kpsul/shared/views/autocomplete.py
2020-05-07 15:44:37 +02:00

184 lines
5.5 KiB
Python

from collections import namedtuple
from dal import autocomplete
from django.conf import settings
from django.db.models import Q
if getattr(settings, "LDAP_SERVER_URL", None):
from ldap3 import Connection
else:
# shared.tests.testcases.TestCaseMixin.mockLDAP needs
# Connection to be defined
Connection = None
class SearchUnit:
"""Base class for all the search utilities.
A search unit should implement a `search` method taking a list of keywords as
argument and returning an iterable of search results.
"""
def search(self, _keywords):
raise NotImplementedError(
"Class implementing the SeachUnit interface should implement the search "
"method"
)
# ---
# Model-based search
# ---
class ModelSearch(SearchUnit):
"""Basic search engine for models based on filtering.
The class should be configured through its `model` class attribute: the `search`
method will return a queryset of instances of this model. The `search_fields`
attributes indicates which fields to search in.
Example:
>>> from django.contrib.auth.models import User
>>>
>>> class UserSearch(ModelSearch):
... model = User
... search_fields = ["username", "first_name", "last_name"]
>>>
>>> user_search = UserSearch() # has type ModelSearch[User]
>>> user_search.search(["toto", "foo"]) # returns a queryset of Users
"""
model = None
search_fields = []
def get_queryset_filter(self, keywords):
filter_q = Q()
if not keywords:
return filter_q
for keyword in keywords:
kw_filter = Q()
for field in self.search_fields:
kw_filter |= Q(**{"{}__icontains".format(field): keyword})
filter_q &= kw_filter
return filter_q
def search(self, keywords):
"""Returns the queryset of model instances matching all the keywords.
The semantic of the search is the following: a model instance appears in the
search results iff all of the keywords given as arguments occur in at least one
of the search fields.
"""
return self.model.objects.filter(self.get_queryset_filter(keywords))
class Select2QuerySetView(ModelSearch, autocomplete.Select2QuerySetView):
"""Compatibility layer between ModelSearch and Select2QuerySetView."""
def get_queryset(self):
keywords = self.q.split()
return super().search(keywords)
# ---
# LDAP search
# ---
Clipper = namedtuple("Clipper", ["clipper", "fullname"])
class LDAPSearch(SearchUnit):
ldap_server_url = getattr(settings, "LDAP_SERVER_URL", None)
domain_component = "dc=spi,dc=ens,dc=fr"
search_fields = ["cn", "uid"]
def get_ldap_query(self, keywords):
"""Return a search query with the following semantics:
A Clipper appears in the search results iff all of the keywords given as
arguments occur in at least one of the search fields.
"""
# Dumb but safe
keywords = filter(str.isalnum, keywords)
ldap_filters = []
for keyword in keywords:
ldap_filter = "(|{})".format(
"".join(
"({}=*{}*)".format(field, keyword) for field in self.search_fields
)
)
ldap_filters.append(ldap_filter)
return "(&{})".format("".join(ldap_filters))
def search(self, keywords):
"""Return a list of Clipper objects matching all the keywords."""
query = self.get_ldap_query(keywords)
if Connection is None or query == "(&)":
return []
with Connection(self.ldap_server_url) as conn:
conn.search(self.domain_component, query, attributes=self.search_fields)
return [Clipper(entry.uid.value, entry.cn.value) for entry in conn.entries]
# ---
# Composition of autocomplete units
# ---
class Compose:
"""Search with several units and remove duplicate results.
The `search_units` class attribute should be a list of tuples of the form `(name,
uniq_key, search_unit)`.
The `search` method produces a dictionary whose keys are the `name`s given in
`search_units` and whose values are iterables produced by the different search
units.
The `uniq_key`s are used to remove duplicates: for instance, say that search unit
1 has `uniq_key = "username"` and search unit 2 has `uniq_key = "clipper"`, then
search results from unit 2 whose `.clipper` attribute is equal to the
`.username` attribute of some result from unit 1 are omitted.
Typical Example:
>>> from django.contrib.auth.models import User
>>>
>>> class UserSearch(ModelSearch):
... model = User
... search_fields = ["username", "first_name", "last_name"]
>>>
>>> class UserAndClipperSearch(Compose):
... search_units = [
... ("users", "username", UserSearch),
... ("clippers", "clipper", LDAPSearch),
... ]
In this example, clipper accounts that already have an associated user (i.e. with a
username equal to the clipper login), will not appear in the results.
"""
search_units = []
def search(self, keywords):
uniq_results = set()
results = {}
for name, uniq_key, search_unit in self.search_units:
res = search_unit().search(keywords)
res = [r for r in res if getattr(r, uniq_key) not in uniq_results]
uniq_results |= set((getattr(r, uniq_key) for r in res))
results[name] = res
return results