Refactor case handling: update URLs and views to support case_number and case_id interchangeably, enhancing backward compatibility and maintainability

atlas/models.py

@@ -1443,6 +1443,13 @@ class CaseDetail(models.Model):
     def __str__(self) -> str:
         return f"{self.case} -> {self.collection}"
 
+
+    def get_case_index(self):
+        """Returns the question index (number) in the collection (0 indexed)"""
+        case_details = list(self.collection.casedetail_set.all().order_by("sort_order"))
+
+        return case_details.index(self)
+
     def get_question_schema(self):
         return json.dumps(self.question_schema)
 

atlas/templates/atlas/collection_case_displaysetup.html

@@ -30,7 +30,7 @@ document.getElementById('save-viewerstate').addEventListener('click', function()
         document.getElementById('viewerstate-save-response').innerHTML = "<span class='text-danger'>Viewer state could not be retrieved.</span>";
         return;
     }
-    fetch("{% url 'atlas:collection_case_displaysetup' casedetail.collection.pk casedetail.case.pk %}", {
+    fetch({% if case_number %}"{% url 'atlas:collection_case_displaysetup' casedetail.collection.pk case_number=case_number %}"{% else %}"{% url 'atlas:collection_case_displaysetup_legacy' casedetail.collection.pk casedetail.case.pk %}"{% endif %}, {
         method: "POST",
         headers: {
             "Content-Type": "application/json",
@@ -47,7 +47,7 @@ document.getElementById('save-viewerstate').addEventListener('click', function()
     });
 });
 document.getElementById('reset-viewerstate').addEventListener('click', function() {
-    fetch("{% url 'atlas:collection_case_displaysetup' casedetail.collection.pk casedetail.case.pk %}", {
+    fetch({% if case_number %}"{% url 'atlas:collection_case_displaysetup' casedetail.collection.pk case_number=case_number %}"{% else %}"{% url 'atlas:collection_case_displaysetup_legacy' casedetail.collection.pk casedetail.case.pk %}"{% endif %}, {
         method: "POST",
         headers: {
             "Content-Type": "application/json",

atlas/templates/atlas/collection_case_view_take.html

@@ -66,9 +66,9 @@
         <div>
 
             {% if question_completed %}
-                <iframe id="viewer" style="width: 100%; height: 100%; border: none; padding: 0px; min-height: 700px" src="/ohif/viewer/dicomjson?url=https://www.penracourses.org.uk{% url 'atlas:collection_case_dicom_json_review' collection.pk case.pk %}"></iframe>
+                <iframe id="viewer" style="width: 100%; height: 100%; border: none; padding: 0px; min-height: 700px" src="/ohif/viewer/dicomjson?url=https://www.penracourses.org.uk{% if case_number %}{% url 'atlas:collection_case_dicom_json_review' collection.pk case_number=case_number %}{% else %}{% url 'atlas:collection_case_dicom_json_review_legacy' collection.pk case.pk %}{% endif %}"></iframe>
             {% else %}
-                <iframe id="viewer" style="width: 100%; height: 100%; border: none; padding: 0px; min-height: 700px" src="/ohif/viewer/dicomjson?url=https://www.penracourses.org.uk{% url 'atlas:collection_case_dicom_json' collection.pk case.pk %}"></iframe>
+                <iframe id="viewer" style="width: 100%; height: 100%; border: none; padding: 0px; min-height: 700px" src="/ohif/viewer/dicomjson?url=https://www.penracourses.org.uk{% if case_number %}{% url 'atlas:collection_case_dicom_json' collection.pk case_number=case_number %}{% else %}{% url 'atlas:collection_case_dicom_json_legacy' collection.pk case.pk %}{% endif %}"></iframe>
             {% endif %}
 
