Class: Rdio::OM

Inherits:
Object show all
Defined in:
lib/rdio/simple_om.rb

Class Method Summary collapse

Class Method Details

.om(consumer, url, post_params, token = nil, method = 'POST', realm = nil) ⇒ Object 



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# File 'lib/rdio/simple_om.rb', line 51

def self.om(consumer, url, post_params, token=nil, method='POST', realm=nil)
  # A one-shot simple OAuth signature generator

  # the method must be upper-case
  method.upcase!

  # we want params as an Array of name / value pairs
  params = post_params.is_a?(Array) ? post_params : post_params.to_a

  # normalize the URL
  url = URI.parse(url)
  # scheme is lower-case
  url.scheme = url.scheme.downcase
  # remove username & password
  url.user = url.password = nil
  # host is lowercase
  url.host.downcase!

  # add URL params to the params
  if url.query
    CGI.parse(url.query).each { |k,vs| vs.each { |v| params.push([k,v]) } }
  end

  # remove the params and fragment
  url.query = nil
  url.fragment = nil

  # add OAuth params
  params = params + [
                     ['oauth_version', '1.0'],
                     ['oauth_timestamp', Time.now.to_i.to_s],
                     ['oauth_nonce', rand(1000000).to_s],
                     ['oauth_signature_method', 'HMAC-SHA1'],
                     ['oauth_consumer_key', consumer[0]],
                    ]

  # the consumer secret is the first half of the HMAC-SHA1 key
  hmac_key = consumer[1] + '&'

  if token != nil
    # include a token in params
    params.push ['oauth_token', token[0]]
    # and the token secret in the HMAC-SHA1 key
    hmac_key += token[1]
  end

  # Sort lexicographically, first after key, then after value.
  params.sort!
  # escape the key/value pairs and combine them into a string
  normalized_params = (params.collect {|p| percent_encode(p[0])+'='+percent_encode(p[1])}).join '&'

  # build the signature base string
  signature_base_string = (percent_encode(method) +
                           '&' + percent_encode(url.to_s) +
                           '&' + percent_encode(normalized_params))

  # HMAC-SHA1
  hmac = Digest::HMAC.new(hmac_key, Digest::SHA1)
  hmac.update(signature_base_string)

  # Calculate the digest base 64. Drop the trailing \n
  oauth_signature = [hmac.digest].pack('m0').strip

  # Build the Authorization header
  if realm
    authorization_params = [['realm', realm]]
  else
    authorization_params = []
  end
  authorization_params.push(['oauth_signature', oauth_signature])

  # we only want certain params in the auth header
  oauth_params = ['oauth_version', 'oauth_timestamp', 'oauth_nonce',
                  'oauth_signature_method', 'oauth_signature',
                  'oauth_consumer_key', 'oauth_token']
  authorization_params.concat(params.select { |param| nil != oauth_params.index(param[0]) })

  return 'OAuth ' + (authorization_params.collect {|param| '%s="%s"' % param}).join(', ')
end

.percent_encode(s) ⇒ Object 



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# File 'lib/rdio/simple_om.rb', line 131

def self.percent_encode(s)
  chars = s.chars.map do |c|
    if ((c >= '0' and c <= '9') or
        (c >= 'A' and c <= 'Z') or
        (c >= 'a' and c <= 'z') or
        c == '-' or c == '.' or c == '_' or c == '~')
      c
    else
      '%%%02X' % c.ord
    end
  end
  chars.join
end