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https://github.com/PiBrewing/craftbeerpi4.git
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79 lines
2.7 KiB
Python
79 lines
2.7 KiB
Python
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class MQTTMatcher(object):
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"""Intended to manage topic filters including wildcards.
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Internally, MQTTMatcher use a prefix tree (trie) to store
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values associated with filters, and has an iter_match()
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method to iterate efficiently over all filters that match
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some topic name."""
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class Node(object):
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__slots__ = '_children', '_content'
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def __init__(self):
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self._children = {}
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self._content = None
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def __init__(self):
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self._root = self.Node()
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def __setitem__(self, key, value):
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"""Add a topic filter :key to the prefix tree
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and associate it to :value"""
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node = self._root
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for sym in key.split('/'):
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node = node._children.setdefault(sym, self.Node())
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node._content = value
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def __getitem__(self, key):
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"""Retrieve the value associated with some topic filter :key"""
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try:
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node = self._root
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for sym in key.split('/'):
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node = node._children[sym]
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if node._content is None:
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raise KeyError(key)
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return node._content
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except KeyError:
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raise KeyError(key)
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def __delitem__(self, key):
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"""Delete the value associated with some topic filter :key"""
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lst = []
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try:
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parent, node = None, self._root
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for k in key.split('/'):
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parent, node = node, node._children[k]
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lst.append((parent, k, node))
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# TODO
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node._content = None
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except KeyError:
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raise KeyError(key)
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else: # cleanup
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for parent, k, node in reversed(lst):
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if node._children or node._content is not None:
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break
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del parent._children[k]
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def iter_match(self, topic):
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"""Return an iterator on all values associated with filters
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that match the :topic"""
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lst = topic.split('/')
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normal = not topic.startswith('$')
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def rec(node, i=0):
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if i == len(lst):
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if node._content is not None:
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yield node._content
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else:
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part = lst[i]
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if part in node._children:
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for content in rec(node._children[part], i + 1):
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yield content
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if '+' in node._children and (normal or i > 0):
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for content in rec(node._children['+'], i + 1):
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yield content
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if '#' in node._children and (normal or i > 0):
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content = node._children['#']._content
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if content is not None:
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yield content
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return rec(self._root)
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