Add handy 'add_get_parameters' templatetag

profiles/templates/profiles/profile_list.html

 {% extends 'scipost/_personal_page_base.html' %}
 
 {% load bootstrap %}
+{% load add_get_parameters %}
 
 {% block breadcrumb_items %}
     {{ block.super }}
@@ -15,6 +16,7 @@
 <div class="row">
   <div class="col-12">
     <p>
+      View Profiles <a href="{% add_get_parameters contributor=True %}">with</a> or <a href="{% add_get_parameters contributor=False %}">without</a> an associated Contributor
       <ul class="list-inline">
 	<li class="list-inline-item">
 	  <a href="{% url 'profiles:profiles' %}">View all</a> or view by discipline/subject area:

profiles/views.py

@@ -85,6 +85,10 @@ class ProfileListView(PermissionsMixin, ListView):
             queryset = queryset.filter(discipline=self.request.GET['discipline'].lower())
             if self.request.GET.get('expertise', None):
                 queryset = queryset.filter(expertises__contains=[self.request.GET['expertise']])
+        if self.request.GET.get('contributor', None) == 'False':
+            queryset = queryset.filter(contributor=None)
+        elif self.request.GET.get('contributor', None) == 'True':
+            queryset = queryset.exclude(contributor=None)
         return queryset
 
     def get_context_data(self, **kwargs):

scipost/templatetags/add_get_parameters.py

+__copyright__ = "Copyright 2016-2018, Stichting SciPost (SciPost Foundation)"
+__license__ = "AGPL v3"
+
+
+from django import template
+
+register = template.Library()
+
+
+@register.simple_tag(takes_context=True)
+def add_get_parameters(context, **kwargs):
+    parameters = context['request'].GET.copy()
+    for k, v in kwargs.items():
+        if v is not None:
+            parameters[k] = v
+    if parameters:
+        params = '?'
+        for k, v in parameters.items():
+            params += '&%s=%s' % (k, v)
+        return params.replace('?&', '?')
+    return ''