         </div>
@@ -77,10 +77,10 @@
 
     {% if collection.show_ohif_viewer_link %}
         <div>
-            {% if question_completed %}
-                <a target="_blank" href="/ohif/viewer/dicomjson?url=https://www.penracourses.org.uk{% url 'atlas:collection_case_dicom_json_review' collection.pk case.pk %}" title="Click to open the case in the advanced viewer. This will open in a new tab/window."><button class="viewer"><i class="bi bi-collection"></i> Launch advanced viewer.</button></a>
+                {% if question_completed %}
+                <a target="_blank" href="/ohif/viewer/dicomjson?url=https://www.penracourses.org.uk{% if case_number %}{% url 'atlas:collection_case_dicom_json_review' collection.pk case_number=case_number %}{% else %}{% url 'atlas:collection_case_dicom_json_review_legacy' collection.pk case.pk %}{% endif %}" title="Click to open the case in the advanced viewer. This will open in a new tab/window."><button class="viewer"><i class="bi bi-collection"></i> Launch advanced viewer.</button></a>
             {% else %}
-                <a target="_blank" href="/ohif/viewer/dicomjson?url=https://www.penracourses.org.uk{% url 'atlas:collection_case_dicom_json' collection.pk case.pk %}" title="Click to open the case in the advanced viewer. This will open in a new tab/window."><button class="viewer"><i class="bi bi-collection"></i> Launch advanced viewer.</button></a>
+                <a target="_blank" href="/ohif/viewer/dicomjson?url=https://www.penracourses.org.uk{% if case_number %}{% url 'atlas:collection_case_dicom_json' collection.pk case_number=case_number %}{% else %}{% url 'atlas:collection_case_dicom_json_legacy' collection.pk case.pk %}{% endif %}" title="Click to open the case in the advanced viewer. This will open in a new tab/window."><button class="viewer"><i class="bi bi-collection"></i> Launch advanced viewer.</button></a>
             {% endif %}
         </div>
     {% endif %}

atlas/templates/atlas/partials/_prior_card.html

@@ -24,9 +24,14 @@
                     <a href="{% url 'atlas:case_detail' case.id %}" class="btn btn-sm btn-outline-primary">View case</a>
                 </div>
 
-                {% if not added %}
-                    <form class="row g-2" hx-post="{% url 'atlas:collection_case_priors' collection.id casedetail.case.pk %}"
-                          hx-target="#prior-card-{{case.id}}" hx-swap="outerHTML">
+                                {% if not added %}
+                                        <form class="row g-2"
+                                                    {% if case_number %}
+                                                        hx-post="{% url 'atlas:collection_case_priors' collection.id case_number=case_number %}"
+                                                    {% else %}
+                                                        hx-post="{% url 'atlas:collection_case_priors_legacy' collection.id casedetail.case.pk %}"
+                                                    {% endif %}
+                                                    hx-target="#prior-card-{{case.id}}" hx-swap="outerHTML">
                         {% csrf_token %}
                         <input type="hidden" name="prior_case_id" value="{{case.id}}" />
                         <div class="col-12">
@@ -44,8 +49,13 @@
                         </div>
                     </form>
                 {% else %}
-                    <form hx-post="{% url 'atlas:collection_case_priors' collection.id casedetail.case.pk %}"
-                          hx-target="#prior-card-{{case.id}}" hx-swap="outerHTML">
+                                        <form
+                                                {% if case_number %}
+                                                    hx-post="{% url 'atlas:collection_case_priors' collection.id case_number=case_number %}"
+                                                {% else %}
+                                                    hx-post="{% url 'atlas:collection_case_priors_legacy' collection.id casedetail.case.pk %}"
+                                                {% endif %}
+                                                hx-target="#prior-card-{{case.id}}" hx-swap="outerHTML">
                         {% csrf_token %}
                         <input type="hidden" name="remove" value="{{case.id}}" />
                         <div class="mb-2 small text-muted">Current relation: <strong>{{relation}}</strong></div>

atlas/templates/atlas/partials/_viewing_case_as_part_of_collection.html

@@ -2,7 +2,7 @@
     <div class="d-flex justify-content-between align-items-center mb-3">
         <div>
             {% if previous %}
-                <a class="btn btn-outline-secondary btn-sm" href="{% url nav_link_view collection.id previous.id %}">&larr; Previous</a>
+                <a class="btn btn-outline-secondary btn-sm" href="{% url nav_link_view collection.id case_number|add:-1 %}">&larr; Previous</a>
             {% endif %}
         </div>
         <div class="text-center">
@@ -14,7 +14,7 @@
         </div>
         <div>
             {% if next %}
-                <a class="btn btn-outline-secondary btn-sm" href="{% url nav_link_view collection.id next.id %}">Next &rarr;</a>
+                <a class="btn btn-outline-secondary btn-sm" href="{% url nav_link_view collection.id case_number|add:1 %}">Next &rarr;</a>
             {% endif %}
         </div>
 

atlas/templates/atlas/partials/casedetails_management_links.html

@@ -1,14 +1,14 @@
     <div class="btn-group btn-group-sm me-2" role="group" aria-label="management-actions">
-        <a class="btn btn-outline-secondary" href="{% url 'atlas:collection_case_displaysetup' casedetail.collection.pk casedetail.case.pk %}" title="Setup default display">
+        <a class="btn btn-outline-secondary" href="{% url 'atlas:collection_case_displaysetup' casedetail.collection.pk casedetail.get_case_index %}" title="Setup default display">
             <i class="bi bi-display"></i>
         </a>
 
