Parsing string to add to URL-encoded URL

While the current answer says to utilize URI.encode that has been deprecated and obsolete since Ruby 1.9.2. It is better to utilize CGI.escape or ERB::Util.url_encode.

In 2019, URI.encode is obsolete and should not be used.

---

require 'uri'

URI.encode("Hello there world")
#=> "Hello%20there%20world"
URI.encode("hello there: world, how are you")
#=> "hello%20there:%20world,%20how%20are%20you"

URI.decode("Hello%20there%20world")
#=> "Hello there world"

Ruby's URI is useful for this. You can build the entire URL programmatically and add the query parameters using that class, and it'll handle the encoding for you:

require 'uri'

uri = URI.parse('http://foo.com')
uri.query = URI.encode_www_form(
  's' => "Hello there world"
)
uri.to_s # => "http://foo.com?s=Hello+there+world"

The examples are useful:

URI.encode_www_form([["q", "ruby"], ["lang", "en"]])
#=> "q=ruby&lang=en"
URI.encode_www_form("q" => "ruby", "lang" => "en")
#=> "q=ruby&lang=en"
URI.encode_www_form("q" => ["ruby", "perl"], "lang" => "en")
#=> "q=ruby&q=perl&lang=en"
URI.encode_www_form([["q", "ruby"], ["q", "perl"], ["lang", "en"]])
#=> "q=ruby&q=perl&lang=en"

These links might also be useful:

• When to encode space to plus (+) or %20?
• URL encoding the space character: + or %20?
• 17.13.4 Form content types from the W3's "Forms in HTML documents" recommendations.