This Ruby code uses a unified XML format to create a password record on a web server. It's intended to be run as a batch file which gets called from another Ruby application called maintain_projectx which gets called from a cronjob.

In this example the password is stored on the server not for authentication but simply to provide a reminder service in the event the user forgets it.

require 'net/http'
require 'rexml/document'
include REXML

class ProjectXClient
  attr :doc
  def initialize(raw_url)
    url = URI.escape(raw_url)
    xml_data = Net::HTTP.get_response(URI.parse(url)).body
    @doc = Document.new(xml_data)
  end
  
end

if __FILE__ == $0

  xml_project = <<PROJECT
  <project name='password'>
    <method name='create'>
      <params>
        <param var='password' val='p6789c'/>
        <param var='title' val='hotmail'/>
      </params>
    </method>
  </project>
PROJECT
  
  pxc = ProjectXClient.new("http://yourdomain.com/p/projectx.cgi?xml_project=" + xml_project)
  doc = pxc.doc
  puts doc
    
end

output -what's returned from the server is an XML response containing a result. The result echos the method executed and the output from that method, which in this instance is the xml record node 'entry'.

<result method='rtn_create'>
  <append id='19367'>
    <entry id='19367'>
      <password>p6789c</password>
      <title>hotmail</title>
      <description/>
    </entry>
  </append>
</result>

No regexes, allows URLs with ports or IPs. Inspiration from here

  validates_each :href, :on => :create do |record, attr, value|
    begin
      uri = URI.parse(value)
      if uri.class != URI::HTTP
        record.errors.add(attr, 'Only HTTP protocol addresses can be used')
      end
    rescue URI::InvalidURIError
      record.errors.add(attr, 'The format of the url is not valid.')
    end
  end

// find out the current url / uri in *.rhtml file
// is quite simple with the request object

<% page = request.request_uri %>
page: <%= page %>

// but then different urls mean the same page
// (../admin = ../admin/ = ../admin/index = ..admin/index/)
// and maybe the id is unwanted too (../admin/show/8)
// so below is an alternative with control on which parameter is used

<% page = "/" + request.path_parameters['controller'] + "/" + request.path_parameters['action'] %>
page: <%= page %>

Here is a quick/basic URI validation library for your Rails app:

require 'net/http'

# Original credits: http://blog.inquirylabs.com/2006/04/13/simple-uri-validation/
# HTTP Codes: http://www.ruby-doc.org/stdlib/libdoc/net/http/rdoc/classes/Net/HTTPResponse.html

class ActiveRecord::Base
  def self.validates_uri_existence_of(*attr_names)
    configuration = { :message => "is not valid or not responding", :on => :save, :with => nil }
    configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
    
    raise(ArgumentError, "A regular expression must be supplied as the :with option of the configuration hash") unless configuration[:with].is_a?(Regexp)
    
    validates_each(attr_names, configuration) do |r, a, v|
        if v.to_s =~ configuration[:with] # check RegExp
              begin # check header response
                  case Net::HTTP.get_response(URI.parse(v))
                    when Net::HTTPSuccess then true
                    else r.errors.add(a, configuration[:message]) and false
                  end 
              rescue # Recover on DNS failures.. 
                  r.errors.add(a, configuration[:message]) and false
              end
        else
          r.errors.add(a, configuration[:message]) and false
        end 
    end
  end
end

Save the code above into a file in your 'lib' directory. ex: validates_uri_existence_of.rb. Include the file in your environment.rb (ex: require 'validates_uri_existence_of').

And now you can use the validator in any model by calling:

validates_uri_existence_of :url, :with =>
        /(^$)|(^(http|https)://[a-z0-9] ([-.]{1}[a-z0-9] )*.[a-z]{2,5}(([0-9]{1,5})?/.*)?$)/ix

Above code validates the URI/URL against a regular expression first, and then does a HEAD query to confirm that the page is alive (HTTPSuccess code is returned). You could easily modify the code to extend the functionality as you wish.

More info in this post.

// reads and extracts regexp using open-uri

require "open-uri"; include OpenURI
alpha=('a'..'z').to_a

snames=File.new('stations.txt','w')
alpha.each {|a|
open("http://www.irishrail.ie/your_journey/stationpicker.asp?id=#{a}&box=From") {|f|
    f.each_line {|line| snames.puts line}
}}

snames=File.new('stations.txt','r')
data=snames.read
rx1=/sendValue\('([a-zA-Z]+)/
sarr=data.scan(rx1)
stations=sarr.collect{|s| s[0]}
stations.uniq!
puts stations

Found at http://www.juretta.com/log/2006/08/13/ruby_net_http_and_open-uri/

# (sudo) gem install rio
require 'rubygems'
require 'rio'
# open an URI an copy the content into a file
rio('http://www.juretta.com/') > rio('juretta_index.html')

Cool syntax!

require 'open-uri'

class ActiveRecord::Base
  def self.validates_uri_existence_of(*attr_names)
    configuration = { :message => "is not a valid web address" }
    configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
    validates_each attr_names do |m, a, v|
      begin
        # Try to open the URI
        open v
      rescue
        # Report the error if it throws an exception
        m.errors.add(a, configuration[:message])
      end
    end
  end
end

Details on my blog.

