Module: Jabber::Caps

Defined in:
lib/xmpp4r/caps/c.rb,
lib/xmpp4r/caps/helper/helper.rb,
lib/xmpp4r/caps/helper/generator.rb

Defined Under Namespace

Classes: C, Helper

Constant Summary collapse

NS_CAPS =
'http://jabber.org/protocol/caps'

Class Method Summary collapse

Class Method Details

.generate_ver(identities, features, forms = [], hash = 'sha-1') ⇒ Object

Implementation of the algorithm defined at: www.xmpp.org/extensions/xep-0115.html#ver-gen


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# File 'lib/xmpp4r/caps/helper/generator.rb', line 114

def self.generate_ver(identities, features, forms=[], hash='sha-1')
  s = generate_ver_str(identities, features, forms)

  # 9. Compute the verification string by hashing S using the
  # algorithm specified in the 'hash' attribute (e.g., SHA-1 as
  # defined in RFC 3174 [17]). The hashed data MUST be generated
  # with binary output and encoded using Base64 as specified in
  # Section 4 of RFC 4648 [18] (note: the Base64 output MUST NOT
  # include whitespace and MUST set padding bits to zero). [19]

  # See http://www.iana.org/assignments/hash-function-text-names
  hash_klass = case hash
                 when 'md2' then nil
                 when 'md5' then Digest::MD5
                 when 'sha-1' then Digest::SHA1
                 when 'sha-224' then nil
                 when 'sha-256' then Digest::SHA256
                 when 'sha-384' then Digest::SHA384
                 when 'sha-512' then Digest::SHA512
               end
  if hash_klass
    Base64::encode64(hash_klass::digest(s)).strip
  else
    nil
  end
end

.generate_ver_from_discoinfo(query, hash = 'sha-1') ⇒ Object

Generate a ver hash from a Jabber::Discovery::IqQueryDiscoInfo result

query
Jabber::Discovery::IqQueryDiscoInfo

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# File 'lib/xmpp4r/caps/helper/generator.rb', line 144

def self.generate_ver_from_discoinfo(query, hash='sha-1')
  identities = []
  features = []
  forms = []
  query.each_element do |element|
    if element.kind_of? Discovery::Identity
      identities << element
    elsif element.kind_of? Discovery::Feature
      features << element
    elsif element.kind_of? Dataforms::XData
      forms << element
    end
  end
  generate_ver(identities, features, forms, hash)
end

.generate_ver_str(identities, features, forms = []) ⇒ Object


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# File 'lib/xmpp4r/caps/helper/generator.rb', line 14

def self.generate_ver_str(identities, features, forms=[])
  # 1.  Initialize an empty string S.
  s = ''

  # 2. Sort the service discovery identities [14] by category and
  # then by type (if it exists) and then by xml:lang (if it
  # exists), formatted as CATEGORY '/' [TYPE] '/' [LANG] '/'
  # [NAME]. Note that each slash is included even if the TYPE,
  # LANG, or NAME is not included.
  identities.sort! do |identity1,identity2|
    cmp_result = nil
    [:category, :type, :xml_lang, :iname].each do |field|
      value1 = identity1.send(field)
      value2 = identity2.send(field)

      if value1 != value2
        cmp_result = value1 <=> value2
        break
      end
    end


    cmp_result
  end

  # 3. For each identity, append the 'category/type/lang/name' to
  # S, followed by the '<' character.
  s += identities.collect do |identity|
    [:category, :type, :xml_lang, :iname].collect do |field|
      identity.send(field).to_s
    end.join('/') + '<'
  end.join
  
  # 4. Sort the supported service discovery features. [15]
  features.sort! do |feature1,feature2|
    feature1.var <=> feature2.var
  end

  # 5. For each feature, append the feature to S, followed by the
  # '<' character.
  s += features.collect do |feature|
    feature.var.to_s + '<'
  end.join

  # 6. If the service discovery information response includes
  # XEP-0128 data forms, sort the forms by the FORM_TYPE (i.e., by
  # the XML character data of the <value/> element).
  forms.sort! do |form1,form2|
    fform_type1 = form1.field('FORM_TYPE')
    fform_type2 = form2.field('FORM_TYPE')
    form_type1 = fform_type1 ? fform_type1.values.to_s : nil
    form_type2 = fform_type2 ? fform_type2.values.to_s : nil
    form_type1 <=> form_type2
  end

  # 7. For each extended service discovery information form:
  forms.each do |form|
    # 7.1. Append the XML character data of the FORM_TYPE field's
    # <value/> element, followed by the '<' character.
    fform_type = form.field('FORM_TYPE')
    form_type = fform_type ? fform_type.first_element_text('value') : nil
    s += "#{form_type}<"

    # 7.2. Sort the fields by the value of the "var" attribute.
    fields = form.fields(false).sort do |field1,field2|
      field1.var <=> field2.var
    end

    # 7.3. For each field:

    fields.each do |field|
      # 7.3.1. Append the value of the "var" attribute, followed by
      # the '<' character.
      s += "#{field.var}<"

      # 7.3.2. Sort values by the XML character data of the <value/>
      # element.
      values = field.values.sort do |value1,value2|
        value1 <=> value2
      end

      # 7.3.3. For each <value/> element, append the XML character
      # data, followed by the '<' character.
      s += values.collect do |value|
        "#{value}<"
      end.join
    end
  end

  # 8. Ensure that S is encoded according to the UTF-8 encoding
  # (RFC 3269 [16]).

  # (given in XMPP4R)

  s
end