands_include_file]:201
#0 [path_to_global_php_commands_include_file](201): mysqli_connect([host], [user], [password], [db])
#1 [path_to_mysqli_connect_variables_file](10): connectDBi([host], [user], [password], [db])
#2 [path_to_php/html_header_file](12):include('[path_to_mysqli_connect_variables_file]')
#3 [path_to_website_index_file](3): include('[path_to_php/html_header_file]')
#4 {main} thrown in [path_to_global_php_include_commands_file] on line 201

我猜测这个错误是因为我没有使用libmysqlclient编译PHP导致的——毕竟PHP文档明确不推荐使用libmysqlclient，但MySQL文档又指出需要链接该库才能使用caching_sha2_password的客户端插件。

我的疑问 #

• 如果要在MySQL 8.*环境下使用caching_sha2_password，必须用libmysqlclient编译PHP 8.*吗？那为什么PHP官方会推荐不这么做？
• 有没有比用libmysqlclient编译PHP 8.*更好的方式来启用caching_sha2_password支持？
• 如果我必须用libmysqlclient编译，使用命令：$ ./configure --with-mysqli=/path/to/mysql_config --with-pdo-mysql=/path/to/mysql_config，那my.conf里需要添加什么配置才能让PHP编译后有效支持caching_sha2_password？
• 在--with-mysqli=...和--with-pdo-mysql=...里的mysql_config指的是my.conf吗？

麻烦各位大佬帮忙解答，谢谢！