Ruby:将转义字符串写入 YAML

Question

以下...

require 'yaml'
test = "I'm a b&d string"
File.open('test.yaml', 'w') do |out|
  out.write(test.to_yaml)
end

...输出...

--- this is a b&d string

如何让它输出

--- 'this is a b&d string'

???

Answer 1

如果你想在 YAML 中存储转义字符串，在将其转换为 YAML 之前使用 #inspect 对其进行转义:

irb> require 'yaml'
=> true
irb> str = %{This string's a little complicated, but it "does the job" (man, I hate scare quotes)}
=> "This string's a little complicated, but it \"does the job\" (man, I hate scare quotes)"
irb> puts str
This string's a little complicated, but it "does the job" (man, I hate scare quotes)
=> nil
irb> puts str.inspect
"This string's a little complicated, but it \"does the job\" (man, I hate scare quotes)"
=> nil
irb> puts str.to_yaml
--- This string's a little complicated, but it "does the job" (man, I hate scare quotes)
=> nil
irb> puts str.inspect.to_yaml
--- "\"This string's a little complicated, but it \\\"does the job\\\" (man, I hate scare quotes)\""
=> nil

除非必须，否则 YAML 不会引用字符串。如果字符串包含未加引号存储时会遗漏的内容，它会引用字符串 - 例如周围的引号字符或尾随或前导空格:

irb> puts (str + " ").to_yaml
--- "This string's a little complicated, but it \"does the job\" (man, I hate scare quotes) "
=> nil
irb> puts %{"#{str}"}.to_yaml
--- "\"This string's a little complicated, but it \"does the job\" (man, I hate scare quotes)\""
=> nil
irb> puts (" " + str).to_yaml
--- " This string's a little complicated, but it \"does the job\" (man, I hate scare quotes)"
=> nil

但是，作为 YAML 使用者，字符串是否被引号对您来说不重要。你永远不应该自己解析 YAML 文本——把它留给图书馆。如果您需要 YAML 文件中引用的字符串，我觉得这很糟糕。

无论您的字符串中是否包含“&”，YAML 都会保留该字符串:

irb> test = "I'm a b&d string"
=> "I'm a b&d string"
irb> YAML::load(YAML::dump(test))
=> "I'm a b&d string"
irb> YAML::load(YAML::dump(test)) == test
=> true