Ruby-mysql 问题 - 尝试为 Ruby 使用 mysql 模块时出错

Question

我正在使用 Ruby v2.0 并且我正在使用来自这里的 Ruby-mysql v2.9.14 连接器：https://rubygems.org/gems/ruby-mysql

我在运行此代码时遇到了一些错误：

require 'mysql'

begin
  connection = Mysql.new 'localhost', 'root', 'root'
  connection.list_dbs.each do |db|
    puts db
  end

rescue Mysql::Error => e
  puts e.errno
  puts e.error

ensure
  connection.close if connection
end

错误：

No such file or directory - "/tmp/mysql.sock" (Errno::ENOENT)
from /Library/Ruby/Gems/2.0.0/gems/ruby-mysql-2.9.14/lib/mysql/protocol.rb:150:in `new'
from /Library/Ruby/Gems/2.0.0/gems/ruby-mysql-2.9.14/lib/mysql/protocol.rb:150:in `block in initialize'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/timeout.rb:52:in `timeout'
from /Library/Ruby/Gems/2.0.0/gems/ruby-mysql-2.9.14/lib/mysql/protocol.rb:147:in `initialize'
from /Library/Ruby/Gems/2.0.0/gems/ruby-mysql-2.9.14/lib/mysql.rb:115:in `new'
from /Library/Ruby/Gems/2.0.0/gems/ruby-mysql-2.9.14/lib/mysql.rb:115:in `connect'
from /Library/Ruby/Gems/2.0.0/gems/ruby-mysql-2.9.14/lib/mysql.rb:50:in `new'
from /Users/Joakim/Google Drive/Skole/IT/Ruby/Modul 6/ruby-mysql.rb:4:in `<top (required)>'
from -e:1:in `load'
from -e:1:in `<main>'

我的老师告诉我是“司机”撞车了，但我不确定 - 对此我能做些什么吗？

Answer 1

驱动程序尝试通过套接字文件/tmp/mysql.sock 进行连接，该文件在您的系统中不可用（您可以检查该文件）。驱动程序假定您想通过套接字文件进行连接，因为您指定了localhost。

这是什么驱动does：

@host_info = (host.nil? || host == "localhost") ? 'Localhost via UNIX socket' : "#{host} via TCP/IP"

尝试将localhost 更改为127.0.0.1。

已编辑

好像你用的是mysql的自定义端口，8889，所以连接数据库的时候需要指定：

connection = Mysql.new 'localhost', 'root', 'root', nil, 8889

这是method definition 的sn-p：

  # Connect to mysqld.
  # @param [String / nil] host hostname mysqld running
  # @param [String / nil] user username to connect to mysqld
  # @param [String / nil] passwd password to connect to mysqld
  # @param [String / nil] db initial database name
  # @param [Integer / nil] port port number (used if host is not 'localhost' or nil)
  # @param [String / nil] socket socket file name (used if host is 'localhost' or nil)
  # @param [Integer / nil] flag connection flag. Mysql::CLIENT_* ORed
  # @return self
  def connect(host=nil, user=nil, passwd=nil, db=nil, port=nil, socket=nil, flag=0)