Remove unnecessary error handler; align and complete error templates.

biscuit/core/templates/core/error.html → biscuit/core/templates/403.html

 {% extends "core/base.html" %}
-{% load bootstrap4 i18n staticfiles %}
+{% load i18n %}
+
+{% block page_title %}
+ {% blocktrans %}Forbidden{% endblocktrans %}
+{% endblock %}
 
 {% block content %}
  <div class="jumbotron jumbotron-fluid">
   <div class="container">
-   <h1>{{ status }} - {{ caption }}</h1>
    <p class="lead">
-    {{ message }}
+     {{ exception|default:_('You are not allowed to access the requested page or object.') }}
    </p>
    <hr />
    <p>
     {% blocktrans %}
-     If you think this is an error in BiscuIT, please contact one of your
-     site administrators:
+     If you think this is an error in BiscuIT, please contact your site
+     administrators.
     {% endblocktrans %}
    </p>
    <ul>

biscuit/core/templates/404.html

+{% extends "core/base.html" %}
+{% load i18n %}
+
+{% block page_title %}
+ {% blocktrans %}Not found{% endblocktrans %}
+{% endblock %}
+
+{% block content %}
+ <div class="jumbotron jumbotron-fluid">
+  <div class="container">
+   <p class="lead">
+     {{ exception|default:_('The requested page or object was not found.') }}
+   </p>
+   <hr />
+   <p>
+    {% blocktrans %}
+     If you were redirected by a link on an external page,
+     it is possible that that link was outdated.
+    {% endblocktrans %}
+    {% blocktrans %}
+     If you think this is an error in BiscuIT, please contact your site
+     administrators.
+    {% endblocktrans %}
+   </p>
+   <ul>
+    {% for admin in ADMINS %}
+     <li>
+      {{ admin.0 }}
+      &lt;
+      <a href="mailto:{{ admin.1 }}">
+       {{ admin.1 }}
+      </a>
+      &gt;
+     </li>
+    {% endfor %}
+   </ul>
+  </div>
+ </div>
+{% endblock %}

biscuit/core/templates/500.html

+{% extends "core/base.html" %}
+{% load i18n %}
+
+{% block page_title %}
+ {% blocktrans %}Internal Server Error{% endblocktrans %}
+{% endblock %}
+
+{% block content %}
+ <div class="jumbotron jumbotron-fluid">
+  <div class="container">
+   <p class="lead">
+     {% blocktrans %}
+      An unexpected error has occured.
+     {% endblocktrans %}
+   </p>
+   <hr />
+   <p>
+    {% blocktrans %}
+     Your site administrators will automatically be notified about this
+     error.
+    {% endblocktrans %}
+   </p>
+  </div>
+ </div>
+{% endblock %}

biscuit/core/templates/503.html

 {% extends "core/base.html" %}
-{% load bootstrap4 i18n staticfiles %}
+{% load i18n %}
+
+{% block page_title %}
+ {% blocktrans %}Maintenance mode{% endblocktrans %}
+{% endblock %}
 
 {% block content %}
  <div class="jumbotron jumbotron-fluid">
   <div class="container">
-   <h1>503 - Maintenance mode</h1>
    <p class="lead">
     {% blocktrans %}
      The maintenance mode is currently enabled. Please try again later.

biscuit/core/urls.py

@@ -30,10 +30,6 @@ urlpatterns = [
     path('__i18n__/', include('django.conf.urls.i18n'))
 ]
 
-# Custom error pages
-handler404 = views.error_handler(404)
-handler500 = views.error_handler(500)
-
 # Serve javascript-common if in development
 if settings.DEBUG:
     urlpatterns += static('/javascript/',

biscuit/core/views.py

@@ -18,25 +18,6 @@ def index(request: HttpRequest) -> HttpResponse:
     return render(request, 'core/index.html', context)
 
 
-def error_handler(status: int) -> Callable[..., HttpResponse]:
-    def real_handler(request: HttpRequest, *args, **kwargs) -> HttpResponse:
-        context = {}
-
-        context['status'] = status
-
-        if status == 404:
-            context['message'] = _(
-                'This page does not exist. If you were redirected by a link on an external page, it is possible that that link was outdated.')
-            context['caption'] = _('Page not found')
-        elif status == 500:
-            context['caption'] = _('Internal server error')
-            context['message'] = _('An unexpected error has occurred.')
-
-        return render(request, 'core/error.html', context, status=status)
-
-    return real_handler
-
-
 @login_required
 def persons(request: HttpRequest) -> HttpResponse:
     context = {}