To encode the web parameters for a URL query string.

require 'uri'
val = URI.escape("my parameter value")

This function will turn any string into a safe string usable in a URI.

function dirify($s) {
     $s = convert_high_ascii($s);  ## convert high-ASCII chars to 7bit.
     $s = strtolower($s);           ## lower-case.
     $s = strip_tags($s);       ## remove HTML tags.
     $s = preg_replace('!&[^;\s]+;!','',$s);         ## remove HTML entities.
     $s = preg_replace('![^\w\s.]!','',$s);           ## remove non-word/space/period chars.
     $s = preg_replace('!\s+!','-',$s);               ## change space chars to dashes.
     return $s;    
}

function convert_high_ascii($s) {
 	$HighASCII = array(
 		"!\xc0!" => 'A',    # A`
 		"!\xe0!" => 'a',    # a`
 		"!\xc1!" => 'A',    # A'
 		"!\xe1!" => 'a',    # a'
 		"!\xc2!" => 'A',    # A^
 		"!\xe2!" => 'a',    # a^
 		"!\xc4!" => 'Ae',   # A:
 		"!\xe4!" => 'ae',   # a:
 		"!\xc3!" => 'A',    # A~
 		"!\xe3!" => 'a',    # a~
 		"!\xc8!" => 'E',    # E`
 		"!\xe8!" => 'e',    # e`
 		"!\xc9!" => 'E',    # E'
 		"!\xe9!" => 'e',    # e'
 		"!\xca!" => 'E',    # E^
 		"!\xea!" => 'e',    # e^
 		"!\xcb!" => 'Ee',   # E:
 		"!\xeb!" => 'ee',   # e:
 		"!\xcc!" => 'I',    # I`
 		"!\xec!" => 'i',    # i`
 		"!\xcd!" => 'I',    # I'
 		"!\xed!" => 'i',    # i'
 		"!\xce!" => 'I',    # I^
 		"!\xee!" => 'i',    # i^
 		"!\xcf!" => 'Ie',   # I:
 		"!\xef!" => 'ie',   # i:
 		"!\xd2!" => 'O',    # O`
 		"!\xf2!" => 'o',    # o`
 		"!\xd3!" => 'O',    # O'
 		"!\xf3!" => 'o',    # o'
 		"!\xd4!" => 'O',    # O^
 		"!\xf4!" => 'o',    # o^
 		"!\xd6!" => 'Oe',   # O:
 		"!\xf6!" => 'oe',   # o:
 		"!\xd5!" => 'O',    # O~
 		"!\xf5!" => 'o',    # o~
 		"!\xd8!" => 'Oe',   # O/
 		"!\xf8!" => 'oe',   # o/
 		"!\xd9!" => 'U',    # U`
 		"!\xf9!" => 'u',    # u`
 		"!\xda!" => 'U',    # U'
 		"!\xfa!" => 'u',    # u'
 		"!\xdb!" => 'U',    # U^
 		"!\xfb!" => 'u',    # u^
 		"!\xdc!" => 'Ue',   # U:
 		"!\xfc!" => 'ue',   # u:
 		"!\xc7!" => 'C',    # ,C
 		"!\xe7!" => 'c',    # ,c
 		"!\xd1!" => 'N',    # N~
 		"!\xf1!" => 'n',    # n~
 		"!\xdf!" => 'ss'
 	);
 	$find = array_keys($HighASCII);
 	$replace = array_values($HighASCII);
 	$s = preg_replace($find,$replace,$s);
     return $s;
}

This function transforms an HTTP request path (ie, $_SERVER['PATH_INFO']) into its canonical form, removing empty path elements and relative path elements (//, /./, /../). It assumes that there is a trailing slash on the path if it's a directory.

function canonical_path($path) {
    $canonical = preg_replace('|/\.?(?=/)|','',$path);
    while (($collapsed = preg_replace('|/[^/]+/\.\./|','/',$canonical,1)) !== $canonical) {
        $canonical = $collapsed;
    }
    $canonical = preg_replace('|^/\.\./|','/',$canonical);
    return $canonical;
}