httpd: Support caching via ETag header

If server responds with ETag then next time client can resend it via If-None-Match header.
Then httpd will check if file wasn't modified and if not return 304 Not Modified status code.
The ETag value is constructed from file's last modification date in unix epoch and it's size:
"hex(last_mod)-hex(file_size)" e.g. "5e132e20-417" (with quotes).
That means that it's not completely reliable as hash functions but fair enough.
The same form of ETag is used by Nginx so load balancing of static content is safe.

function                                             old     new   delta
handle_incoming_and_exit                            2135    2201     +66
http_response                                         88      96      +8
send_headers                                         676     683      +7
parse_conf                                          1362    1365      +3
http_response_type                                    22      24      +2
send_file_and_exit                                   847     841      -6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/1 up/down: 86/-6)              Total: 80 bytes

Signed-off-by: Sergey Ponomarev <stokito@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

0 files changed, 0 insertions, 0 deletions