nghttpx server push is initiated by looking for Link header field from
backend server response. Currently we only enable server push for
HTTP/1 backend and without HTTP/2 proxy mode. The URIs which have
rel=preload are eligible to resource to be pushed.
Now concatenating header values with 0x00 as delimiter is not
necessary because HPACK reference set is removed and the order of
header field fed into HPACK encoder is preserved when they are
decoded.
nghttp2 library itself now accept octet header/value pairs,
completely not restricted by HTTP/1 header name/value rule.
The applications may impose restriction about them using
validators.
Now, in nghttp2_on_frame_recv_callback, nva and nvlen in
HEADERS and PUSH_PROMISE frames are always NULL and 0 respectively.
The header name/value pairs are emitted successive
nghttp2_on_header_callback functions. The end of header fields are
signaled with nghttp2_on_end_headers_callback function.
Since NGHTTP2_ERR_PAUSE for nghttp2_on_frame_recv_callback is
introduced to handle header block, it is now deprecated.
Instead, nghttp2_on_header_callback can be paused using
NGHTTP2_ERR_PAUSE.
We thought that this kind of rewrite can be achieved by the configuration
of the backend severs, but in some configuration, however, it may get
complicated. So we decided to implement at least location rewrite in
nghttpx.
This commit also contains a fix to the bug which prevents the http2
backend request from concatenating header fields with the same value.
Remove sorting headers from library code. The application must sort
them if necessary. nghttpx and nghttpd do the sorting of the headers
in stable way if names are equal.
Tatsuhiro Tsujikawa