Merge pull request #2713 from WesleyAC/buffer-csv-export

Change CSV export to buffer instead of streaming

bookwyrm/tests/views/preferences/test_export.py

@@ -1,7 +1,7 @@
 """ test for app action functionality """
 from unittest.mock import patch
 
-from django.http import StreamingHttpResponse
+from django.http import HttpResponse
 from django.test import TestCase
 from django.test.client import RequestFactory
 
@@ -57,13 +57,12 @@ class ExportViews(TestCase):
         request = self.factory.post("")
         request.user = self.local_user
         export = views.Export.as_view()(request)
-        self.assertIsInstance(export, StreamingHttpResponse)
+        self.assertIsInstance(export, HttpResponse)
         self.assertEqual(export.status_code, 200)
-        result = list(export.streaming_content)
         # pylint: disable=line-too-long
         self.assertEqual(
-            result[0],
-            b"title,author_text,remote_id,openlibrary_key,inventaire_id,librarything_key,goodreads_key,bnf_id,viaf,wikidata,asin,aasin,isfdb,isbn_10,isbn_13,oclc_number,rating,review_name,review_cw,review_content\r\n",
+            export.content,
+            b"title,author_text,remote_id,openlibrary_key,inventaire_id,librarything_key,goodreads_key,bnf_id,viaf,wikidata,asin,aasin,isfdb,isbn_10,isbn_13,oclc_number,rating,review_name,review_cw,review_content\r\nTest Book,,"
+            + self.book.remote_id.encode("utf-8")
+            + b",,,,,beep,,,,,,123456789X,9781234567890,,,,,\r\n",
         )
-        expected = f"Test Book,,{self.book.remote_id},,,,,beep,,,,,,123456789X,9781234567890,,,,,\r\n"
-        self.assertEqual(result[1].decode("utf-8"), expected)

bookwyrm/views/preferences/export.py

@@ -1,9 +1,10 @@
 """ Let users export their book data """
 import csv
+import io
 
 from django.contrib.auth.decorators import login_required
 from django.db.models import Q
-from django.http import StreamingHttpResponse
+from django.http import HttpResponse
 from django.template.response import TemplateResponse
 from django.views import View
 from django.utils.decorators import method_decorator
@@ -20,8 +21,8 @@ class Export(View):
         return TemplateResponse(request, "preferences/export.html")
 
     def post(self, request):
-        """Streaming the csv file of a user's book data"""
-        data = (
+        """Download the csv file of a user's book data"""
+        books = (
             models.Edition.viewer_aware_objects(request.user)
             .filter(
                 Q(shelves__user=request.user)
@@ -33,24 +34,9 @@ class Export(View):
             .distinct()
         )
 
-        generator = csv_row_generator(data, request.user)
+        csv_string = io.StringIO()
+        writer = csv.writer(csv_string)
 
-        pseudo_buffer = Echo()
-        writer = csv.writer(pseudo_buffer)
-        # for testing, if you want to see the results in the browser:
-        # from django.http import JsonResponse
-        # return JsonResponse(list(generator), safe=False)
-        return StreamingHttpResponse(
-            (writer.writerow(row) for row in generator),
-            content_type="text/csv",
-            headers={
-                "Content-Disposition": 'attachment; filename="bookwyrm-export.csv"'
-            },
-        )
-
-
-def csv_row_generator(books, user):
-    """generate a csv entry for the user's book"""
         deduplication_fields = [
             f.name
             for f in models.Edition._meta.get_fields()  # pylint: disable=protected-access
@@ -61,11 +47,14 @@ def csv_row_generator(books, user):
             + deduplication_fields
             + ["rating", "review_name", "review_cw", "review_content"]
         )
-    yield fields
+        writer.writerow(fields)
+
         for book in books:
             # I think this is more efficient than doing a subquery in the view? but idk
             review_rating = (
-            models.Review.objects.filter(user=user, book=book, rating__isnull=False)
+                models.Review.objects.filter(
+                    user=request.user, book=book, rating__isnull=False
+                )
                 .order_by("-published_date")
                 .first()
             )
@@ -73,7 +62,9 @@ def csv_row_generator(books, user):
             book.rating = review_rating.rating if review_rating else None
 
             review = (
-            models.Review.objects.filter(user=user, book=book, content__isnull=False)
+                models.Review.objects.filter(
+                    user=request.user, book=book, content__isnull=False
+                )
                 .order_by("-published_date")
                 .first()
             )
@@ -81,15 +72,12 @@ def csv_row_generator(books, user):
                 book.review_name = review.name
                 book.review_cw = review.content_warning
                 book.review_content = review.raw_content
-        yield [getattr(book, field, "") or "" for field in fields]
+            writer.writerow([getattr(book, field, "") or "" for field in fields])
 
-
-class Echo:
-    """An object that implements just the write method of the file-like
-    interface. (https://docs.djangoproject.com/en/3.2/howto/outputting-csv/)
-    """
-
-    # pylint: disable=no-self-use
-    def write(self, value):
-        """Write the value by returning it, instead of storing in a buffer."""
-        return value
+        return HttpResponse(
+            csv_string.getvalue(),
+            content_type="text/csv",
+            headers={
+                "Content-Disposition": 'attachment; filename="bookwyrm-export.csv"'
+            },
+        )