解决Node.js mysql客户端不支持认证协议引发的“ER_NOT_SUPPORTED_AUTH_MODE”问题

起因

mysql模块（项目地址为https://github.com/mysqljs/mysql）是一个开源的、JavaScript编写的MySQL驱动，可以在Node.js应用中来操作MySQL。但在使用过程中，出现了“ER_NOT_SUPPORTED_AUTH_MODE”问题。

本文介绍了出现该问题的原因及解决方案。

报错信息

当我试图使用mysql模块来连接MySQL 8时，出现了如下错误信息：

D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\index.js:17
      throw error;
      ^

Error: ER_NOT_SUPPORTED_AUTH_MODE: Client does not support authentication protocol requested by server; consider upgrading MySQL client
    at Handshake.Sequence._packetToError (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\node_modules\mysql\lib\protocol\sequences\Sequence.js:47:14)
    at Handshake.ErrorPacket (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\node_modules\mysql\lib\protocol\sequences\Handshake.js:123:18)
    at Protocol._parsePacket (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\node_modules\mysql\lib\protocol\Protocol.js:291:23)
    at Parser._parsePacket (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\node_modules\mysql\lib\protocol\Parser.js:433:10)
    at Parser.write (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\node_modules\mysql\lib\protocol\Parser.js:43:10)
    at Protocol.write (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\node_modules\mysql\lib\protocol\Protocol.js:38:16)
    at Socket.<anonymous> (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\node_modules\mysql\lib\Connection.js:91:28)
    at Socket.<anonymous> (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\node_modules\mysql\lib\Connection.js:525:10)
    at Socket.emit (events.js:196:13)
    at addChunk (_stream_readable.js:290:12)
    --------------------
    at Protocol._enqueue (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\node_modules\mysql\lib\protocol\Protocol.js:144:48)
    at Protocol.handshake (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\node_modules\mysql\lib\protocol\Protocol.js:51:23)
    at Connection.connect (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\node_modules\mysql\lib\Connection.js:119:18)
    at Object.<anonymous> (D:\workspaceGithub\nodejs-book-samples\samples\mysql-demo\index.js:12:12)
    at Module._compile (internal/modules/cjs/loader.js:759:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:770:10)
    at Module.load (internal/modules/cjs/loader.js:628:32)
    at Function.Module._load (internal/modules/cjs/loader.js:555:12)
    at Function.Module.runMain (internal/modules/cjs/loader.js:826:10)
    at internal/main/run_main_module.js:17:11

出错原因

导致这个错误的原因是，目前，最新的mysql模块并未完全支持MySQL 8的“caching_sha2_password”加密方式，而“caching_sha2_password”在MySQL 8中是默认的加密方式。因此，下面的方式命令是默认已经使用了“caching_sha2_password”加密方式，该账号、密码无法在mysql模块中使用。

mysql> ALTER USER 'root'@'%' IDENTIFIED BY '123456';
Query OK, 0 rows affected (0.12 sec)

然后查看mysql的用户表

mysql> select host,user,plugin from user \G;
*************************** 1. row ***************************
  host: %
  user: root
plugin: caching_sha2_password
*************************** 2. row ***************************
  host: localhost
  user: mysql.infoschema
plugin: caching_sha2_password
*************************** 3. row ***************************
  host: localhost
  user: mysql.session
plugin: caching_sha2_password
*************************** 4. row ***************************
  host: localhost
  user: mysql.sys
plugin: caching_sha2_password
*************************** 5. row ***************************
  host: localhost
  user: root
plugin: caching_sha2_password
5 rows in set (0.00 sec)

解决方法

解决方法是从新修改用户root的密码，并指定mysql模块能够支持的加密方式：

mysql> ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY '123456';
Query OK, 0 rows affected (0.12 sec)

上述语句，显示指定了使用“mysql_native_password”的加密方式。这种方式是在mysql模块能够支持。

mysql> select host,user,plugin from user \G;
*************************** 1. row ***************************
  host: %
  user: root
plugin: mysql_native_password
*************************** 2. row ***************************
  host: localhost
  user: mysql.infoschema
plugin: caching_sha2_password
*************************** 3. row ***************************
  host: localhost
  user: mysql.session
plugin: caching_sha2_password
*************************** 4. row ***************************
  host: localhost
  user: mysql.sys
plugin: caching_sha2_password
*************************** 5. row ***************************
  host: localhost
  user: root
plugin: caching_sha2_password
5 rows in set (0.00 sec)

再此运行应用，可以看到如下的控制台输出信息：

$ node index.js

The result is:  RowDataPacket { user_id: 1, username: '老卫' }