-        <a class="btn btn-outline-secondary" href="{% url 'atlas:collection_case_details' casedetail.collection.pk casedetail.case.pk %}" title="Case details">
+        <a class="btn btn-outline-secondary" href="{% url 'atlas:collection_case_details' casedetail.collection.pk casedetail.get_case_index %}" title="Case details">
             <i class="bi bi-info-square"></i>
         </a>
 
         {% if collection.collection_type == "QUE" %}
-            <a class="btn btn-outline-secondary" href='{% url "atlas:collection_case_questions" casedetail.collection.pk casedetail.case.pk %}' title="Manage questions">
+            <a class="btn btn-outline-secondary" href='{% url "atlas:collection_case_questions" casedetail.collection.pk casedetail.get_case_index %}' title="Manage questions">
                 {% if casedetail.question_schema %}
                     <i class="bi bi-question-square text-success"></i>
                 {% else %}

atlas/urls.py

@@ -168,30 +168,56 @@ urlpatterns = [
     ),
     path("exam/<int:pk>/groups", views.ExamGroupsUpdate.as_view(), name="exam_groups_edit"),
     path(
-        "collection/<int:exam_id>/case/<int:case_id>/details",
+        "collection/<int:exam_id>/case/<int:case_number>/details",
         views.collection_case_details,
         name="collection_case_details",
     ),
+    # Backwards-compatible redirect from legacy case_id-style URLs
     path(
-        "collection/<int:exam_id>/case/<int:case_id>/questions",
+        "collection/<int:exam_id>/case/<int:case_id>/details",
+        views.redirect_collection_case_details_by_id,
+        name="collection_case_details_legacy",
+    ),
+    path(
+        "collection/<int:exam_id>/case/<int:case_number>/questions",
         views.collection_case_questions,
         name="collection_case_questions",
     ),
     path(
-        "collection/<int:exam_id>/case/<int:case_id>/priors",
+        "collection/<int:exam_id>/case/<int:case_id>/questions",
+        views.redirect_collection_case_questions_by_id,
+        name="collection_case_questions_legacy",
+    ),
+    path(
+        "collection/<int:exam_id>/case/<int:case_number>/priors",
         views.collection_case_priors,
         name="collection_case_priors",
     ),
     path(
-        "collection/<int:exam_id>/case/<int:case_id>/dicom_json",
+        "collection/<int:exam_id>/case/<int:case_id>/priors",
+        views.redirect_collection_case_priors_by_id,
+        name="collection_case_priors_legacy",
+    ),
+    path(
+        "collection/<int:exam_id>/case/<int:case_number>/dicom_json",
         views.collection_case_dicom_json,
         name="collection_case_dicom_json",
     ),
     path(
-        "collection/<int:exam_id>/case/<int:case_id>/dicom_json/review",
+        "collection/<int:exam_id>/case/<int:case_id>/dicom_json",
+        views.redirect_collection_case_dicom_json_by_id,
+        name="collection_case_dicom_json_legacy",
+    ),
+    path(
+        "collection/<int:exam_id>/case/<int:case_number>/dicom_json/review",
         views.collection_case_dicom_json_review,
         name="collection_case_dicom_json_review",
     ),
+    path(
+        "collection/<int:exam_id>/case/<int:case_id>/dicom_json/review",
+        views.redirect_collection_case_dicom_json_review_by_id,
+        name="collection_case_dicom_json_review_legacy",
+    ),
     path(
         "collection/<int:exam_id>/question_schemas",
         views.collection_question_schemas,
@@ -272,26 +298,52 @@ urlpatterns = [
         views.collection_case_view,
         name="collection_case_view",
     ),
+    # legacy path that used case PK; redirect to canonical case_number URL
     path(
-        "collection/<int:collection_id>/<int:case_id>/display_setup",
+        "collection/<int:pk>/<int:case_id>",
+        views.redirect_collection_case_view_by_id,
+        name="collection_case_view_legacy",
+    ),
+    path(
+        "collection/<int:collection_id>/<int:case_number>/display_setup",
         views.collection_case_displaysetup,
         name="collection_case_displaysetup",
     ),
+    path(
+        "collection/<int:collection_id>/<int:case_id>/display_setup",
+        views.redirect_collection_case_displaysetup_by_id,
+        name="collection_case_displaysetup_legacy",
+    ),
     path(
         "collection/<int:pk>/<int:case_number>/take/<int:cid>/<str:passcode>",
         views.collection_case_view_take,
         name="collection_case_view_take",
     ),
+    path(
+        "collection/<int:pk>/<int:case_id>/take/<int:cid>/<str:passcode>",
+        views.redirect_collection_case_view_take_by_id,
+        name="collection_case_view_take_legacy",
+    ),
     path(
         "collection/<int:pk>/<int:case_number>/take/",
         views.collection_case_view_take_user,
         name="collection_case_view_take_user",
     ),
+    path(
+        "collection/<int:pk>/<int:case_id>/take/",
+        views.redirect_collection_case_view_take_user_by_id,
+        name="collection_case_view_take_user_legacy",
+    ),
     path(
         "collection/<int:pk>/<int:case_number>/take/answers",
         views.collection_case_view_take_user_answers,
         name="collection_case_view_take_user_answers",
     ),
+    path(
+        "collection/<int:pk>/<int:case_id>/take/answers",
+        views.redirect_collection_case_view_take_user_answers_by_id,
+        name="collection_case_view_take_user_answers_legacy",
+    ),
     path(
         "collection/<int:pk>/json_edit",
         views.GenericExamViews.exam_json_edit,

