From e6d68c73b82a06ff1fdda7d3d4819b194311e1db Mon Sep 17 00:00:00 2001
From: Tanner Prestegard <tanner.prestegard@ligo.org>
Date: Thu, 12 Jul 2018 12:44:51 -0500
Subject: [PATCH] adding utilities for serving files
---
gracedb/core/http.py | 63 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 63 insertions(+)
create mode 100644 gracedb/core/http.py
diff --git a/gracedb/core/http.py b/gracedb/core/http.py
new file mode 100644
index 000000000..2285139ef
--- /dev/null
+++ b/gracedb/core/http.py
@@ -0,0 +1,63 @@
+# Request/response utilities
+from django.http import HttpResponse
+
+from .vfile import VersionedFile
+
+import os
+
+
+def serve_file(file_path, ResponseClass=HttpResponse):
+ """
+ Take an absolute path to a file and construct a response.
+ Files are served by Apache through X-Sendfile.
+
+ If a certain response class is desired, it can be passed as an argument.
+ Typically will be django.http.HttpResponse or
+ rest_framework.response.Response.
+
+ This function does NOT check that the file exists and is readable,
+ or whether the user should be allowed to download the file.
+ """
+
+ # Try to guess file content type; if unknown, set as octet-stream
+ content_type, encoding = VersionedFile.guess_mimetype(file_path)
+ content_type = content_type or "application/octet-stream"
+
+ # Set up response object
+ response = ResponseClass()
+
+ # Configure response to have Apache serve the file with X-Sendfile
+ response['X-Sendfile'] = file_path
+
+ # For binary files, add the file as an attachment (direct download instead
+ # of opening in browser window)
+ if content_type == "application/octet-stream":
+ response['Content-Disposition'] = 'attachment; filename="{0}"'.format(
+ os.path.basename(file_path))
+
+ return response
+
+
+def check_and_serve_file(request, file_path, ResponseClass=HttpResponse):
+ """
+ Checks whether a file exists and is readable. If so, the file is served.
+ Does not check permissions - that should be done before this function
+ is called.
+
+ This function returns a response, so it should be called within a view,
+ not from within a view subfunction or method.
+ """
+
+ if not os.path.exists(file_path):
+ err_msg = "File {0} not found".format(os.path.basename(file_path))
+ # File not found - return 404 NOT FOUND response
+ response = ResponseClass(err_msg, status=404)
+ elif not os.access(file_path, os.R_OK):
+ err_msg = "File {0} is not readable".format(
+ os.path.basename(file_path))
+ # File not readable - return 500 SERVER ERROR response
+ response = ResponseClass(err_msg, status=500)
+ elif os.path.isfile(file_path):
+ response = serve_file(file_path, ResponseClass)
+
+ return response
--
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