dns.renderer.Renderer

Package dns :: Module renderer :: Class Renderer

[show private | hide private]

Type Renderer

object --+
         |
        Renderer

Helper class for building DNS wire-format messages.

Most applications can use the higher-level dns.message.Message class and its to_wire() method to generate wire-format messages. This class is for those applications which need finer control over the generation of messages.

Typical use:

   r = dns.renderer.Renderer(id=1, flags=0x80, max_size=512)
   r.add_question(qname, qtype, qclass)
   r.add_rrset(dns.renderer.ANSWER, rrset_1)
   r.add_rrset(dns.renderer.ANSWER, rrset_2)
   r.add_rrset(dns.renderer.AUTHORITY, ns_rrset)
   r.add_edns(0, 0, 4096)
   r.add_rrset(dns.renderer.ADDTIONAL, ad_rrset_1)
   r.add_rrset(dns.renderer.ADDTIONAL, ad_rrset_2)
   r.write_header()
   r.add_tsig(keyname, secret, 300, 1, 0, '', request_mac)
   wire = r.get_wire()

Method Summary
	`__init__(self, id, flags, max_size, origin)` Initialize a new renderer.
	`add_edns(self, edns, ednsflags, payload)` Add an EDNS OPT record to the message.
	`add_question(self, qname, rdtype, rdclass)` Add a question to the message.
	`add_rdataset(self, section, name, rdataset, **kw)` Add the rdataset to the specified section, using the specified name as the owner name.
	`add_rrset(self, section, rrset, **kw)` Add the rrset to the specified section.
	`add_tsig(self, keyname, secret, fudge, id, tsig_error, other_data, request_mac)` Add a TSIG signature to the message.
string	`get_wire(self)` Return the wire format message.
	`write_header(self)` Write the DNS message header.
Inherited from object
	`__delattr__(...)` x.__delattr__('name') <==> del x.name
	`__getattribute__(...)` x.__getattribute__('name') <==> x.name
	`__hash__(x)` x.__hash__() <==> hash(x)
	`__new__(T, S, ...)` T.__new__(S, ...) -> a new object with type S, a subtype of T
	`__reduce__(...)` helper for pickle
	`__reduce_ex__(...)` helper for pickle
	`__repr__(x)` x.__repr__() <==> repr(x)
	`__setattr__(...)` x.__setattr__('name', value) <==> x.name = value
	`__str__(x)` x.__str__() <==> str(x)

Instance Variable Summary
dict	`compress`: the compression table
int list of length 4	`counts`: list of the number of RRs in each section
int	`flags`: the message flags
int	`id`: the message id
string	`mac`: the MAC of the rendered message (if TSIG was used)
int	`max_size`: the maximum size of the message
dns.name.Name object	`origin`: the origin to use when rendering relative names
cStringIO.StringIO object	`output`: where rendering is written
int (dns.renderer.QUESTION, dns.renderer.ANSWER, dns.renderer.AUTHORITY, or dns.renderer.ADDITIONAL)	`section`: the section currently being rendered

Method Details

init(self, id=None, flags=0, max_size=65535, origin=None)
(Constructor)

Initialize a new renderer.

Parameters:: id - the message id
(type=int); flags - the DNS message flags
(type=int); max_size - the maximum message size; the default is 65535. If rendering results in a message greater than max_size, then dns.exception.TooBig will be raised.
(type=int); origin - the origin to use when rendering relative names
(type=dns.name.Namem or None.)

Overrides:: __builtin__.object.__init__

add_edns(self, edns, ednsflags, payload)

Add an EDNS OPT record to the message.

Parameters:: edns - The EDNS level to use.
(type=int); ednsflags - EDNS flag values.
(type=int); payload - The EDNS sender's payload field, which is the maximum size of UDP datagram the sender can handle.
(type=int)

See Also: RFC 2671

add_question(self, qname, rdtype, rdclass=1)

Add a question to the message.

Parameters:: qname - the question name
(type=dns.name.Name); rdtype - the question rdata type
(type=int); rdclass - the question rdata class
(type=int)

add_rdataset(self, section, name, rdataset, **kw)

Add the rdataset to the specified section, using the specified name as the owner name.

Any keyword arguments are passed on to the rdataset's to_wire() routine.

Parameters:: section - the section
(type=int); name - the owner name
(type=dns.name.Name object); rdataset - the rdataset
(type=dns.rdataset.Rdataset object)

add_rrset(self, section, rrset, **kw)

Add the rrset to the specified section.

Any keyword arguments are passed on to the rdataset's to_wire() routine.

Parameters:: section - the section
(type=int); rrset - the rrset
(type=dns.rrset.RRset object)

add_tsig(self, keyname, secret, fudge, id, tsig_error, other_data, request_mac)

Add a TSIG signature to the message.

Parameters:: keyname - the TSIG key name
(type=dns.name.Name object); secret - the secret to use
(type=string); fudge - TSIG time fudge; default is 300 seconds.
(type=int); id - the message id to encode in the tsig signature
(type=int); tsig_error - TSIG error code; default is 0.
(type=int); other_data - TSIG other data.
(type=string); request_mac - This message is a response to the request which had the specified MAC.
(type=string)

get_wire(self)

Return the wire format message.

Returns:: string

write_header(self)

Write the DNS message header.

Writing the DNS message header is done asfter all sections have been rendered, but before the optional TSIG signature is added.

Instance Variable Details

compress

the compression table

Type:: dict

counts

list of the number of RRs in each section

Type:: int list of length 4

flags

the message flags

Type:: int

id

the message id

Type:: int

mac

the MAC of the rendered message (if TSIG was used)

Type:: string

max_size

the maximum size of the message

Type:: int

origin

the origin to use when rendering relative names

Type:: dns.name.Name object

output

where rendering is written

Type:: cStringIO.StringIO object

section

the section currently being rendered

Type:: int (dns.renderer.QUESTION, dns.renderer.ANSWER, dns.renderer.AUTHORITY, or dns.renderer.ADDITIONAL)

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