WIP: pagination for search results

web/app/search.py

 from . import solr
 from . import ops
 import pycountry
+import math
 
 search = Blueprint('search', __name__)
 
             year = request.form.get('year')
         else:
             year = None
+        if request.form.get('page') is not None:
+            page = request.form.get('page')
+        else:
+            page = '1'
     else:
         if request.args.get('query') is not None:
             query = request.args.get('query')
             year = request.args.get('year')
         else:
             year = None
+        if request.args.get('page') is not None:
+            page = request.args.get('page')
+        else:
+            page = '1'
     if (query is None and country is None and year is None):
         return redirect(url_for('main.index'))
     else:
-        search_results = solr.query_search(core, sort, query, country, year)
+        search_results = solr.query_search(core, sort, query, country, year, page)
         results = search_results[0]
         num_found = search_results[1]
         year_facet = search_results[2]['year']
                     country_full = pycountry.historic_countries.get(alpha_2=country_facet[i])
                     if country_full is not None:
                         country_facet[i] = country_full
+        # get total number of records
         total_number = solr.get_total_number(core)
-        return render_template('search.html', results=results, num_found=num_found, total_number=total_number, country_facet=country_facet, year_facet=year_facet, query=query, core=core, sort=sort, country=country, year=year)
+        # work out how many pages to display in the pagination
+        num_pages = math.ceil(int(num_found) / 10)
+        raw_pagination = list(range(1, num_pages+1))
+        if int(page) > 5:
+            pagination = raw_pagination[int(page)-5:int(page)+4]
+            #pagination.insert(0,raw_pagination[0])
+            #pagination.append(raw_pagination[len(raw_pagination)-1])
+        else:
+            end = 9-int(page)
+            pagination = raw_pagination[:int(page)+end]
+            #pagination.insert(0,raw_pagination[0])
+            #pagination.append(raw_pagination[len(raw_pagination)-1])
+        # work out page range for display
+        page_end = int(page) * 10
+        page_start = page_end - 9
+        page_end = page_start + (len(results)-1)
+        page_range = str(page_start) + '–' + str(page_end)
+        return render_template('search.html', results=results, num_found=num_found, total_number=total_number, country_facet=country_facet, year_facet=year_facet, query=query, core=core, sort=sort, country=country, year=year, page=page, page_range=page_range, pagination=pagination)
 
 # route for id_search page
 @search.route('/search/id/', methods=['GET'])

web/app/solr.py

 
     return output, num_found, facets
 
-def query_search(core, sort, query, country, year):
+def query_search(core, sort, query, country, year, page):
 
     # assemble parameters for the query string to Solr
     if (sort == 'relevance'):
         field = 'year'
         year_parameter = '&fq=%7B!term%20f%3D' + field + '%7D' + year
 
+    if (page is None or page == 'None'):
+        page_parameter = ''
+    else:
+        start = (int(page) * 10) - 10
+        start = str(start)
+        page_parameter = '&start=' + start + '&rows=10'
+
     # assemble a query string to send to Solr. This uses the Solr hostname from config.env. Solr's query syntax can be found at many sites including https://lucene.apache.org/solr/guide/6_6/the-standard-query-parser.html
-    solrurl = 'http://' + solr_hostname + ':' + solr_port + '/solr/' + core + '/select?q.op=OR&indent=true' + query_parameter + '&wt=json' + sort_parameter + country_parameter + year_parameter + '&facet.field=country&facet.field=year&facet.sort=count&facet.mincount=1&facet=true'
+    solrurl = 'http://' + solr_hostname + ':' + solr_port + '/solr/' + core + '/select?q.op=OR&indent=true' + query_parameter + '&wt=json' + sort_parameter + country_parameter + year_parameter + page_parameter + '&facet.field=country&facet.field=year&facet.sort=count&facet.mincount=1&facet=true'
 
     output = solr_search(solrurl)
 

web/app/templates/search.html

   </div>
 </div>
 
+<div class="text-center">
+  <p>showing {{ page_range }} results of {{ num_found }} found{% if query is not none %} for query '{{ query }}'{% endif %}</p>
+  {% for page_number in pagination %}
+    <a {% if page_number|int == page|int %}class="fs-4"{% endif %} href="{{ url_for('search.basic_search', query=query, sort=sort, country=country, year=year, page=page_number) }}">{{ page_number }}</a>
+  {% endfor %}
+</div>
+
 <div class="row p-3">
   <form action="{{ url_for('search.basic_search') }}" method="POST">
     <input type="hidden" name="query" value="{{ query }}">