atlas/views.py

@@ -2755,10 +2755,101 @@ def collection_take_start(request, pk, cid=None, passcode=None):
             )
 
 
+def _case_number_for_collection_and_caseid(collection_pk, case_id):
+    """Helper: given a collection PK and a case PK, return the case index (case_number).
+
+    Raises Http404 if the case is not found in the collection.
+    """
+    collection = get_object_or_404(CaseCollection, pk=collection_pk)
+    try:
+        # attempt to resolve the case object (may raise Http404)
+        case_obj = get_case_for_case_detail(case_id)
+    except Http404:
+        raise
+    try:
+        return collection.get_index_of_case(case_obj)
+    except ValueError:
+        raise Http404(f"Case {case_id} not in collection {collection_pk}")
+
+
+@login_required
+def redirect_collection_case_details_by_id(request, exam_id, case_id):
+    case_number = _case_number_for_collection_and_caseid(exam_id, case_id)
+    return redirect("atlas:collection_case_details", exam_id=exam_id, case_number=case_number)
+
+
+@login_required
+def redirect_collection_case_questions_by_id(request, exam_id, case_id):
+    case_number = _case_number_for_collection_and_caseid(exam_id, case_id)
+    return redirect("atlas:collection_case_questions", exam_id=exam_id, case_number=case_number)
+
+
+@login_required
+def redirect_collection_case_priors_by_id(request, exam_id, case_id):
+    case_number = _case_number_for_collection_and_caseid(exam_id, case_id)
+    return redirect("atlas:collection_case_priors", exam_id=exam_id, case_number=case_number)
+
+
+@login_required
+def redirect_collection_case_dicom_json_by_id(request, exam_id, case_id):
+    case_number = _case_number_for_collection_and_caseid(exam_id, case_id)
+    return redirect("atlas:collection_case_dicom_json", exam_id=exam_id, case_number=case_number)
+
+
+@login_required
+def redirect_collection_case_dicom_json_review_by_id(request, exam_id, case_id):
+    case_number = _case_number_for_collection_and_caseid(exam_id, case_id)
+    return redirect("atlas:collection_case_dicom_json_review", exam_id=exam_id, case_number=case_number)
+
+
+@login_required
+def redirect_collection_case_view_by_id(request, pk, case_id):
+    case_number = _case_number_for_collection_and_caseid(pk, case_id)
+    return redirect("atlas:collection_case_view", pk=pk, case_number=case_number)
+
+
+@login_required
+def redirect_collection_case_displaysetup_by_id(request, collection_id, case_id):
+    case_number = _case_number_for_collection_and_caseid(collection_id, case_id)
+    return redirect("atlas:collection_case_displaysetup", collection_id=collection_id, case_number=case_number)
+
+
+@login_required
+def redirect_collection_case_view_take_by_id(request, pk, case_id, cid, passcode):
+    case_number = _case_number_for_collection_and_caseid(pk, case_id)
+    return redirect("atlas:collection_case_view_take", pk=pk, case_number=case_number, cid=cid, passcode=passcode)
+
+
+@login_required
+def redirect_collection_case_view_take_user_by_id(request, pk, case_id):
+    case_number = _case_number_for_collection_and_caseid(pk, case_id)
+    return redirect("atlas:collection_case_view_take_user", pk=pk, case_number=case_number)
+
+
+@login_required
+def redirect_collection_case_view_take_user_answers_by_id(request, pk, case_id):
+    case_number = _case_number_for_collection_and_caseid(pk, case_id)
+    return redirect("atlas:collection_case_view_take_user_answers", pk=pk, case_number=case_number)
+
+
+
 @user_is_collection_author_or_atlas_editor
 def collection_case_priors(request, exam_id, case_id):
-    casedetail = CaseDetail.objects.get(case=case_id, collection=exam_id)
-    collection = casedetail.collection
+    # Support either case_number (index) or case_id (case PK) in the URL/kwargs.
+    # Backwards compatibility: callers may pass case_id; prefer case_number when present.
+    casedetail = None
+    collection = None
+    # Try treating the parameter as a case PK first, falling back to case index.
+    try:
+        casedetail = CaseDetail.objects.get(case=case_id, collection=exam_id)
+        collection = casedetail.collection
+    except Exception:
+        collection = get_object_or_404(CaseCollection, pk=exam_id)
+        try:
+            case_obj = collection.get_case_by_index(int(case_id))
+            casedetail = CaseDetail.objects.get(case=case_obj, collection=collection)
+        except Exception:
+            raise Http404("Case not found in collection")
 
