Class: ActiveHashcash::Stamp

Inherits:
ApplicationRecord show all
Defined in:
app/models/active_hashcash/stamp.rb

Overview

This is the model to store hashcash stamps. Unless you need something really specific, you should not need interact directly with that class.

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.filter_by(params) ⇒ Object 



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# File 'app/models/active_hashcash/stamp.rb', line 18

def self.filter_by(params)
  scope = all
  scope = scope.request_path_starts_with(params[:request_path_starts_with]) if params[:request_path_starts_with].present?
  scope = scope.ip_address_starts_with(params[:ip_address_starts_with]) if params[:ip_address_starts_with].present?
  scope = scope.created_from(params[:created_from]) if params[:created_from].present?
  scope = scope.created_to(params[:created_to]) if params[:created_to].present?
  scope = scope.bits_from(params[:bits_from]) if params[:bits_from].present?
  scope = scope.bits_to(params[:bits_to]) if params[:bits_to].present?
  scope
end

.mint(resource, attributes = {}) ⇒ Object 



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# File 'app/models/active_hashcash/stamp.rb', line 48

def self.mint(resource, attributes = {})
  new({
    version: 1,
    bits: ActiveHashcash.bits,
    date: Date.today.strftime(ActiveHashcash.date_format),
    resource: resource,
    ext: "sha256",
    rand: SecureRandom.alphanumeric(16),
    counter: 0,
  }.merge(attributes)).work
end

.parse(string) ⇒ Object

Parse and instantiate a stamp from a string which respects the hashcash format:

ver:bits:date:resource:[ext]:rand:counter


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# File 'app/models/active_hashcash/stamp.rb', line 42

def self.parse(string)
  args = string.to_s.split(":")
  return if args.size != 7
  new(version: args[0], bits: args[1], date: Date.strptime(args[2], ActiveHashcash.date_format), resource: args[3], ext: args[4], rand: args[5], counter: args[6])
end

.spend(string, resource, bits, date, options = {}) ⇒ Object

Verify and save the hashcash stamp. Saving in the database prevent from double spending the same stamp.



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# File 'app/models/active_hashcash/stamp.rb', line 31

def self.spend(string, resource, bits, date, options = {})
  return false unless stamp = parse(string)
  stamp.attributes = options
  stamp.verify(resource, bits, date) && stamp.save
rescue ActiveRecord::RecordNotUnique
  false
end

Instance Method Details

#authentic? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/models/active_hashcash/stamp.rb', line 65

def authentic?
  if ext == "sha256"
    Digest::SHA256.hexdigest(to_s).hex >> (256 - bits) == 0
  else
    Digest::SHA1.hexdigest(to_s).hex >> (160 - bits) == 0
  end
end

#to_s ⇒ Object 



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# File 'app/models/active_hashcash/stamp.rb', line 77

def to_s
  [version.to_i, bits, date.strftime("%y%m%d"), resource, ext, rand, counter].join(":")
end

#verify(resource, bits, date) ⇒ Object 



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# File 'app/models/active_hashcash/stamp.rb', line 73

def verify(resource, bits, date)
  self.resource == resource && self.bits >= bits && self.date >= date && !self.date.future? && authentic?
end

#work ⇒ Object 



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# File 'app/models/active_hashcash/stamp.rb', line 60

def work
  counter.next! until authentic?
  self
end