fix(subscriptions): handle regex syntax error (#222)

Author: djs0109

app/Entirety/subscriptions/utils.py

@@ -1,12 +1,19 @@
 import re
 import itertools
-
 from filip.clients.ngsi_v2.cb import ContextBrokerClient
 from filip.models import FiwareHeader
-
 from django.conf import settings
 
 
+def safe_compile(pattern):
+    """Attempt to compile a regex pattern safely."""
+    try:
+        return re.compile(pattern)
+    except re.error as e:
+        # Log or handle the error as needed
+        raise re.error(f"Regular expression {pattern} invalid: {e}")
+
+
 def load_attributes(project, data_set):
     attributes = []
     with ContextBrokerClient(
@@ -22,7 +29,7 @@ def load_attributes(project, data_set):
             entity_type = data["entity_type"]
             if entity_type:
                 if type_selector == "type_pattern":
-                    pattern = re.compile(entity_type)
+                    pattern = safe_compile(entity_type)
                     tmp_attrs = itertools.chain.from_iterable(
                         [
                             list(t["attrs"].keys())
@@ -45,9 +52,9 @@ def load_attributes(project, data_set):
                 if entity_id:
                     entities = cb_client.get_entity_list(
                         entity_ids=entity_id if entity_selector == "id" else None,
-                        id_pattern=entity_id
-                        if entity_selector == "id_pattern"
-                        else None,
+                        id_pattern=(
+                            entity_id if entity_selector == "id_pattern" else None
+                        ),
                     )
                     for entity in entities:
                         attributes.extend(cb_client.get_entity_attributes(entity.id))

app/Entirety/subscriptions/views/create.py

@@ -89,42 +89,62 @@ def post(self, request, *args, **kwargs):
         if form.is_valid() and entities_set.is_valid():
             data_set = [entity_form.cleaned_data for entity_form in entities_set]
             # Otherwise choices are empty
-            attributes.fields["attributes"].choices = utils.load_attributes(
-                self.project, data_set
-            )
-            if attributes.is_valid():
-                instance = form.save(commit=False)
+            try:
+                attributes.fields["attributes"].choices = utils.load_attributes(
+                    self.project, data_set
+                )
+                if attributes.is_valid():
+                    instance = form.save(commit=False)
 
-                entities = []
+                    entities = []
 
-                for entity_form in entities_set:
-                    if entity_form.cleaned_data:
-                        entity_selector = entity_form.cleaned_data["entity_selector"]
-                        type_selector = entity_form.cleaned_data["type_selector"]
-                        pattern = EntityPattern(
-                            id=(
-                                entity_form.cleaned_data["entity_id"]
-                                if entity_selector == "id"
-                                else None
-                            ),
-                            idPattern=(
-                                re.compile(entity_form.cleaned_data["entity_id"])
-                                if entity_selector == "id_pattern"
-                                else None
-                            ),
-                            type=(
-                                entity_form.cleaned_data["entity_type"]
-                                if entity_form.cleaned_data["entity_type"]
-                                and type_selector == "type"
-                                else None
-                            ),
-                            typePattern=(
-                                re.compile(entity_form.cleaned_data["entity_type"])
-                                if type_selector == "type_pattern"
-                                else None
-                            ),
-                        )
-                        entities.append(pattern)
+                    for entity_form in entities_set:
+                        if entity_form.cleaned_data:
+                            entity_selector = entity_form.cleaned_data[
+                                "entity_selector"
+                            ]
+                            type_selector = entity_form.cleaned_data["type_selector"]
+                            pattern = EntityPattern(
+                                id=(
+                                    entity_form.cleaned_data["entity_id"]
+                                    if entity_selector == "id"
+                                    else None
+                                ),
+                                idPattern=(
+                                    utils.safe_compile(
+                                        entity_form.cleaned_data["entity_id"]
+                                    )
+                                    if entity_selector == "id_pattern"
+                                    else None
+                                ),
+                                type=(
+                                    entity_form.cleaned_data["entity_type"]
+                                    if entity_form.cleaned_data["entity_type"]
+                                    and type_selector == "type"
+                                    else None
+                                ),
+                                typePattern=(
+                                    utils.safe_compile(
+                                        entity_form.cleaned_data["entity_type"]
+                                    )
+                                    if type_selector == "type_pattern"
+                                    else None
+                                ),
+                            )
+                            entities.append(pattern)
+            except re.error as e:
+                logger.error(
+                    str(
+                        self.request.user.first_name
+                        if self.request.user.first_name
+                        else self.request.user.username
+                    )
+                    + " tried creating the subscription "
+                    + " but failed "
+                    f" in project {self.project.name}"
+                )
+                messages.error(request, e)
+                return self.form_invalid(form)
             with ContextBrokerClient(
                 url=settings.CB_URL,
                 fiware_header=FiwareHeader(