From b8b9244fc84ff2db339f3edde9160f5353653498 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20P=C3=A9ters?= <fpeters@entrouvert.com>
Date: Tue, 26 May 2020 15:21:31 +0200
Subject: [PATCH] misc: add filter to detect language (#43335)

---
 debian/control                    |  1 +
 tests/test_templates.py           | 13 +++++++++++++
 tox.ini                           |  1 +
 wcs/qommon/templatetags/qommon.py | 16 ++++++++++++++++
 4 files changed, 31 insertions(+)

diff --git a/debian/control b/debian/control
index 4fde2df15..82acea38e 100644
--- a/debian/control
+++ b/debian/control
@@ -30,6 +30,7 @@ Recommends: libreoffice-writer-nogui | libreoffice-writer,
     poppler-utils,
     python3-dns,
     python3-docutils,
+    python3-langdetect,
     python3-magic,
     python3-qrcode,
     python3-xlwt
diff --git a/tests/test_templates.py b/tests/test_templates.py
index baf8dc7ba..7a298a233 100644
--- a/tests/test_templates.py
+++ b/tests/test_templates.py
@@ -4,6 +4,11 @@ import datetime
 import pytest
 import string
 
+try:
+    import langdetect
+except ImportError:
+    langdetect = None
+
 from django.test import override_settings
 from quixote import cleanup
 from wcs.qommon.substitution import CompatibilityNamesDict
@@ -604,3 +609,11 @@ def test_phonenumber_fr():
     assert t.render({'number': None}) == 'None'
     t = Template('{{ number|decimal|phonenumber_fr }}')
     assert t.render({'number': '1,33'}) == '1.33'
+
+
+@pytest.mark.skipif('langdetect is None')
+def test_language_detect():
+    t = Template('{{ plop|language_detect }}')
+    assert t.render({'plop': 'Good morning world'}) == 'en'
+    assert t.render({'plop': 'Bonjour tout le monde'}) == 'fr'
+    assert t.render({'plop': '2132133'}) == ''
diff --git a/tox.ini b/tox.ini
index dfd7c5acc..6668574b1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -32,6 +32,7 @@ deps =
     Pillow
     python-magic
     docutils
+    langdetect
     git+https://git.entrouvert.org/debian/django-ckeditor.git
     django111: django>=1.11,<1.12
     django22: django>=2.2,<2.3
diff --git a/wcs/qommon/templatetags/qommon.py b/wcs/qommon/templatetags/qommon.py
index 462759a79..b1ef3ed54 100644
--- a/wcs/qommon/templatetags/qommon.py
+++ b/wcs/qommon/templatetags/qommon.py
@@ -26,6 +26,12 @@ import random
 import pyproj
 from pyproj import Geod
 
+try:
+    import langdetect
+    from langdetect.lang_detect_exception import LangDetectException
+except ImportError:
+    langdetect = None
+
 from django import template
 from django.template import defaultfilters
 from django.utils import dateparse
@@ -440,6 +446,16 @@ def has_role(user, role_name):
     return False
 
 
+@register.filter
+def language_detect(value):
+    if langdetect is None:
+        return ''
+    try:
+        return langdetect.detect(str(value))
+    except LangDetectException:
+        return ''
+
+
 @register.filter(is_safe=False)
 def phonenumber_fr(value, separator=' '):
     DROMS = ('262', '508', '590', '594', '596')