Hook up preview (#1580)

* fetch draft pages if query param is passed

* hook up preview in admin for flexpages

* 👕

openstax/api.py

@@ -1,14 +1,16 @@
 from django.core.exceptions import MultipleObjectsReturned
 from django.shortcuts import redirect
 from django.urls import reverse, path
+from django.conf import settings
 
+from rest_framework.response import Response
+
+from wagtail.models import Page, PageViewRestriction, Site
 from wagtail.api.v2.router import WagtailAPIRouter
 from wagtail.api.v2.views import PagesAPIViewSet, BaseAPIViewSet
 from wagtail.images.api.v2.views import ImagesAPIViewSet
 from wagtail.documents.api.v2.views import DocumentsAPIViewSet
 
-
-
 class OpenstaxPagesAPIEndpoint(PagesAPIViewSet):
     """
     OpenStax custom Pages API endpoint that allows finding pages and books by pk or slug
@@ -20,7 +22,13 @@ def detail_view(self, request, pk=None, slug=None):
             self.lookup_field = 'slug'
             param = slug
         try:
-            return super().detail_view(request, param)
+            instance = self.get_object()
+
+            if request.GET.get('draft'):
+                instance = instance.get_latest_revision_as_object()
+
+            serializer = self.get_serializer(instance)
+            return Response(serializer.data)
         except MultipleObjectsReturned:
             # Redirect to the listing view, filtered by the relevant slug
             # The router is registered with the `wagtailapi` namespace,
@@ -41,6 +49,75 @@ def get_urlpatterns(cls):
             path('find/', cls.as_view({'get': 'find_view'}), name='find'),
         ]
 
+    def get_base_queryset(self):
+        """
+        this method copied from https://github.com/wagtail/wagtail/blob/main/wagtail/api/v2/views.py#L491
+        so that we can change the line that says:
+             queryset = Page.objects.all().live()
+        to:
+             queryset = Page.objects.all()
+
+        when viewing draft content is enabled
+        """
+
+        request = self.request
+
+        if request.GET.get('draft'):
+            # Get all pages including drafts
+            queryset = Page.objects.all()
+        else:
+            # Get all live pages
+            queryset = Page.objects.all().live()
+
+        # Exclude pages that the user doesn't have access to
+        restricted_pages = [
+            restriction.page
+            for restriction in PageViewRestriction.objects.all().select_related("page")
+            if not restriction.accept_request(self.request)
+        ]
+
+        # Exclude the restricted pages and their descendants from the queryset
+        for restricted_page in restricted_pages:
+            queryset = queryset.not_descendant_of(restricted_page, inclusive=True)
+
+        # Check if we have a specific site to look for
+        if "site" in request.GET:
+            # Optionally allow querying by port
+            if ":" in request.GET["site"]:
+                (hostname, port) = request.GET["site"].split(":", 1)
+                query = {
+                    "hostname": hostname,
+                    "port": port,
+                }
+            else:
+                query = {
+                    "hostname": request.GET["site"],
+                }
+            try:
+                site = Site.objects.get(**query)
+            except Site.MultipleObjectsReturned:
+                raise BadRequestError(
+                    "Your query returned multiple sites. Try adding a port number to your site filter."
+                )
+        else:
+            # Otherwise, find the site from the request
+            site = Site.find_for_request(self.request)
+
+        if site:
+            base_queryset = queryset
+            queryset = base_queryset.descendant_of(site.root_page, inclusive=True)
+
+            # If internationalisation is enabled, include pages from other language trees
+            if getattr(settings, "WAGTAIL_I18N_ENABLED", False):
+                for translation in site.root_page.get_translations():
+                    queryset |= base_queryset.descendant_of(translation, inclusive=True)
+
+        else:
+            # No sites configured
+            queryset = queryset.none()
+
+        return queryset
+
 
 class OpenStaxImagesAPIViewSet(ImagesAPIViewSet):
     meta_fields = BaseAPIViewSet.meta_fields + ['tags', 'download_url', 'height', 'width']

pages/models.py

@@ -1,5 +1,6 @@
 from django import forms
 from django.db import models
+from django.shortcuts import render
 
 from modelcluster.fields import ParentalKey
 from wagtail.admin.panels import FieldPanel, InlinePanel, MultiFieldPanel, TitleFieldPanel
@@ -205,7 +206,6 @@ class RootPage(Page):
     ]
 
     template = 'page.html'
-    preview_modes = []
     max_count = 1
     # TODO: we are allowing this to be built as a child of the homepage. Not ideal.
     # Once the home page is released, use something to migrate homepage children to root page and remove this parent type.
@@ -223,8 +223,19 @@ def get_url_parts(self, *args, **kwargs):
 
         # note that we ignore the slug and hardcode this url to / for the root page
         site_id, site_root_url, page_url_relative_to_site_root = url_parts
+
         return (site_id, site_root_url, '/')
 
+    def serve_preview(self, request, mode_name):
+        site_id, site_root, relative_page_url = self.get_url_parts(request)
+        preview_url = '{}{}/?preview={}'.format(site_root, relative_page_url, mode_name)
+
+        return render(
+            request,
+            "preview.html",
+            {"preview_url": preview_url},
+        )
+
 # subclass of RootPage with a few overrides for subpages
 class FlexPage(RootPage):
     parent_page_types = ['pages.RootPage', 'pages.FlexPage']

pages/templates/preview.html

@@ -0,0 +1,6 @@
+<style>
+    body, html {
+        margin: 0; padding: 0; height: 100%; overflow: hidden;
+    }
+</style>
+<iframe src="{{ preview_url }}" width="100%" height="100%" style="border: none;"></iframe>