--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.9/site-packages/galaxy/util/zipstream.py	Mon Mar 22 18:12:50 2021 +0000
@@ -0,0 +1,57 @@
+import os
+from urllib.parse import quote
+
+import zipstream
+
+from .path import safe_walk
+
+
+class ZipstreamWrapper:
+
+    def __init__(self, archive_name=None, upstream_mod_zip=False, upstream_gzip=False):
+        self.upstream_mod_zip = upstream_mod_zip
+        self.archive_name = archive_name
+        if not self.upstream_mod_zip:
+            self.archive = zipstream.ZipFile(allowZip64=True, compression=zipstream.ZIP_STORED if upstream_gzip else zipstream.ZIP_DEFLATED)
+        self.files = []
+        self.size = 0
+
+    def response(self):
+        if self.upstream_mod_zip:
+            yield "\n".join(self.files).encode()
+        else:
+            yield iter(self.archive)
+
+    def get_headers(self):
+        headers = {}
+        if self.archive_name:
+            headers['Content-Disposition'] = f'attachment; filename="{self.archive_name}.zip"'
+        if self.upstream_mod_zip:
+            headers['X-Archive-Files'] = 'zip'
+        else:
+            headers['Content-Type'] = 'application/x-zip-compressed'
+        return headers
+
+    def add_path(self, path, archive_name):
+        size = int(os.stat(path).st_size)
+        if self.upstream_mod_zip:
+            # calculating crc32 would defeat the point of using mod-zip, but if we ever calculate hashsums we should consider this
+            crc32 = "-"
+            line = f"{crc32} {size} {quote(path)} {archive_name}"
+            self.files.append(line)
+        else:
+            self.size += size
+            self.archive.write(path, archive_name)
+
+    def write(self, path, archive_name=None):
+        if os.path.isdir(path):
+            pardir = os.path.join(path, os.pardir)
+            for root, directories, files in safe_walk(path):
+                for directory in directories:
+                    dir_path = os.path.join(root, directory)
+                    self.add_path(dir_path, os.path.relpath(dir_path, pardir))
+                for file in files:
+                    file_path = os.path.join(root, file)
+                    self.add_path(file_path, os.path.relpath(file_path, pardir))
+        else:
+            self.add_path(path, archive_name or os.path.basename(path))