Added visit page view

Fixes #74

Allows frontend users to submit page views and retrieve segments while
behind a cache or CDN.

Author: kaedroho

src/wagtail_personalisation/adapters.py

@@ -169,7 +169,7 @@ def refresh(self):
 
         self.update_visit_count()
 
-    def add_page_visit(self, page):
+    def add_page_visit(self, page, path=None):
         visit_count = self.request.session.setdefault('visit_count', [])
         page_visits = [visit for visit in visit_count if visit['id'] == page.pk]
 
@@ -181,6 +181,6 @@ def add_page_visit(self, page):
             visit_count.append({
                 'slug': page.slug,
                 'id': page.pk,
-                'path': self.request.path,
+                'path': path or self.request.path,
                 'count': 1,
             })

src/wagtail_personalisation/views.py

@@ -1,7 +1,9 @@
 from __future__ import absolute_import, unicode_literals
 
-from django.http import HttpResponseForbidden, HttpResponseRedirect
+from django.http import HttpResponseForbidden, HttpResponseRedirect, HttpResponseBadRequest, JsonResponse
 from django.shortcuts import get_object_or_404, reverse
+from django.views.decorators.cache import never_cache
+from django.views.decorators.http import require_POST
 from wagtail.contrib.modeladmin.options import ModelAdmin, modeladmin_register
 from wagtail.contrib.modeladmin.views import IndexView
 
@@ -88,3 +90,37 @@ def copy_page_view(request, page_id, segment_id):
         return HttpResponseRedirect(edit_url)
 
     return HttpResponseForbidden()
+
+
+@never_cache
+@require_POST
+def visit_page(request):
+    """Allows a frontend user to submit a page view and retrieve their current
+    segments on a site that is behind a cache or CDN.
+
+    On each page view, the user must POST to this view the page ID and path
+    that they are browsing. It will return a JSON-formatted document containing
+    a list of segments that are currently active for them.
+    """
+    page_id = request.POST.get('page_id')
+    path = request.POST.get('path')
+
+    if page_id is None or path is None:
+        return HttpResponseBadRequest()
+
+    page = Page.objects.filter(id=page_id).only('id', 'slug', 'live').first()
+
+    if page is None or page.live is False:
+        return HttpResponseBadRequest()
+
+    request.segment_adapter.add_page_visit(page, path=path)
+    request.segments_adapter.refresh()
+
+    return JsonResponse {
+        'segments': [
+            {
+                'slug': segment.encoded_name(),
+            }
+            for segment in request.segments_adapter.get_all_segments()
+        ]
+    }