lib/dnspython/dns/rrset.py

   1 # Copyright (C) 2003-2007, 2009, 2010 Nominum, Inc.
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  14 # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15
  16 """DNS RRsets (an RRset is a named rdataset)"""
  17
  18 import dns.name
  19 import dns.rdataset
  20 import dns.rdataclass
  21 import dns.renderer
  22
  23 class RRset(dns.rdataset.Rdataset):
  24     """A DNS RRset (named rdataset).
  25
  26     RRset inherits from Rdataset, and RRsets can be treated as
  27     Rdatasets in most cases.  There are, however, a few notable
  28     exceptions.  RRsets have different to_wire() and to_text() method
  29     arguments, reflecting the fact that RRsets always have an owner
  30     name.
  31     """
  32
  33     __slots__ = ['name', 'deleting']
  34
  35     def __init__(self, name, rdclass, rdtype, covers=dns.rdatatype.NONE,
  36                  deleting=None):
  37         """Create a new RRset."""
  38
  39         super(RRset, self).__init__(rdclass, rdtype, covers)
  40         self.name = name
  41         self.deleting = deleting
  42
  43     def _clone(self):
  44         obj = super(RRset, self)._clone()
  45         obj.name = self.name
  46         obj.deleting = self.deleting
  47         return obj
  48
  49     def __repr__(self):
  50         if self.covers == 0:
  51             ctext = ''
  52         else:
  53             ctext = '(' + dns.rdatatype.to_text(self.covers) + ')'
  54         if not self.deleting is None:
  55             dtext = ' delete=' + dns.rdataclass.to_text(self.deleting)
  56         else:
  57             dtext = ''
  58         return '<DNS ' + str(self.name) + ' ' + \
  59                dns.rdataclass.to_text(self.rdclass) + ' ' + \
  60                dns.rdatatype.to_text(self.rdtype) + ctext + dtext + ' RRset>'
  61
  62     def __str__(self):
  63         return self.to_text()
  64
  65     def __eq__(self, other):
  66         """Two RRsets are equal if they have the same name and the same
  67         rdataset
  68
  69         @rtype: bool"""
  70         if not isinstance(other, RRset):
  71             return False
  72         if self.name != other.name:
  73             return False
  74         return super(RRset, self).__eq__(other)
  75
  76     def match(self, name, rdclass, rdtype, covers, deleting=None):
  77         """Returns True if this rrset matches the specified class, type,
  78         covers, and deletion state."""
  79
  80         if not super(RRset, self).match(rdclass, rdtype, covers):
  81             return False
  82         if self.name != name or self.deleting != deleting:
  83             return False
  84         return True
  85
  86     def to_text(self, origin=None, relativize=True, **kw):
  87         """Convert the RRset into DNS master file format.
  88
  89         @see: L{dns.name.Name.choose_relativity} for more information
  90         on how I{origin} and I{relativize} determine the way names
  91         are emitted.
  92
  93         Any additional keyword arguments are passed on to the rdata
  94         to_text() method.
  95
  96         @param origin: The origin for relative names, or None.
  97         @type origin: dns.name.Name object
  98         @param relativize: True if names should names be relativized
  99         @type relativize: bool"""
 100
 101         return super(RRset, self).to_text(self.name, origin, relativize,
 102                                           self.deleting, **kw)
 103
 104     def to_wire(self, file, compress=None, origin=None, **kw):
 105         """Convert the RRset to wire format."""
 106
 107         return super(RRset, self).to_wire(self.name, file, compress, origin,
 108                                           self.deleting, **kw)
 109
 110     def to_rdataset(self):
 111         """Convert an RRset into an Rdataset.
 112
 113         @rtype: dns.rdataset.Rdataset object
 114         """
 115         return dns.rdataset.from_rdata_list(self.ttl, list(self))
 116
 117
 118 def from_text_list(name, ttl, rdclass, rdtype, text_rdatas):
 119     """Create an RRset with the specified name, TTL, class, and type, and with
 120     the specified list of rdatas in text format.
 121
 122     @rtype: dns.rrset.RRset object
 123     """
 124
 125     if isinstance(name, (str, unicode)):
 126         name = dns.name.from_text(name, None)
 127     if isinstance(rdclass, (str, unicode)):
 128         rdclass = dns.rdataclass.from_text(rdclass)
 129     if isinstance(rdtype, (str, unicode)):
 130         rdtype = dns.rdatatype.from_text(rdtype)
 131     r = RRset(name, rdclass, rdtype)
 132     r.update_ttl(ttl)
 133     for t in text_rdatas:
 134         rd = dns.rdata.from_text(r.rdclass, r.rdtype, t)
 135         r.add(rd)
 136     return r
 137
 138 def from_text(name, ttl, rdclass, rdtype, *text_rdatas):
 139     """Create an RRset with the specified name, TTL, class, and type and with
 140     the specified rdatas in text format.
 141
 142     @rtype: dns.rrset.RRset object
 143     """
 144
 145     return from_text_list(name, ttl, rdclass, rdtype, text_rdatas)
 146
 147 def from_rdata_list(name, ttl, rdatas):
 148     """Create an RRset with the specified name and TTL, and with
 149     the specified list of rdata objects.
 150
 151     @rtype: dns.rrset.RRset object
 152     """
 153
 154     if isinstance(name, (str, unicode)):
 155         name = dns.name.from_text(name, None)
 156
 157     if len(rdatas) == 0:
 158         raise ValueError("rdata list must not be empty")
 159     r = None
 160     for rd in rdatas:
 161         if r is None:
 162             r = RRset(name, rd.rdclass, rd.rdtype)
 163             r.update_ttl(ttl)
 164             first_time = False
 165         r.add(rd)
 166     return r
 167
 168 def from_rdata(name, ttl, *rdatas):
 169     """Create an RRset with the specified name and TTL, and with
 170     the specified rdata objects.
 171
 172     @rtype: dns.rrset.RRset object
 173     """
 174
 175     return from_rdata_list(name, ttl, rdatas)