Implement "chunked" TXT/SPF value support for long values

This implements it transparently at Record level. Providers that need things to
be chunked (seems to just be Route53 an Dyn) switch to use `chunked_values`, but
everything else can stick with `values`. I've run through each provider I have
access to verifying that things operate as expected/required. OVH and Azure are
untested.

octodns/provider/dyn.py

@@ -455,7 +455,7 @@ class DynProvider(BaseProvider):
         return [{
             'txtdata': v,
             'ttl': record.ttl,
-        } for v in record.values]
+        } for v in record.chunked_values]
 
     def _kwargs_for_SRV(self, record):
         return [{

octodns/provider/route53.py

@@ -114,8 +114,7 @@ class _Route53Record(object):
                 for v in record.values]
 
     def _values_for_quoted(self, record):
-        return ['"{}"'.format(v.replace('"', '\\"'))
-                for v in record.values]
+        return record.chunked_values
 
     _values_for_SPF = _values_for_quoted
     _values_for_TXT = _values_for_quoted

octodns/record.py

@@ -704,8 +704,8 @@ class SshfpRecord(_ValuesMixin, Record):
 _unescaped_semicolon_re = re.compile(r'\w;')
 
 
-class SpfRecord(_ValuesMixin, Record):
-    _type = 'SPF'
+class _ChunkedValuesMixin(_ValuesMixin):
+    CHUNK_SIZE = 255
 
     @classmethod
     def _validate_value(cls, value):
@@ -714,9 +714,29 @@ class SpfRecord(_ValuesMixin, Record):
         return []
 
     def _process_values(self, values):
+        ret = []
+        for v in values:
+            if v and v[0] == '"':
+                v = v[1:-1]
+            ret.append(v.replace('" "', ''))
+        return ret
+
+    @property
+    def chunked_values(self):
+        values = []
+        for v in self.values:
+            v = v.replace('"', '\\"')
+            vs = [v[i:i + self.CHUNK_SIZE]
+                  for i in range(0, len(v), self.CHUNK_SIZE)]
+            vs = '" "'.join(vs)
+            values.append('"{}"'.format(vs))
         return values
 
 
+class SpfRecord(_ChunkedValuesMixin, Record):
+    _type = 'SPF'
+
+
 class SrvValue(object):
 
     @classmethod
@@ -797,14 +817,5 @@ class SrvRecord(_ValuesMixin, Record):
         return [SrvValue(v) for v in values]
 
 
-class TxtRecord(_ValuesMixin, Record):
+class TxtRecord(_ChunkedValuesMixin, Record):
     _type = 'TXT'
-
-    @classmethod
-    def _validate_value(cls, value):
-        if _unescaped_semicolon_re.search(value):
-            return ['unescaped ;']
-        return []
-
-    def _process_values(self, values):
-        return values

tests/test_octodns_record.py

@@ -1490,3 +1490,59 @@ class TestRecordValidation(TestCase):
                 'value': 'this has some; semi-colons\; in it',
             })
         self.assertEquals(['unescaped ;'], ctx.exception.reasons)
+
+    def test_TXT_long_value_chunking(self):
+        expected = '"Lorem ipsum dolor sit amet, consectetur adipiscing ' \
+            'elit, seddo eiusmod tempor incididunt ut labore et dolore ' \
+            'magna aliqua. Ut enim ad minim veniam, quis nostrud ' \
+            'exercitation ullamco laboris nisi ut aliquip ex ea commodo ' \
+            'consequat. Duis aute irure dolor in" " reprehenderit in ' \
+            'voluptate velit esse cillum dolore eu fugiat nulla pariatur. ' \
+            'Excepteur sint occaecat cupidatat non proident, sunt in culpa ' \
+            'qui officia deserunt mollit anim id est laborum."'
+
+        # Single string
+        single = Record.new(self.zone, '', {
+            'type': 'TXT',
+            'ttl': 600,
+            'values': [
+                'hello world',
+                'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed'
+                'do eiusmod tempor incididunt ut labore et dolore magna '
+                'aliqua. Ut enim ad minim veniam, quis nostrud exercitation '
+                'ullamco laboris nisi ut aliquip ex ea commodo consequat. '
+                'Duis aute irure dolor in reprehenderit in voluptate velit '
+                'esse cillum dolore eu fugiat nulla pariatur. Excepteur sint '
+                'occaecat cupidatat non proident, sunt in culpa qui officia '
+                'deserunt mollit anim id est laborum.',
+                'this has some\; semi-colons\; in it',
+            ]
+        })
+        self.assertEquals(3, len(single.values))
+        self.assertEquals(3, len(single.chunked_values))
+        # Note we are checking that this normalizes the chunking, not that we
+        # get out what we put in.
+        self.assertEquals(expected, single.chunked_values[0])
+
+        # Chunked
+        chunked = Record.new(self.zone, '', {
+            'type': 'TXT',
+            'ttl': 600,
+            'values': [
+                '"hello world"',
+                '"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed'
+                'do eiusmod tempor incididunt ut labore et dolore magna '
+                'aliqua. Ut enim ad minim veniam, quis nostrud exercitation '
+                'ullamco laboris nisi ut aliquip ex" " ea commodo consequat. '
+                'Duis aute irure dolor in reprehenderit in voluptate velit '
+                'esse cillum dolore eu fugiat nulla pariatur. Excepteur sint '
+                'occaecat cupidatat non proident, sunt in culpa qui officia '
+                'deserunt mollit anim id est laborum."',
+                '"this has some\; semi-colons\; in it"',
+            ]
+        })
+        self.assertEquals(expected, chunked.chunked_values[0])
+        # should be single values, no quoting
+        self.assertEquals(single.values, chunked.values)
+        # should be chunked values, with quoting
+        self.assertEquals(single.chunked_values, chunked.chunked_values)