CODEWITHSUNDEEP
ruby
sanar
sanar

Reputation: 447

Convert string into hash in ruby

I have a string like this "{ssl:true,sslAllowInvalidCertificates:true}"

(please note that the string can contain any no. of key/value pairs)

I want to convert this into hash, in Ruby, like this:

{ssl:true,sslAllowInvalidCertificates:true}

(Please note that the output is to be exactly similar to the above. It should not be in 'generic' hash notation like

{"ssl" => "true","sslAllowInvalidCertificates" => "true"}

The MongoDB client library can recognize the option only if it is exactly same as per requirement, else throws error.

How to do this in ruby?

TIA!

Upvotes: 1

Views: 4071

Answers (2)

Todd A. Jacobs
Todd A. Jacobs

Reputation: 84343

TL;DR

To convert your String into a Hash, you either have to parse it yourself, or call Kernel#eval on it. Either way, your real issue seems to be round-tripping this back to a string in your expected format. One way to do that is to re-open the Hash class and add a custom output method, rather than relying on the Hash#to_s method aliased to Hash#inspect.

String to Hash

If you trust the data source and have some mechanism to sanitize or check the String for potential arbitrary code execution, #eval is certainly the easiest thing you can do. I'd personally add a tiny bit of safety by making sure the String isn't tainted first, though. For example:

str = "{ssl:true,sslAllowInvalidCertificates:true}"

raise "string tainted: #{str}" if str.tainted?
hsh = eval str
#=> {:ssl=>true, :sslAllowInvalidCertificates=>true}

However, if you don't trust the source or structure of your String, you can parse and validate the information yourself using some variant of the following as a starting point:

hsh = Hash[str.scan(/\w+/).each_slice(2).to_a]
#=> {:ssl=>true, :sslAllowInvalidCertificates=>true}

Hash to Custom String

If you then want to dump it back out to your custom format as a String, you can monkeypatch the Hash class or add a singleton method to a given Hash instance to provide a #to_mongo method. For example:

class Hash
  def to_mongo
    str = self.map { |k, v| '%s:%s' % [k, v] }.join ?,
    '{%s}' % str
  end
end

Calling this method on your Hash instance will yield the results you seem to want:

hsh.to_mongo
#=> "{ssl:true,sslAllowInvalidCertificates:true}"

Upvotes: 2

Joshua Pereira
Joshua Pereira

Reputation: 321

It seems there is some confusion surrounding the fat arrow syntax for hashes in ruby. You should be able to run eval on the string to generate the following hash:

{:ssl=>true, :sslAllowInvalidCertificates=>true}

You mention that the output cannot be in "generic" hash notation, which I assume is referring to the fat arrow notation used in your example.

Since Ruby 1.9, a new syntax can be used to create a hash

{foo: "bar"}

rather than the previous

{:foo => "bar"}

Interactive ruby consoles, such as irb and pry, try to print human friendly strings for the hash. Creating a hash with either of the two previous syntaxes will produce the same result in the console:

{:foo=>"bar"}

However, in memory, both of the objects are equivalent.

(There is the caveat that your "generic" hash example uses strings as keys. If that's what you're referring to, you can call #symbolize_keys on the hash)

Upvotes: 1

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