Ensure the base url ends with a slash

URLs without a trailing slash won't get properly joined by the bot
Adds compatibility with python-discord/bot@bc25bfdf42cdaaba924a7ad6de1dc06a9b381285's changes

The styling of how the regex decorator is constructed was changed to be consisted with the
function validator

2 files changed, 20 insertions, 8 deletions

diff --git a/pydis_site/apps/api/migrations/0069_documentationlink_packagename_validator.py b/pydis_site/apps/api/migrations/0069_documentationlink_validators.py
index 4234e633..347c0e1a 100644
--- a/pydis_site/apps/api/migrations/0069_documentationlink_packagename_validator.py
+++ b/pydis_site/apps/api/migrations/0069_documentationlink_validators.py
@@ -1,7 +1,8 @@
-# Generated by Django 3.0.11 on 2021-03-14 23:22
+# Generated by Django 3.0.11 on 2021-03-26 18:21
 
 import django.core.validators
 from django.db import migrations, models
+import pydis_site.apps.api.models.bot.documentation_link
 
 
 class Migration(migrations.Migration):
@@ -13,6 +14,11 @@ class Migration(migrations.Migration):
     operations = [
         migrations.AlterField(
             model_name='documentationlink',
+            name='base_url',
+            field=models.URLField(help_text='The base URL from which documentation will be available for this project. Used to generate links to various symbols within this package.', validators=[pydis_site.apps.api.models.bot.documentation_link.ends_with_slash_validator]),
+        ),
+        migrations.AlterField(
+            model_name='documentationlink',
             name='package',
             field=models.CharField(help_text='The Python package name that this documentation link belongs to.', max_length=50, primary_key=True, serialize=False, validators=[django.core.validators.RegexValidator(message='Package names can only consist of lowercase a-z letters, digits, and underscores.', regex='^[a-z0-9_]+$')]),
         ),
diff --git a/pydis_site/apps/api/models/bot/documentation_link.py b/pydis_site/apps/api/models/bot/documentation_link.py
index 529d26d1..3dcc71fc 100644
--- a/pydis_site/apps/api/models/bot/documentation_link.py
+++ b/pydis_site/apps/api/models/bot/documentation_link.py
@@ -1,30 +1,36 @@
+from django.core.exceptions import ValidationError
 from django.core.validators import RegexValidator
 from django.db import models
 
 from pydis_site.apps.api.models.mixins import ModelReprMixin
 
-package_name_validator = (
-    RegexValidator(
-        regex=r"^[a-z0-9_]+$",
-        message="Package names can only consist of lowercase a-z letters, digits, and underscores."
-    ),
+package_name_validator = RegexValidator(
+    regex=r"^[a-z0-9_]+$",
+    message="Package names can only consist of lowercase a-z letters, digits, and underscores."
 )
 
 
+def ends_with_slash_validator(string: str) -> None:
+    """Raise a ValidationError if `string` does not end with a slash."""
+    if not string.endswith("/"):
+        raise ValidationError("The entered URL must end with a slash.")
+
+
 class DocumentationLink(ModelReprMixin, models.Model):
     """A documentation link used by the `!docs` command of the bot."""
 
     package = models.CharField(
         primary_key=True,
         max_length=50,
-        validators=package_name_validator,
+        validators=(package_name_validator,),
         help_text="The Python package name that this documentation link belongs to."
     )
     base_url = models.URLField(
         help_text=(
             "The base URL from which documentation will be available for this project. "
             "Used to generate links to various symbols within this package."
-        )
+        ),
+        validators=(ends_with_slash_validator,)
     )
     inventory_url = models.URLField(
         help_text="The URL at which the Sphinx inventory is available for this package."