Parsing string to add to URL-encoded URL

Given the string:

"Hello there world"

how can I create a URL-encoded string like this:

"Hello%20there%20world"

I would also like to know what to do if the string has other symbols too, like:

"hello there: world, how are you"

What would is the easiest way to do so? I was going to parse and then build some code for that.

In 2019, URI.encode is obsolete and should not be used.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

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.

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:

• https://stackoverflow.com/questions/2678551/when-to-encode-space-to-plus-and-when-to-20
• https://stackoverflow.com/questions/1634271/url-encoding-the-space-character-or-20?rq=1
• 17.13.4 Form content types from the W3's "Forms in HTML documents" recommendations.

If anyone is interested, the newest way to do this is doing in ERB:

    <%= u "Hello World !" %>

This will render:

> Hello%20World%20%21

u is short for url_encode

You can find the docs here