Add ISO 639 part 3 validator for model field lang

heidegger_index/migrations/0013_lemma_lang.py

@@ -1,9 +1,11 @@
-# Generated by Django 4.2.9 on 2024-02-09 08:50
+# Generated by Django 4.1 on 2024-02-11 23:08
 
 from django.db import migrations, models
+import heidegger_index.validators
 
 
 class Migration(migrations.Migration):
+
     dependencies = [
         ("heidegger_index", "0012_lemma_zeno"),
     ]
@@ -12,6 +14,10 @@ class Migration(migrations.Migration):
         migrations.AddField(
             model_name="lemma",
             name="lang",
-            field=models.CharField(max_length=3, null=True),
+            field=models.CharField(
+                max_length=3,
+                null=True,
+                validators=[heidegger_index.validators.validate_iso639_3_lang],
+            ),
         ),
     ]

heidegger_index/models.py

@@ -13,7 +13,7 @@
     slugify,
     contains_page_range,
 )
-from heidegger_index.validators import validate_gnd, validate_zeno
+from heidegger_index.validators import validate_gnd, validate_zeno, validate_iso639_3_lang
 
 
 class Work(models.Model):
@@ -80,7 +80,7 @@ class Lemma(models.Model):
     related = models.ManyToManyField("self", symmetrical=True)
     type = models.CharField(max_length=1, null=True, choices=LemmaType.list_choices())
     description = models.TextField(null=True)
-    lang = models.CharField(max_length=3, null=True)
+    lang = models.CharField(max_length=3, null=True, validators=[validate_iso639_3_lang])
 
     urn = models.URLField(
         MetadataType.URN.label,

heidegger_index/validators.py

@@ -1,5 +1,7 @@
 from django.core.exceptions import ValidationError
 from .constants import MetadataType
+from iso639 import Lang
+from iso639.exceptions import InvalidLanguageValue
 
 import re
 
@@ -56,3 +58,13 @@ def validate_dk(value: int | str):
 
 def validate_zeno(value: str | int):
     validate_simple_regex(value, ZENO_REGEX, MetadataType.ZENO.label)
+
+
+def validate_iso639_3_lang(value: str):
+    try:
+        lang_code = Lang(value)
+    except InvalidLanguageValue as e:
+        raise ValidationError(e.msg)
+
+    if lang_code.pt3 != value:
+        raise ValidationError(f'"{value}" is not a ISO 639 part 3 language code.')

requirements/production.txt

@@ -20,4 +20,5 @@ aenum==3.*
 django-compressor==4.*
 django-libsass==0.*
 python-decouple==3.*
-lxml==5.*
+lxml==5.*
+iso639-lang