Export Haystack search results - solr

Question

I am trying to export the results of a user's search. I am using Django + Haystack + Solr to produce the search results. Currently, to create the SearchQuerySet to write out the CSV, I am passing the query parameters from the search results page to the view that produces the CSV and rebuilding the SearchQuerySet there. This is a real pain because the search is pretty complicated, with facets, multiple models, etc, and there are constantly bugs when I make modifications to the SearchForm. It seems like there should be an easy way to just pass the results directly to the export view. Any suggestions?
EDIT
I figured out my own solution and put all the modified code in the answer. Please see below. Hopefully this prevents someone else from banging their head against the wall for a week!

Answer 1

Okay, I finally figured this out myself. I basically had to add a second submit button to the html for my SearchForm and then used javascript to redirect the action to my "search_export" view. Since facets aren't passed along when the form is submitted, I had to get the facets from the request (in the search page template) and pass those to view rather hackishly through the url. The facets then have to be re-evaluated in the view. I will paste all of my code below:
search.html
{% block content %}
<form method="get" action=".">
<!-- Advanced Search Box -->
<div class="row">
<div class="col-lg-12">
<h2 class="text-center">Advanced Search</h2>
<!-- Search Form Fields Here -->
<ul class="list-inline center-block text-center adv-form">
<li>
<p><input type="submit" value="Search"></p>
</li>
<li>
<p><input type="submit" id="export" value="Export Results"></p>
</li>
</ul>
</div>
</div>
<!-- End Advanced Search Box -->
<!-- Search Results are displayed here -->
{% endblock %}
<!-- Search Unique JS -->
{% block js %}
{{ block.super }}
<script>
$(document).ready(function () {
$("#export").click(function() {
$(this).closest("form").attr('action', "{% query_params_getlist request 'selected_facets' as facets %}{% url 'search_export' facets %}");
});
});
</script>
{% endblock %}
<!-- End Search Unique JS -->
urls.py
urlpatterns = patterns('base.views',
# all the other url patterns go here
url(r'^search_export/(?P<selected_facets>\S+)/$', 'search_export', name='search_export'),
)
base_tags.py
#register.assignment_tag
def query_params_getlist(request, param):
params = request.GET.getlist(param)
if len(params) > 0:
query_string = ""
for p in params:
query_string += p + '&'
return query_string
return 'None'
views.py
def search_export(request, selected_facets):
if request.method == 'GET':
form = AdvModelSearchForm(request.GET)
if form.is_valid():
qs = form.search()
#deal with facets
facets = selected_facets.split("&")
for facet in facets:
if ":" not in facet:
continue
field, value = facet.split(":", 1)
if value:
# faceted fields are stored in a hierarchy, so I check for any document with the given facet or its children
control_value = ControlField.objects.filter(pk=qs.query.clean(value))
if control_value:
value_tree = control_value[0].get_descendants(include_self=True)
sq = SQ()
for index, node in enumerate(value_tree):
kwargs = {str("%s" % (field)) : str("%s" % (node.id))}
if index == 0:
sq = SQ(**kwargs)
else:
sq = sq | SQ(**kwargs)
qs = qs.filter(sq)
response = HttpResponse(content_type='text/csv')
response['Content-Disposition'] = 'attachment; filename="search_results.csv"'
writer = csv.writer(response)
titles = []
rows = []
for result in qs:
row = []
row_dict = {}
properties = result.text #IMPT - this field must be a MultiValueField in the Haystack search_indexes.py file or this won't return a list
for each_prop in properties:
prop_pair = each_prop.split(':', 1)
if len(prop_pair) < 2:
continue
prop_name = smart_str(prop_pair[0].strip())
prop_value = smart_str(prop_pair[1].strip())
if not (prop_name in titles):
column_index = len(titles)
titles.append(prop_name)
else:
column_index = titles.index(prop_name)
if column_index in row_dict:
prop_value = row_dict[column_index] + '; ' + prop_value
row_dict[column_index] = prop_value
for i in range(len(titles)):
if i in row_dict:
row.append(row_dict[i])
else:
row.append('')
rows.append(row)
writer.writerow(titles)
for each_row in rows:
writer.writerow(each_row)
return response
return HttpResponseRedirect('/failed_export/')