example.rb

require 'rubygems'
require 'net/http'
require 'webmock'

original_request_uri = nil
WebMock.after_request do |request, response|
  original_request_uri = request.uri
end

host = "encrypted.google.com"

http = Net::HTTP.new(host, 443)
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_NONE

url = "/search?abc=%2B"

WebMock.allow_net_connect!
http.request(Net::HTTP::Post.new(url))

WebMock.disable_net_connect!
WebMock.stub_request(:post, original_request_uri.to_s).to_return(:body => 'stubbed')

http.request(Net::HTTP::Post.new(url))

output.sh

✗ ruby example.rb
/Users/myron/.rvm/gems/ruby-1.8.7-p334/gems/webmock-1.7.0/lib/webmock/http_lib_adapters/net_http.rb:113:in `request': Real HTTP connections are disabled. Unregistered request: POST https://encrypted.google.com/search?abc=+ with headers {'Accept'=>'*/*'} (WebMock::NetConnectNotAllowedError)

You can stub this request with the following snippet:

stub_request(:post, "https://encrypted.google.com/search?abc=%20").
  with(:headers => {'Accept'=>'*/*'}).
  to_return(:status => 200, :body => "", :headers => {})

registered request stubs:

stub_request(:post, "https://encrypted.google.com/search?abc=%20")

============================================================
	from example.rb:24