don't load sklearn libraries unless needed

src/documents/classifier.py

@@ -5,10 +5,6 @@ import pickle
 import re
 
 from django.conf import settings
-from sklearn.feature_extraction.text import CountVectorizer
-from sklearn.neural_network import MLPClassifier
-from sklearn.preprocessing import MultiLabelBinarizer, LabelBinarizer
-from sklearn.utils.multiclass import type_of_target
 
 from documents.models import Document, MatchingModel
 
@@ -109,6 +105,10 @@ class DocumentClassifier(object):
             pickle.dump(self.document_type_classifier, f)
 
     def train(self):
+        from sklearn.feature_extraction.text import CountVectorizer
+        from sklearn.neural_network import MLPClassifier
+        from sklearn.preprocessing import MultiLabelBinarizer, LabelBinarizer
+
         data = list()
         labels_tags = list()
         labels_correspondent = list()
@@ -265,6 +265,8 @@ class DocumentClassifier(object):
             return None
 
     def predict_tags(self, content):
+        from sklearn.utils.multiclass import type_of_target
+
         if self.tags_classifier:
             X = self.data_vectorizer.transform([preprocess_content(content)])
             y = self.tags_classifier.predict(X)

src/documents/tests/test_classifier.py

@@ -130,6 +130,15 @@ class TestClassifier(DirectoriesMixin, TestCase):
         new_classifier.reload()
         self.assertFalse(new_classifier.train())
 
+    @override_settings(MODEL_FILE=os.path.join(os.path.dirname(__file__), "data", "model.pickle"))
+    def test_load_and_classify(self):
+        self.generate_test_data()
+
+        new_classifier = DocumentClassifier()
+        new_classifier.reload()
+
+        self.assertCountEqual(new_classifier.predict_tags(self.doc2.content), [45, 12])
+
     def test_one_correspondent_predict(self):
         c1 = Correspondent.objects.create(name="c1", matching_algorithm=Correspondent.MATCH_AUTO)
         doc1 = Document.objects.create(title="doc1", content="this is a document from c1", correspondent=c1, checksum="A")

src/paperless/settings.py

@@ -4,7 +4,6 @@ import multiprocessing
 import os
 import re
 
-import dateparser
 from dotenv import load_dotenv
 
 from django.utils.translation import gettext_lazy as _
@@ -491,6 +490,10 @@ if PAPERLESS_TIKA_ENABLED:
 
 # List dates that should be ignored when trying to parse date from document text
 IGNORE_DATES = set()
+
+if os.getenv("PAPERLESS_IGNORE_DATES", ""):
+    import dateparser
+
     for s in os.getenv("PAPERLESS_IGNORE_DATES", "").split(","):
         d = dateparser.parse(s)
         if d: