#29241: ConditionalGetMiddleware and x-sendfile
-------------------------------------+-------------------------------------
Reporter: TZanke | Owner: nobody
Type: Bug | Status: new
Component: Core (Cache system) | Version: 1.11
Severity: Normal | Resolution:
Keywords: sendfile | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Old description:
> We found a issue with ConditionalGetMiddleware in combination with apache
> x-sendfile (django-sendfile) and Django 1.11
>
> In Django 1.10 we just use Last-Modified, which works fine. Now with
> Django 1.11 each response gets a ETag generated based on
> response.content. In the case of a x-sendfile response, the
> response.content is an empty string. So each time the file is accessed,
> the ETag generated by ConditionalGetMiddleware is the same. Regardless of
> the changed file/changed mtime.
>
> So now the request has our Last-Modified header AND the Middleware
> generated ETag.
> In get_conditional_response the ETag, which is always the same hash of
> empty string, is checked first and returns a 304. BUT the Last-
> Modification has changed and is ignored.
>
> This looks like two bugs for me. First the ETag of the empty content
> string from x-sendfile respose. Second returning a 304 if ETag is the
> same but Last-Mofified has changed.
New description:
We found a issue with ConditionalGetMiddleware in combination with apache
x-sendfile (django-sendfile) and Django 1.11
In Django 1.10 we just use Last-Modified, which works fine. Now with
Django 1.11 each response gets a ETag generated based on response.content.
In the case of a x-sendfile response, the response.content is an empty
string. So each time the file is accessed, the ETag generated by
ConditionalGetMiddleware is the same. Regardless of the changed
file/changed mtime.
So now the request has our Last-Modified header AND the Middleware
generated ETag.
In get_conditional_response the ETag, which is always the same hash of
empty string, is checked first and returns a 304. BUT the Last-
Modification has changed and is ignored.
This looks like two bugs for me. First the ETag of the empty content
string from x-sendfile respose. Second returning a 304 if ETag is the same
but Last-Modified has changed.
--
Comment (by Tim Graham):
If there are two bugs, there should be two tickets. Will you offer some
fixes?
--
Ticket URL: <https://code.djangoproject.com/ticket/29241#comment:1>
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