API support for downloading compressed archives of multiple documents

src/documents/bulk_download.py

@@ -0,0 +1,60 @@
+from zipfile import ZipFile
+
+from documents.models import Document
+
+
+class BulkArchiveStrategy:
+
+    def __init__(self, zipf: ZipFile):
+        self.zipf = zipf
+
+    def make_unique_filename(self,
+                             doc: Document,
+                             archive: bool = False,
+                             folder: str = ""):
+        counter = 0
+        while True:
+            filename = folder + doc.get_public_filename(archive, counter)
+            if filename in self.zipf.namelist():
+                counter += 1
+            else:
+                return filename
+
+    def add_document(self, doc: Document):
+        raise NotImplementedError()  # pragma: no cover
+
+
+class OriginalsOnlyStrategy(BulkArchiveStrategy):
+
+    def add_document(self, doc: Document):
+        self.zipf.write(doc.source_path, self.make_unique_filename(doc))
+
+
+class ArchiveOnlyStrategy(BulkArchiveStrategy):
+
+    def __init__(self, zipf):
+        super(ArchiveOnlyStrategy, self).__init__(zipf)
+
+    def add_document(self, doc: Document):
+        if doc.has_archive_version:
+            self.zipf.write(doc.archive_path,
+                            self.make_unique_filename(doc, archive=True))
+        else:
+            self.zipf.write(doc.source_path,
+                            self.make_unique_filename(doc))
+
+
+class OriginalAndArchiveStrategy(BulkArchiveStrategy):
+
+    def add_document(self, doc: Document):
+        if doc.has_archive_version:
+            self.zipf.write(
+                doc.archive_path, self.make_unique_filename(
+                    doc, archive=True, folder="archive/"
+                )
+            )
+
+        self.zipf.write(
+            doc.source_path,
+            self.make_unique_filename(doc, folder="originals/")
+        )