refactor Bexter to add class Method so external Labeler can decode.

src/keri/core/coring.py

@@ -2013,7 +2013,7 @@ class Tagger(Matter):
         composable (bool): True when .qb64b and .qb2 are 24 bit aligned and round trip
 
     Properties:
-        tag (str): B64 primitive without prepad (alias of .soft)
+        tag (str): B64 .soft portion of code but without prepad
 
 
     Inherited Hidden:  (See Matter)
@@ -2660,14 +2660,15 @@ def _rawify(self, bext):
         raw = decodeB64(base)[ls:]  # convert and remove leader
         return raw  # raw binary equivalent of text
 
-    @property
-    def bext(self):
-        """
-        Property bext: Base64 text value portion of qualified b64 str
-        Returns the value portion of .qb64 with text code and leader removed
+    @classmethod
+    def _decode(cls, raw, code):
+        """Returns decoded raw as B64 str aka bext value
+
+        Returns:
+           bext (str): decoded raw as B64 str aka bext value
         """
-        _, _, _, _, ls = self.Sizes[self.code]
-        bext = encodeB64(bytes([0] * ls) + self.raw)
+        _, _, _, _, ls = cls.Sizes[code]
+        bext = encodeB64(bytes([0] * ls) + raw)
         ws = 0
         if ls == 0 and bext:
             if bext[0] == ord(b'A'):  # strip leading 'A' zero pad
@@ -2677,6 +2678,24 @@ def bext(self):
         return bext.decode('utf-8')[ws:]
 
 
+    @property
+    def bext(self):
+        """
+        Property bext: Base64 text value portion of qualified b64 str
+        Returns the value portion of .qb64 with text code and leader removed
+        """
+        return self._decode(raw=self.raw, code=self.code)
+        #_, _, _, _, ls = self.Sizes[self.code]
+        #bext = encodeB64(bytes([0] * ls) + self.raw)
+        #ws = 0
+        #if ls == 0 and bext:
+            #if bext[0] == ord(b'A'):  # strip leading 'A' zero pad
+                #ws = 1
+        #else:
+            #ws = (ls + 1) % 4
+        #return bext.decode('utf-8')[ws:]
+
+
 class Pather(Bexter):
     """
     Pather is a subclass of Bexter that provides SAD Path language specific functionality
@@ -2909,6 +2928,72 @@ def _resolve(self, val, ptr):
         return self._resolve(cur, ptr)
 
 
+class Labeler(Matter):
+    """
+    Labeler is subclass of Matter for CESR native field map labels and/or generic
+    textual field values. Labeler auto sizes the instance code to minimize
+    the total encoded size of associated field label or textual field value.
+
+
+
+    Attributes:
+
+    Inherited Properties:
+        (See Matter)
+
+
+    Properties:
+        label (str):  base value without encoding
+
+    Inherited Hidden:
+        (See Matter)
+
+    Hidden:
+        _label (str): base value without encoding
+
+    Methods:
+
+    """
+
+
+    def __init__(self, label='', code=None, **kwa):
+        """
+        Inherited Parameters:
+            (see Matter)
+
+        Parameters:
+            label (str | bytes):  base value before encoding
+
+        """
+        self._label = None
+        if label:
+            if hasattr(label, "decode"):  # make label a str
+                label = label.decode("utf-8")
+
+            if not Reb64.match(label.encode("utf-8")):
+                raise InvalidSoftError(f"Non Base64 chars in {tag=}.")
+
+            self._label = label
+
+
+        super(Labeler, self).__init__(code=code, **kwa)
+
+
+
+        if self.code not in LabelDex:
+            raise InvalidCodeError(f"Invalid code={self.code} for Labeler.")
+
+    @property
+    def label(self):
+        """Returns:
+            label (str): base value without encoding
+
+        getter for ._label. Makes ._label read only
+
+        """
+        return self._label
+
+
 
 class Verfer(Matter):
     """

tests/core/test_coring.py

@@ -40,7 +40,7 @@
 from keri.core import coring
 from keri.core.coring import (Saids, Sadder, Tholder, Seqner, NumDex, Number,
                               Dater, Bexter, Texter,
-                              TagDex, Tagger, Ilker, Traitor,
+                              TagDex, Tagger, Ilker, Traitor, Labeler,
                               Verser, Versage, )
 from keri.core.coring import Kindage, Kinds
 from keri.core.coring import (Sizage, MtrDex, Matter)
@@ -4270,6 +4270,19 @@ def test_pather():
     """ Done Test """
 
 
+def test_labeler():
+    """
+    Test Labeler subclass of Matter
+    """
+
+
+    with pytest.raises(EmptyMaterialError):
+        labeler = Labeler()  # defaults
+
+
+    """ Done Test """
+
+
 def test_verfer():
     """
     Test the support functionality for verifier subclass of crymat
@@ -5390,14 +5403,14 @@ def test_tholder():
     test_traitor()
     test_verser()
     test_diger()
-    #test_texter()
+    test_texter()
+    test_bexter()
+    test_labeler()
     #test_prodex()
-    #test_indexer()
     test_number()
     #test_seqner()
     #test_siger()
     #test_nexter()
     #test_tholder()
-    #test_labels()
-    #test_prefixer()
+    test_prefixer()