Url fix (#5472)

* Use urljoin function to construct absolute URL

* Add unit test

InvenTree/InvenTree/helpers_model.py

@@ -3,6 +3,7 @@
 import io
 import logging
 from decimal import Decimal
+from urllib.parse import urljoin
 
 from django.conf import settings
 from django.core.validators import URLValidator
@@ -64,14 +65,7 @@ def construct_absolute_url(*arg, **kwargs):
         # No site URL available, return the relative URL
         return relative_url
 
-    # Strip trailing slash from base url
-    if site_url.endswith('/'):
-        site_url = site_url[:-1]
-
-    if relative_url.startswith('/'):
-        relative_url = relative_url[1:]
-
-    return f"{site_url}/{relative_url}"
+    return urljoin(site_url, relative_url)
 
 
 def get_base_url(**kwargs):

InvenTree/InvenTree/tests.py

@@ -320,6 +320,34 @@ class FormatTest(TestCase):
 class TestHelpers(TestCase):
     """Tests for InvenTree helper functions."""
 
+    def test_absolute_url(self):
+        """Test helper function for generating an absolute URL"""
+
+        base = "https://demo.inventree.org:12345"
+
+        InvenTreeSetting.set_setting('INVENTREE_BASE_URL', base, change_user=None)
+
+        tests = {
+            "": base,
+            "api/": base + "/api/",
+            "/api/": base + "/api/",
+            "api": base + "/api",
+            "media/label/output/": base + "/media/label/output/",
+            "static/logo.png": base + "/static/logo.png",
+            "https://www.google.com": "https://www.google.com",
+            "https://demo.inventree.org:12345/out.html": "https://demo.inventree.org:12345/out.html",
+            "https://demo.inventree.org/test.html": "https://demo.inventree.org/test.html",
+            "http://www.cwi.nl:80/%7Eguido/Python.html": "http://www.cwi.nl:80/%7Eguido/Python.html",
+            "test.org": base + "/test.org",
+        }
+
+        for url, expected in tests.items():
+            # Test with supplied base URL
+            self.assertEqual(InvenTree.helpers_model.construct_absolute_url(url, site_url=base), expected)
+
+            # Test without supplied base URL
+            self.assertEqual(InvenTree.helpers_model.construct_absolute_url(url), expected)
+
     def test_image_url(self):
         """Test if a filename looks like an image."""
         for name in ['ape.png', 'bat.GiF', 'apple.WeBP', 'BiTMap.Bmp']: