setup for preview mode with cookie to be picked by reverse proxy

.idea/charasheet.iml

@@ -23,6 +23,7 @@
       <excludeFolder url="file://$MODULE_DIR$/.direnv" />
       <excludeFolder url="file://$MODULE_DIR$/.pytest_cache" />
       <excludeFolder url="file://$MODULE_DIR$/.ruff_cache" />
+      <excludeFolder url="file://$MODULE_DIR$/.venv" />
     </content>
     <orderEntry type="jdk" jdkName="Python 3.11 (charasheet)" jdkType="Python SDK" />
     <orderEntry type="sourceFolder" forTests="false" />

src/charasheet/context_processors.py

@@ -1,5 +1,12 @@
 from django.conf import settings
+from django.core.handlers.wsgi import WSGIRequest
 
 
 def app(_):
     return settings.APP
+
+
+def preview(request: WSGIRequest):
+    return {
+        "preview_enabled": request.session.get("preview", False),
+    }

src/charasheet/middleware.py

@@ -1,4 +1,6 @@
 from django.conf import settings
+from django.core.handlers.wsgi import WSGIRequest
+from django.http import HttpResponse
 
 
 def debug_toolbar_bypass_internal_ips(_) -> bool:
@@ -9,3 +11,31 @@ def debug_toolbar_bypass_internal_ips(_) -> bool:
     This is impossible to predict in a docker/k8s environment so we bypass this check.
     """
     return settings.DEBUG_TOOLBAR
+
+
+class PreviewMiddleware:
+    def __init__(self, get_response):
+        self.get_response = get_response
+
+    def __call__(self, request: WSGIRequest):
+        enable_preview = "enable_preview" in request.GET
+        disable_preview = "disable_preview" in request.GET
+
+        new_value = None
+
+        if enable_preview:
+            new_value = True
+        elif disable_preview:
+            new_value = False
+
+        if new_value is not None:
+            request.session["preview"] = new_value
+
+        response: HttpResponse = self.get_response(request)
+
+        if new_value is True:
+            response.set_cookie("preview", "enabled")
+        elif new_value is False:
+            response.delete_cookie("preview")
+
+        return response

src/charasheet/settings.py

@@ -97,6 +97,7 @@ MIDDLEWARE = [
     "django.contrib.messages.middleware.MessageMiddleware",
     "django.middleware.clickjacking.XFrameOptionsMiddleware",
     "django_htmx.middleware.HtmxMiddleware",
+    "charasheet.middleware.PreviewMiddleware",
 ]
 if DEBUG_TOOLBAR:
     MIDDLEWARE.insert(0, "debug_toolbar.middleware.DebugToolbarMiddleware")
@@ -117,6 +118,7 @@ TEMPLATES = [
                 "django.contrib.auth.context_processors.auth",
                 "django.contrib.messages.context_processors.messages",
                 "charasheet.context_processors.app",
+                "charasheet.context_processors.preview",
             ],
         },
     },

src/common/templates/common/footer.html

@@ -1,7 +1,13 @@
 <footer class="bg-light mt-auto">
     <div class="container text-muted pt-2 pb-2 d-flex justify-content-between">
         <span>
-            Version : {{ build.describe }} &bull; {{ build.date }}
+            Version : {{ build.describe }}
+            &bull; {{ build.date }}
+            {% if preview_enabled %}
+                &bull; <a class="text-muted" href="?disable_preview">Disable preview</a>
+            {% else %}
+                &bull; <a class="text-muted" href="?enable_preview">Enable preview</a>
+            {% endif %}
         </span>
         <div>
             <a href="https://github.com/Crocmagnon/charasheet" class="text-muted"><i class="fa-brands fa-github"></i></a>