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from redis import Redis, ConnectionPool
from six.moves import xrange
from ._util import to_string
class Suggestion(object):
"""
Represents a single suggestion being sent or returned from the auto complete server
"""
def __init__(self, string, score=1.0, payload=None):
self.string = to_string(string)
self.payload = to_string(payload)
self.score = score
def __repr__(self):
return self.string
class SuggestionParser(object):
"""
Internal class used to parse results from the `SUGGET` command.
This needs to consume either 1, 2, or 3 values at a time from
the return value depending on what objects were requested
"""
def __init__(self, with_scores, with_payloads, ret):
self.with_scores = with_scores
self.with_payloads = with_payloads
if with_scores and with_payloads:
self.sugsize = 3
self._scoreidx = 1
self._payloadidx = 2
elif with_scores:
self.sugsize = 2
self._scoreidx = 1
elif with_payloads:
self.sugsize = 2
self._payloadidx = 1
else:
self.sugsize = 1
self._scoreidx = -1
self._sugs = ret
def __iter__(self):
for i in xrange(0, len(self._sugs), self.sugsize):
ss = self._sugs[i]
score = float(self._sugs[i + self._scoreidx]) if self.with_scores else 1.0
payload = self._sugs[i + self._payloadidx] if self.with_payloads else None
yield Suggestion(ss, score, payload)
class AutoCompleter(object):
"""
A client to RediSearch's AutoCompleter API
It provides prefix searches with optionally fuzzy matching of prefixes
"""
SUGADD_COMMAND = "FT.SUGADD"
SUGDEL_COMMAND = "FT.SUGDEL"
SUGLEN_COMMAND = "FT.SUGLEN"
SUGGET_COMMAND = "FT.SUGGET"
INCR = 'INCR'
WITHSCORES = 'WITHSCORES'
FUZZY = 'FUZZY'
WITHPAYLOADS = 'WITHPAYLOADS'
def __init__(self, key, host='localhost', port=6379, conn = None):
"""
Create a new AutoCompleter client for the given key, and optional host and port
If conn is not None, we employ an already existing redis connection
"""
self.key = key
self.redis = conn if conn is not None else Redis(
connection_pool = ConnectionPool(host=host, port=port))
def add_suggestions(self, *suggestions, **kwargs):
"""
Add suggestion terms to the AutoCompleter engine. Each suggestion has a score and string.
If kwargs['increment'] is true and the terms are already in the server's dictionary, we increment their scores
"""
pipe = self.redis.pipeline()
for sug in suggestions:
args = [AutoCompleter.SUGADD_COMMAND, self.key, sug.string, sug.score]
if kwargs.get('increment'):
args.append(AutoCompleter.INCR)
if sug.payload:
args.append('PAYLOAD')
args.append(sug.payload)
pipe.execute_command(*args)
return pipe.execute()[-1]
def len(self):
"""
Return the number of entries in the AutoCompleter index
"""
return self.redis.execute_command(AutoCompleter.SUGLEN_COMMAND, self.key)
def delete(self, string):
"""
Delete a string from the AutoCompleter index.
Returns 1 if the string was found and deleted, 0 otherwise
"""
return self.redis.execute_command(AutoCompleter.SUGDEL_COMMAND, self.key, string)
def get_suggestions(self, prefix, fuzzy = False, num = 10, with_scores = False, with_payloads=False):
"""
Get a list of suggestions from the AutoCompleter, for a given prefix
### Parameters:
- **prefix**: the prefix we are searching. **Must be valid ascii or utf-8**
- **fuzzy**: If set to true, the prefix search is done in fuzzy mode.
**NOTE**: Running fuzzy searches on short (<3 letters) prefixes can be very slow, and even scan the entire index.
- **with_scores**: if set to true, we also return the (refactored) score of each suggestion.
This is normally not needed, and is NOT the original score inserted into the index
- **with_payloads**: Return suggestion payloads
- **num**: The maximum number of results we return. Note that we might return less. The algorithm trims irrelevant suggestions.
Returns a list of Suggestion objects. If with_scores was False, the score of all suggestions is 1.
"""
args = [AutoCompleter.SUGGET_COMMAND, self.key, prefix, 'MAX', num]
if fuzzy:
args.append(AutoCompleter.FUZZY)
if with_scores:
args.append(AutoCompleter.WITHSCORES)
if with_payloads:
args.append(AutoCompleter.WITHPAYLOADS)
ret = self.redis.execute_command(*args)
results = []
if not ret:
return results
parser = SuggestionParser(with_scores, with_payloads, ret)
return [s for s in parser]
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