HLS-Retry mechanism for HTTP-Upload segments

[Martini]

Summary of the enhancement:
Retry hls-segment upload once, if web server returns HTTP 500.
How to reproduce:

% ffmpeg -i http://wdr-1live-live.cast.addradio.de/wdr/1live/live/mp3/128/stream.mp3 -ar 48000 -c:a libfdk_aac -b:a 128k -f hls -hls_time 2 -method PUT -hls_segment_filename 'http://18.185.31.81/%v/segment_%04d.ts' -master_pl_name 'master.m3u8' -timeout 2 'http://18.185.31.81/%v/out.m3u8' -loglevel trace
ffmpeg version n4.0.1
built on ubuntu 16.04

1.
​https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/hlsenc.c#L277
First I thought I can just rerun „ff_http_do_new_request“ if result shows failed state
But function does NOT return any errors, if webserver returns HTTP 500.

2.
„ff_http_do_new_request“ refers to -> „http_open_cnx“
​https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/http.c#L283
I thought that I can extend handling for http_code 30x for http_code 500, but function „http_open_cnx_internal“ did never return this code, though web server did (see 1.)

3.
„http_open_cnx“ refers to -> „http_open_cnx_internal“ refers to -> „http_connect“.
​https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/http.c#L1311

Here this function returns ALWAYS http_code 200 for posting data.

Function „http_read_header“ will NEVER be executed.
​https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/http.c#L1317

[smallishzulu]

This problem happens only for the cases like:

1) Server is there and accpets the connection (handshake)
2) However, server does hve the patch to PUT the data.

On; http.c at http_connect, before ffurl_write functions, there needs to have a block to check if URL is valid.

A simple bash check:

curl -w '%{http_code}' --request PUT --url "​http://176.235.14.189:9090/OTTCAHLS"/  --data
curl: (52) Empty reply from server
000

curl -w '%{http_code}' --request PUT --url "​http://176.235.14.189:9090/OTTCAHLS200/"  --data
500

(bash is just an example, a c code need to be written. I work on it.)

If path is not there, HTTP server returns Interal Server Error and curl reports the same.

I couldn't find a better way to handle this becuase, ffurl_write goes to avio.c and you cant access HTTPContext from there.