feat(templates): allow disabling validation

Add new parameter `disable_template_validation` on template upload. This
can be used if you cannot provide correct sample data upon upload, and/or
the magic validation does not work.

USAGE.md

@@ -196,6 +196,18 @@ in the example above would become something like:
 ...     ),
 ```
 
+### Disabling template validation
+
+Sometimes, templates contain advanced syntax that cannot be correctly validated
+by the automatic mechanism. If you at the same time are also unable to provide
+usable sample data, you can disable template validation entirely.
+
+Please note that in this case, templates will be accepted that may cause errors
+when actually used, so make sure to test them after uploading!
+
+To disable template validation, pass in the additional parameter
+`disable_template_validation` with the value `true` on template upload.
+
 
 ## Merging templates
 

document_merge_service/api/serializers.py

@@ -27,6 +27,9 @@ def __call__(self, serializer_field):
 
 
 class TemplateSerializer(serializers.ModelSerializer):
+    disable_template_validation = serializers.BooleanField(
+        allow_null=True, default=False
+    )
     group = serializers.CharField(allow_null=True, default=CurrentGroupDefault())
     available_placeholders = serializers.ListField(allow_null=True, required=False)
     sample_data = serializers.JSONField(allow_null=True, required=False)
@@ -63,6 +66,12 @@ def _(doc):
         return sorted([x.replace(".[]", "[]") for x in _doc(sample_doc)])
 
     def validate(self, data):
+        if data.pop("disable_template_validation", False):
+            # Some template structures cannot be validated automatically,
+            # or it would be impossible or too much effort to provide accurate
+            # sample data. For those cases, we allow disabling the validation.
+            return data
+
         engine = data.get("engine", self.instance and self.instance.engine)
         template = data.get("template", self.instance and self.instance.template)
 
@@ -108,6 +117,7 @@ class Meta:
             "available_placeholders",
             "sample_data",
             "files",
+            "disable_template_validation",
         )
 
 

document_merge_service/api/tests/test_template.py

@@ -174,6 +174,53 @@ def test_template_create(
         Document(io.BytesIO(response.content))
 
 
+@pytest.mark.parametrize(
+    "status_code, disable_validation",
+    [
+        (
+            status.HTTP_400_BAD_REQUEST,
+            "false",
+        ),
+        (
+            status.HTTP_400_BAD_REQUEST,
+            "",
+        ),
+        (
+            status.HTTP_201_CREATED,
+            "true",
+        ),
+    ],
+)
+def test_disable_validation(
+    db,
+    status_code,
+    admin_client,
+    settings,
+    disable_validation,
+):
+    settings.REQUIRE_AUTHENTICATION = False
+    url = reverse("template-list")
+
+    template_file = django_file("docx-template-syntax.docx")
+    data = {
+        "slug": "test-slug",
+        "template": template_file.file,
+        "engine": models.Template.DOCX_TEMPLATE,
+    }
+    if disable_validation:
+        data["disable_template_validation"] = disable_validation
+
+    response = admin_client.post(url, data=data, format="multipart")
+    assert response.status_code == status_code
+
+    if status_code == status.HTTP_201_CREATED:
+        data = response.json()
+        template_link = data["template"]
+        response = admin_client.get(template_link)
+        assert response.status_code == status.HTTP_200_OK
+        Document(io.BytesIO(response.content))
+
+
 @pytest.mark.parametrize(
     "template_name,available_placeholders,sample_data,files,expect_missing_placeholders,engine,status_code",
     [