     if request.htmx:
         # Ensure we can render the updated single-card partial and return it so HTMX
@@ -2892,9 +2983,17 @@ def collection_case_priors(request, exam_id, case_id):
 
 @user_is_collection_author_or_atlas_editor
 def collection_case_questions(request, exam_id, case_id):
-    casedetail = CaseDetail.objects.get(case=case_id, collection=exam_id)
-
-    collection = casedetail.collection
+    # Support either case_number (index) or case_id (case PK)
+    try:
+        casedetail = CaseDetail.objects.get(case=case_id, collection=exam_id)
+        collection = casedetail.collection
+    except Exception:
+        collection = get_object_or_404(CaseCollection, pk=exam_id)
+        try:
+            case_obj = collection.get_case_by_index(int(case_id))
+            casedetail = CaseDetail.objects.get(case=case_obj, collection=collection)
+        except Exception:
+            raise Http404("Case not found in collection")
 
     if not collection.collection_type == "QUE":
         raise Http404("Collection not in question mode")
@@ -3005,9 +3104,19 @@ def collection_case_questions(request, exam_id, case_id):
 
 @user_is_collection_author_or_atlas_editor
 def collection_case_details(request, exam_id, case_id):
-    casedetail = CaseDetail.objects.get(case=case_id, collection=exam_id)
-
-    collection = casedetail.collection
+    # Accept either case_number (index into collection) or case_id (case PK).
+    casedetail = None
+    collection = None
+    try:
+        casedetail = CaseDetail.objects.get(case=case_id, collection=exam_id)
+        collection = casedetail.collection
+    except Exception:
+        collection = get_object_or_404(CaseCollection, pk=exam_id)
+        try:
+            case_obj = collection.get_case_by_index(int(case_id))
+            casedetail = CaseDetail.objects.get(case=case_obj, collection=collection)
+        except Exception:
+            raise Http404("Case not found in collection")
 
     if request.method == "POST":
         form = CaseDetailForm(request.POST, instance=casedetail)
@@ -3303,12 +3412,14 @@ def collection_case_view_take_answers(
     )
 
