Initial commit

env/lib/python3.10/site-packages/wagtail/utils/sendfile_streaming_backend.py

@@ -0,0 +1,50 @@
+# Sendfile "streaming" backend
+# This is based on sendfiles builtin "simple" backend but uses a StreamingHttpResponse
+
+import os
+import stat
+from email.utils import mktime_tz, parsedate_tz
+
+from django.http import FileResponse, HttpResponseNotModified
+from django.utils.http import http_date
+
+
+def sendfile(request, filename, **kwargs):
+    # Respect the If-Modified-Since header.
+    statobj = os.stat(filename)
+
+    if not was_modified_since(
+        request.headers.get("if-modified-since"),
+        statobj[stat.ST_MTIME],
+    ):
+        return HttpResponseNotModified()
+
+    response = FileResponse(open(filename, "rb"))
+
+    response["Last-Modified"] = http_date(statobj[stat.ST_MTIME])
+    return response
+
+
+def was_modified_since(header=None, mtime=0):
+    """
+    Was something modified since the user last downloaded it?
+
+    header
+      This is the value of the If-Modified-Since header.  If this is None,
+      I'll just return True.
+
+    mtime
+      This is the modification time of the item we're talking about.
+    """
+    try:
+        if header is None:
+            raise ValueError
+        header_date = parsedate_tz(header)
+        if header_date is None:
+            raise ValueError
+        header_mtime = mktime_tz(header_date)
+        if mtime > header_mtime:
+            raise ValueError
+    except (ValueError, OverflowError):
+        return True
+    return False