How to URL encode a string in Ruby

Question

str = "\x12\x34\x56\x78\x9a\xbc\xde\xf1\x23\x45\x67\x89\xab\xcd\xef\x12\x34\x56\x78\x9a".force_encoding('ASCII-8BIT')
puts CGI.escape str


=> "%124Vx%9A%BC%DE%F1%23Eg%89%AB%CD%EF%124Vx%9A"

Nowadays, you should use ERB::Util.url_encode or CGI.escape. The primary difference between them is their handling of spaces:

>> ERB::Util.url_encode("foo/bar? baz&")
=> "foo%2Fbar%3F%20baz%26"

>> CGI.escape("foo/bar? baz&")
=> "foo%2Fbar%3F+baz%26"

CGI.escape follows the CGI/HTML forms spec and gives you an application/x-www-form-urlencoded string, which requires spaces be escaped to +, whereas ERB::Util.url_encode follows RFC 3986, which requires them to be encoded as %20.

See "https://stackoverflow.com/questions/2824126/whats-the-difference-between-uri-escape-and-cgi-escape/13059657#13059657" for more discussion.

str = "\x12\x34\x56\x78\x9a\xbc\xde\xf1\x23\x45\x67\x89\xab\xcd\xef\x12\x34\x56\x78\x9a"
require 'cgi'
CGI.escape(str)
# => "%124Vx%9A%BC%DE%F1%23Eg%89%AB%CD%EF%124Vx%9A"

Taken from @J-Rou's comment

You can use Addressable::URI gem for that:

require 'addressable/uri'   
string = '\x12\x34\x56\x78\x9a\xbc\xde\xf1\x23\x45\x67\x89\xab\xcd\xef\x12\x34\x56\x78\x9a'
Addressable::URI.encode_component(string, Addressable::URI::CharacterClasses::QUERY)
# "%5Cx12%5Cx34%5Cx56%5Cx78%5Cx9a%5Cxbc%5Cxde%5Cxf1%5Cx23%5Cx45%5Cx67%5Cx89%5Cxab%5Cxcd%5Cxef%5Cx12%5Cx34%5Cx56%5Cx78%5Cx9a" 

It uses more modern format, than CGI.escape, for example, it properly encodes space as %20 and not as + sign, you can read more in "The application/x-www-form-urlencoded type" on Wikipedia.

2.1.2 :008 > CGI.escape('Hello, this is me')
 => "Hello%2C+this+is+me" 
2.1.2 :009 > Addressable::URI.encode_component('Hello, this is me', Addressable::URI::CharacterClasses::QUERY)
 => "Hello,%20this%20is%20me"