correct pagination with filters on using custom tag

custom tag copied from https://stackoverflow.com/a/17068299


Former-commit-id: 7fc0c4824eb0d75e0f4b01d3589cba92f6af490d

ippisite/ippidb/templates/compound_list.html

 {% extends "base.html" %}
-
+{% load customtags %}
     
 {% block title %}compound{% endblock %}
 
@@ -46,7 +46,7 @@
   <ul class="pagination justify-content-end">
     {% if compounds.has_previous %}
     <li class="page-item">
-     <a class="page-link" href="?page={{ compounds.previous_page_number }}" tabindex="-1">Previous</a>
+     <a class="page-link" href="?{% url_replace request 'page' compounds.previous_page_number  %}" tabindex="-1">Previous</a>
     </li>
     {% endif %}
 
@@ -56,7 +56,7 @@
 
     {% if compounds.has_next %}
     <li class="page-item">
-     <a class="page-link" href="?page={{ compounds.next_page_number }}" tabindex="-1">Next</a>
+     <a class="page-link" href="?{% url_replace request 'page' compounds.next_page_number  %}" tabindex="-1">Next</a>
     </li>
     {% endif %}
   </ul>

ippisite/ippidb/templatetags/customtags.py

+from django import template
+
+register = template.Library()
+
+@register.simple_tag
+def url_replace(request, field, value):
+    dict_ = request.GET.copy()
+    dict_[field] = value
+    return dict_.urlencode()