Ruby 和 mysql2：循环直到连接无错误

Question

上下文：我正在使用 mysql2 gem 在 Ruby 中编写一个简单的动态查询。

尝试：

#!/usr/local/bin/ruby
require "mysql2"

puts "Please enter the title of this Report:"
title = gets.chomp

Mysql2::Client.default_query_options.merge!(:as => :array)

puts "Please enter the host, username, password and database in order:"
hst = gets.chomp
user = gets.chomp
pass = gets.chomp
db = gets.chomp

begin
  mysql = Mysql2::Client.new(:host => hst, :username => user, :password => pass, :database => db)
rescue Mysql2::Error => e
    puts e.errno
    puts e.error
  retry
  puts "Error: please try again."
  puts "Enter the host, username, password and database:"
  hst = gets.chomp!
  user = gets.chomp!
  pass = gets.chomp!
  db = gets.chomp!
end

puts "Successfully accessed #{db}!"

注意：

rescue Mysql2::Error => e
    puts e.errno
    puts e.error

适用于 mysql gem，但是：

rescue Mysql2::StandardError => e
    puts e.errno
    puts e.error

不能与mysql2 gem 一起使用。

最后，终端报错：

iMac:workspace guy$ ruby File.rb
Please enter the title of this Report:
title
Please enter the host, username, password and database in order:
1.2.3.4
username15
password123
db_one
File.rb:19:in `rescue in <main>': uninitialized constant Mysql2::StandardError (NameError)
Did you mean?  StandardError
    from File.rb:17:in `<main>'

回答后编辑：将:host 保留为:hst 给了我以下错误：

2002
Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

Answer 1

mysql2 gem 定义了Mysql2::Error，而不是`Mysql2::StandardError。

你需要拯救Mysql2::Error

请参阅mysql2 Github source 了解更多信息。