feat:Add CSV download feature for search results

Introduced a new view `download_search_csv` to generate search results as a CSV file. Updated the template to dynamically set the CSV download link with current query parameters. Adjusted the URL configuration to include the route for CSV download.

orp/config/urls.py

@@ -12,6 +12,11 @@
     path("", orp_search_views.search, name="search"),
     # If we choose to have a start page with green button, this is it:
     # path("", core_views.home, name="home"),
+    path(
+        "download_csv/",
+        orp_search_views.download_search_csv,
+        name="download_csv",
+    ),
     path("details/<str:id>", orp_search_views.details, name="details"),
     path("healthcheck/", core_views.health_check, name="healthcheck"),
     path(

orp/orp_search/templates/orp.html

@@ -180,9 +180,23 @@ <h2 class="govuk-fieldset__heading">
         </button>
         <hr class="govuk-section-break govuk-section-break--m govuk-section-break--visible">
         <p class="govuk-body">
-          <a href="#" class="govuk-link govuk-link--no-visited-state govuk-!-float-right">Download search results as CSV
+          <a id="download-csv-link" href="#" class="govuk-link govuk-link--no-visited-state govuk-!-float-right">Download search results as CSV
             file</a>
         </p>
+
+      <script>
+      // Function to get the current query parameters from the address bar
+      function getQueryParameters() {
+          return window.location.search;
+      }
+
+      document.addEventListener('DOMContentLoaded', function() {
+          var csvLink = document.getElementById('download-csv-link');
+          var queryParams = getQueryParameters();
+          var baseURL = '{% url "download_csv" %}';
+          csvLink.href = baseURL + queryParams;
+      });
+    </script>
       </form>
     </div>
 

orp/orp_search/views.py

@@ -1,5 +1,8 @@
+import csv
 import logging
 
+import pandas as pd
+
 from orp_search.public_gateway import PublicGateway, SearchDocumentConfig
 
 from django.conf import settings
@@ -52,6 +55,45 @@ def details(request: HttpRequest, id) -> HttpResponse:
         return render(request, template_name="details.html", context=context)
 
 
+@require_http_methods(["GET"])
+def download_search_csv(request: HttpRequest) -> HttpResponse:
+    search_terms = request.GET.get("query", "")
+    document_type_terms = request.GET.get("document_type", "")
+    publisher_terms = request.GET.getlist("publisher", None)
+    sort_by = request.GET.get("sort", None)
+
+    config = SearchDocumentConfig(
+        search_terms, document_type_terms, dummy=True
+    )
+
+    if publisher_terms:
+        config.publisher_terms = publisher_terms
+
+    if sort_by:
+        config.sort_by = sort_by
+
+    public_gateway = PublicGateway()
+    search_results = public_gateway.search(config)
+
+    # Convert search_results JSON object to DataFrame
+    # (for demonstration purposes)
+    search_results_df = pd.DataFrame(search_results)
+
+    response = HttpResponse(content_type="text/csv")
+    response["Content-Disposition"] = (
+        'attachment; filename="search_results.csv"'
+    )
+
+    # Write the DataFrame to the response
+    writer = csv.writer(response)
+    writer.writerow(search_results_df.columns)  # Write the header
+
+    for _, row in search_results_df.iterrows():
+        writer.writerow(row)
+
+    return response
+
+
 @require_http_methods(["GET"])
 def search(request: HttpRequest) -> HttpResponse:
     """Search view.
@@ -117,7 +159,6 @@ def search(request: HttpRequest) -> HttpResponse:
     if sort_by:
         config.sort_by = sort_by
 
-    # Check if the response is cached
     public_gateway = PublicGateway()
     search_results = public_gateway.search(config)
     context["results_count_total"] = len(search_results)