 
-def collection_case_view_take_user(request, pk: int, case_number: int):
-    return collection_case_view_take(request, pk, case_number)
+def collection_case_view_take_user(request, pk, case_number=None, case_id=None):
+    # Accept either case_number (index) or case_id (case PK) and forward both to
+    # the handler. This allows URLs that use either name to keep working.
+    return collection_case_view_take(request, pk, case_number=case_number, cid=None, passcode=None, case_id=case_id)
 
 
 def collection_case_view_take(
-    request, pk: int, case_number: int, cid=None, passcode=None
+    request, pk, case_number=None, cid=None, passcode=None, case_id=None
 ):
     """
     Displays the page from which the user takes a case in the collection
@@ -3328,6 +3439,21 @@ def collection_case_view_take(
     """
     collection = get_object_or_404(CaseCollection, pk=pk)
 
+    # If caller provided a case_id (case PK) instead of a case_number (index),
+    # translate it into the index used by collection.get_case_by_index().
+    if case_id is not None and case_number is None:
+        try:
+            case_obj = get_case_for_case_detail(case_id)
+        except Http404:
+            raise
+        try:
+            case_number = collection.get_index_of_case(case_obj)
+        except ValueError:
+            raise Http404(f"Case {case_id} not in collection {pk}")
+    # Ensure we have a case_number to work with
+    if case_number is None:
+        raise Http404("No case specified")
+
     form = None
     answer: None | CidReportAnswer | UserReportAnswer = None
 
@@ -3567,7 +3693,7 @@ def collection_case_view_take(
 
 
 @user_is_collection_author_or_atlas_editor
-def collection_case_view(request, pk, case_number):
+def collection_case_view(request, pk, case_number=None, case_id=None):
     """Edit/management overview of the case (as part of the collection)
 
     Args:
@@ -3583,6 +3709,19 @@ def collection_case_view(request, pk, case_number):
     """
     collection = get_object_or_404(CaseCollection, pk=pk)
 
+    # Support either case_number (index) or case_id (case PK) in the URL/kwargs.
+    if case_id is not None and case_number is None:
+        try:
+            case_obj = get_case_for_case_detail(case_id)
+        except Http404:
+            raise
+        try:
+            case_number = collection.get_index_of_case(case_obj)
+        except ValueError:
+            raise Http404(f"Case {case_id} not in collection {pk}")
+    if case_number is None:
+        raise Http404("No case specified")
+
     form = None
     answer = None
 
@@ -3635,8 +3774,18 @@ def use_dates_as_descriptions(request, pk):
 def collection_case_dicom_json_review(request, exam_id, case_id):
     return collection_case_dicom_json(request, exam_id, case_id, review=True)
 
+
 def collection_case_dicom_json(request, exam_id, case_id, review=False):
-    casedetail = CaseDetail.objects.get(case=case_id, collection=exam_id)
+    # Support either case_number (index) or case_id (case PK)
+    try:
+        casedetail = CaseDetail.objects.get(case=case_id, collection=exam_id)
+    except Exception:
+        collection = get_object_or_404(CaseCollection, pk=exam_id)
+        try:
+            case_obj = collection.get_case_by_index(int(case_id))
+            casedetail = CaseDetail.objects.get(case=case_obj, collection=collection)
+        except Exception:
+            raise Http404("Case not found in collection")
 
     if review:
         priors = casedetail.caseprior_set.exclude(prior_visibility="NO")
@@ -4517,12 +4666,26 @@ def series_bulk_delete(request):
 
 @user_is_collection_author_or_atlas_editor
 @csrf_exempt  # Only if you have CSRF issues; otherwise, keep CSRF protection
-def collection_case_displaysetup(request, collection_id, case_id):
+def collection_case_displaysetup(request, collection_id, case_number=None, case_id=None):
     """
     View to set up the display options for a specific case in a collection.
     This can include setting which series to display, annotations, etc.
     """
-    casedetail = get_object_or_404(CaseDetail, case__pk=case_id, collection__pk=collection_id)
+    # Accept either case_number (index into collection) or case_id (case PK).
+    casedetail = None
+    try:
+        # If a case_id was passed explicitly, try that first
+        if case_id is not None:
+            casedetail = get_object_or_404(CaseDetail, case__pk=case_id, collection__pk=collection_id)
+        else:
+            # Otherwise the route most likely supplied case_number; try resolving by index
+            collection = get_object_or_404(CaseCollection, pk=collection_id)
+            case_obj = collection.get_case_by_index(int(case_number))
+            casedetail = CaseDetail.objects.get(case=case_obj, collection=collection)
+    except Http404:
+        raise
+    except Exception:
+        raise Http404("Case not found in collection")
 
     if request.method == "POST":
         data = json.loads(request.body.decode("utf-8"))