Accessing string in database without adding escape characters

Question

I have the following:

create_table "events", options: "ENGINE=InnoDB DEFAULT CHARSET=latin1", force: :cascade do |t|
  t.string "meta_data"
end

When I open up Valentina Studio and look at the events table I can see one record:

ID           meta_data      
1         {"action"=>"bla"}

When I call Event.last.meta_data I receive the following string:

"{\"action\"=>\"bla\"}

How can I get this string value without the escape characters? I've tried deep transforming and simply gsubbing but neither of these feel like I'm doing it right..

Thanks in advance

Tom Lord · Accepted Answer · 2019-05-13 09:52:13Z

3

There aren't any escape characters.

What you're looking at is the representation of the string when inspected on the console.

Consider the following:

irb(main):001:0> x = '"hello"'
=> "\"hello\""
irb(main):002:0> puts x
"hello"

The string does not contain any backslashes. But when inspecting it, backslashes must be present in order to distinguish "end of string" vs "quotation mark, inside the string".

answered May 13, 2019 at 9:52

Tom Lord

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5 Comments

Mark Over a year ago

Does that mean when I do calculations involving the string there will be no escape characters present?

Tom Lord Over a year ago

There aren't any escape characters present.

Tom Lord Over a year ago

Try using puts, to print the string to the console.

Tom Lord Over a year ago

For another example, suppose you have x = "\n". When inspecting the value, you see \n displayed literally. But when printing it, you see this is displayed "normally" (as a new line). Inspecting strings is a much more convenient way of being able to tell, unambiguously, exactly what the real value is.

Mark Over a year ago

Yup - I can see now you need some way to distinguish quote marks included in the string vs quote marks denoting the start of the string - thanks again

Mark · Accepted Answer · 2019-05-13 09:52:19Z

0

The least ugly way I can do this is:

JSON.parse(string.gsub("=>", ":").gsub(":nil,", ":null,"))

If anyone has a less ugly way please let me know

answered May 13, 2019 at 9:52

Mark

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