Class: RubyDNS::Transaction

Inherits:
Object
  • Object
show all
Defined in:
lib/rubydns/transaction.rb

Overview

This class provides all details of a single DNS question and answer. This is used by the DSL to provide DNS related functionality.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(server, query, question, resource_class, answer) ⇒ Transaction

Returns a new instance of Transaction.



41
42
43
44
45
46
47
48
49
 
# File 'lib/rubydns/transaction.rb', line 41

def initialize(server, query, question, resource_class, answer)
	@server = server
	@query = query
	@question = question
	@resource_class = resource_class
	@answer = answer
	
	@question_appended = false
end

Instance Attribute Details

#answer ⇒ Object (readonly)

The current full answer to the incoming query.



62
63
64
 
# File 'lib/rubydns/transaction.rb', line 62

def answer
  @answer
end

#query ⇒ Object (readonly)

The incoming query which is a set of questions.



56
57
58
 
# File 'lib/rubydns/transaction.rb', line 56

def query
  @query
end

#question ⇒ Object (readonly)

The question that this transaction represents.



59
60
61
 
# File 'lib/rubydns/transaction.rb', line 59

def question
  @question
end

#resource_class ⇒ Object (readonly)

The resource_class that was requested. This is typically used to generate a response.



53
54
55
 
# File 'lib/rubydns/transaction.rb', line 53

def resource_class
  @resource_class
end

Instance Method Details

#append!(*resources) ⇒ Object

Append a given set of resources to the answer. The last argument can optionally be a hash of options.

options[:ttl]

Specify the TTL for the resource

options[:name]

Override the name (question) of the response.

This function can be used to supply multiple responses to a given question. For example, each argument is expected to be an instantiated resource from Resolv::DNS::Resource module.



156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
 
# File 'lib/rubydns/transaction.rb', line 156

def append! (*resources)
	append_question!

	options = resources.last.kind_of?(Hash) ? resources.pop.dup : {}
	options[:ttl] ||= 16000
	options[:name] ||= @question.to_s + "."

	resources.each do |resource|
		@answer.add_answer(options[:name], options[:ttl], resource)
	end

	@answer.encode

	true
end

#append_query!(name, resource_type = nil) ⇒ Object

Run a new query through the rules with the given name and resource type. The results of this query are appended to the current transactions answer.



81
82
83
 
# File 'lib/rubydns/transaction.rb', line 81

def append_query!(name, resource_type = nil)
	Transaction.new(@server, @query, name, RubyDNS.lookup_resource_class(resource_type) || @resource_class, @answer).process
end

#failure!(rcode) ⇒ Object

This function indicates that there was a failure to resolve the given question. The single argument must be an integer error code, typically given by the constants in Resolv::DNS::RCode.

The easiest way to use this function it to simply supply a symbol. Here is a list of the most commonly used ones:

:NoError

No error occurred.

:FormErr:: The incoming data was not formatted correctly.

:ServFail

The operation caused a server failure (internal error, etc).

:NXDomain

Non-eXistant Domain (domain record does not exist).

:NotImp

The operation requested is not implemented.

:Refused

The operation was refused by the server.

:NotAuth

The server is not authoritive for the zone.

See www.rfc-editor.org/rfc/rfc2929.txt for more information about DNS error codes (specifically, page 3).



189
190
191
192
193
194
195
196
197
198
199
 
# File 'lib/rubydns/transaction.rb', line 189

def failure! (rcode)
	append_question!

	if rcode.kind_of? Symbol
		@answer.rcode = Resolv::DNS::RCode.const_get(rcode)
	else
		@answer.rcode = rcode.to_i
	end

	true
end

#name ⇒ Object

Return the name of the question, which is typically the requested hostname.



70
71
72
 
# File 'lib/rubydns/transaction.rb', line 70

def name
	@question.to_s
end

#passthrough!(resolver, &block) ⇒ Object

Use the given resolver to respond to the question. This will query the resolver and merge! the answer if one is received. If recursion is not requested, the result is failure!(:Refused). If the resolver does not respond, the result is failure!(:NXDomain)

If a block is supplied, this function yields with the reply and reply_name if successful. This could be used, for example, to update a cache.



96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
 
# File 'lib/rubydns/transaction.rb', line 96

def passthrough! (resolver, &block)
	# Were we asked to recursively find this name?
	if @query.rd
		reply, reply_name = resolver.query(name, resource_class)

		if reply
			if block_given?
				yield(reply, reply_name)
			end

			@answer.merge!(reply)
		else
			failure!(:NXDomain)
		end
	else
		failure!(:Refused)
	end

	true
end

#process ⇒ Object 



85
86
87
 
# File 'lib/rubydns/transaction.rb', line 85

def process
	@server.process(name, record_type, self)
end

#record_type ⇒ Object

Return the type of record (eg. A, MX) as a String.



65
66
67
 
# File 'lib/rubydns/transaction.rb', line 65

def record_type
	@resource_class.name.split("::").last
end

#respond!(*data) ⇒ Object

Respond to the given query with a resource record. The arguments to this function depend on the resource_class requested. The last argument can optionally be a hash of options.

options[:resource_class]

Override the default resource_class

options[:ttl]

Specify the TTL for the resource

options[:name]

Override the name (question) of the response.

for A records

respond!("1.2.3.4")

for MX records

respond!("mail.blah.com", 10)

This function instantiates the resource class with the supplied arguments, and then passes it to append!.

See Resolv::DNS::Resource for more information about the various resource_classs available. www.ruby-doc.org/stdlib/libdoc/resolv/rdoc/index.html



134
135
136
137
138
139
140
141
142
143
144
145
 
# File 'lib/rubydns/transaction.rb', line 134

def respond! (*data)
	options = data.last.kind_of?(Hash) ? data.pop : {}
	
	case options[:resource_class]
	when nil
		append!(@resource_class.new(*data), options)
	when Class
		append!(options[:resource_class].new(*data), options)
	else
		raise ArgumentError, "Could not instantiate resource!"
	end
end

#to_s ⇒ Object

Suitable for debugging purposes



75
76
77
 
# File 'lib/rubydns/transaction.rb', line 75

def to_s
	"#{name} #{record_type}"
end