55e47c630b
It turns out that eventlet has been injecting a ``Transfer-Encoding`` header as of recent into WSGI application response headers. The result of this ultimately depends on how the HTTP client which is passing the request to the server is written to handle data. Apache, for example, will return that an invalid response was received. In part because it sees the request end, with an HTTP 204 response code, but also an encoding indicating there is a multipart body encoding inbound. Which is confusing. Other C based HTTP clients can have any number of reactions up to and including disconnecting sessions. Curl, depending on the headers present either returns success but notes body weirdness or actually returns return code 18. Python-Requests kind of has it a little worse, and we see this with clients. With it, it tries to prepare a respones content body based upon the presence of the header indicating there is a body. But it blows up thinking there is more data to read on the socket when there is not more data to read. Regardless, all of this is an RFC7230 violation. Neither Content-Length nor Transfer-Encoding should be on an HTTP 204 response. However, Content-Length is the lesser evil, and we have a similar endpoing in Ironic which *does* explicitly get returned with a zero length content-length, and does not demonstrate such issues. As such, in the interest of the lesser evils until Eventlet's evil ways of header injection are remedied, we're explicitly going to force a Content-Length header to be sent indicating a zero length response. For more information, please see: https://github.com/eventlet/eventlet/issues/746 Change-Id: I014cc65c79222f4d4d7c2b6ff11a76e56659340c
20 lines
1003 B
YAML
20 lines
1003 B
YAML
---
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issues:
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The response headers for empty body HTTP 204 replies, at present, violate
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RFC7230. This was not intentional, but underlying libraries also
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make inappropriate changes to the headers, which can cause clients to
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experience odd failures. This is anticipated to be corrected once an
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underlying issue in
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`eventlet <https://github.com/eventlet/eventlet/issues/746>`_ is resolved.
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fixes:
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Fixes HTTP responses so the Eventlet library, which is used to support
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the operation of the WSGI application, does not incorrectly inject
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a ``Transfer-Encoding`` header into the HTTP response, even on HTTP 204
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replies, which is a violation of RFC7230. This header ultimately can
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cause varying client reactions which are not expected and can raise
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exceptions. For now, this has been remedied via an explicit return of
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a ``Content-Length`` header, which is also an RFC7230 violation, but
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it appears to be the lesser of known evils at this time.
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