[FFmpeg-devel] [PATCH 7/9] lavf/http: increase range for listen, handle connection closing accordingly, add http_handshake and move handshake logic there

[Stephan Holljes]

On Fri, Jul 3, 2015 at 4:18 PM, Nicolas George <george at nsup.org> wrote:
> Le quintidi 15 messidor, an CCXXIII, Stephan Holljes a écrit :
>> Signed-off-by: Stephan Holljes <klaxa1337 at googlemail.com>
>> ---
>>  libavformat/http.c | 45 ++++++++++++++++++++++++++++++++-------------
>>  1 file changed, 32 insertions(+), 13 deletions(-)
>>
>> diff --git a/libavformat/http.c b/libavformat/http.c
>> index d9c3624..95065f5 100644
>> --- a/libavformat/http.c
>> +++ b/libavformat/http.c
>> @@ -129,7 +129,7 @@ static const AVOption options[] = {
>>      { "end_offset", "try to limit the request to bytes preceding this offset", OFFSET(end_off), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, D },
>>      { "method", "Override the HTTP method or set the expected HTTP method from a client", OFFSET(method), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
>>      { "reconnect", "auto reconnect after disconnect before EOF", OFFSET(reconnect), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, D },
>> -    { "listen", "listen on HTTP", OFFSET(listen), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, D | E },
>> +    { "listen", "listen on HTTP", OFFSET(listen), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 2, D | E },
>>      { NULL }
>>  };
>>
>> @@ -307,6 +307,8 @@ static void handle_http_errors(URLContext *h, int error)
>>      HTTPContext *s = h->priv_data;
>>      if (h->is_connected) {
>>          switch(error) {
>> +            case 0:
>> +                break;
>>              case AVERROR_HTTP_BAD_REQUEST:
>>                  ffurl_write(s->hd, bad_request, strlen(bad_request));
>>                  break;
>> @@ -317,15 +319,32 @@ static void handle_http_errors(URLContext *h, int error)
>>      }
>>  }
>>
>> +static int http_handshake(URLContext *c) {
>> +    int ret, err = 0, new_location;
>> +    HTTPContext *ch = c->priv_data;
>> +    URLContext *cl = ch->hd;
>> +    static const char header[] = "HTTP/1.1 200 OK\r\nContent-Type: application/octet-stream\r\nTransfer-Encoding: chunked\r\n\r\n";
>> +    if ((ret = ffurl_handshake(cl)) < 0)
>> +        return ret;
>> +    if ((err = http_read_header(c, &new_location)) < 0)
>> +        goto fail;
>> +    if ((ret = ffurl_write(cl, header, strlen(header))) < 0)
>> +        goto fail;
>
>> +    // Avoid returning a positive value from ffurl_write()
>> +    ret = ret > 0 ? 0 : ret;
>> +fail:
>> +    handle_http_errors(c, err);
>> +    return ret;
>
> This is a matter of taste, but I find it more readable if it avoids going
> over the "fail" label:
>
> +    if ((ret = ffurl_write(cl, header, strlen(header))) < 0)
> +        goto fail;
> +    return 0;
> +fail:
> +    handle_http_errors(c, err);
> +    return ret;
>
> That way, you also do not need to change handle_http_errors() for error=0.
> (Although av_assert0(error < 0) would do no harm there.)
>
>> +}
>> +
>>  static int http_listen(URLContext *h, const char *uri, int flags,
>>                         AVDictionary **options) {
>>      HTTPContext *s = h->priv_data;
>>      int ret;
>> -    static const char header[] = "HTTP/1.1 200 OK\r\nContent-Type: application/octet-stream\r\nTransfer-Encoding: chunked\r\n\r\n";
>>      char hostname[1024], proto[10];
>>      char lower_url[100];
>>      const char *lower_proto = "tcp";
>> -    int port, new_location;
>> +    int port;
>>      s->chunked_post = 1;
>>      av_url_split(proto, sizeof(proto), NULL, 0, hostname, sizeof(hostname), &port,
>>                   NULL, 0, uri);
>> @@ -333,18 +352,16 @@ static int http_listen(URLContext *h, const char *uri, int flags,
>>          lower_proto = "tls";
>>      ff_url_join(lower_url, sizeof(lower_url), lower_proto, NULL, hostname, port,
>>                  NULL);
>> -    av_dict_set(options, "listen", "1", 0);
>> +    if ((ret = av_dict_set_int(options, "listen", s->listen, 0)) < 0)
>> +        goto fail;
>>      if ((ret = ffurl_open(&s->hd, lower_url, AVIO_FLAG_READ_WRITE,
>>                            &h->interrupt_callback, options)) < 0)
>>          goto fail;
>> -    if ((ret = http_read_header(h, &new_location)) < 0)
>> -         goto fail;
>> -    if ((ret = ffurl_write(s->hd, header, strlen(header))) < 0)
>> -         goto fail;
>> -    return 0;
>> -
>> +    if (s->listen == 1) {
>> +        // single client
>> +        ret = http_handshake(h);
>> +    }
>>  fail:
>> -    handle_http_errors(h, ret);
>>      av_dict_free(&s->chained_options);
>>      return ret;
>>  }
>> @@ -1263,7 +1280,7 @@ static int http_shutdown(URLContext *h, int flags)
>>
>
>>      /* signal end of chunked encoding if used */
>>      if (((flags & AVIO_FLAG_WRITE) && s->chunked_post) ||
>> -        ((flags & AVIO_FLAG_READ) && s->chunked_post && s->listen)) {
>> +        ((flags & AVIO_FLAG_READ) && s->chunked_post && s->listen == 1)) {
>>          ret = ffurl_write(s->hd, footer, sizeof(footer) - 1);
>>          ret = ret > 0 ? 0 : ret;
>>          s->end_chunked_post = 1;
>> @@ -1282,7 +1299,7 @@ static int http_close(URLContext *h)
>>      av_freep(&s->inflate_buffer);
>>  #endif /* CONFIG_ZLIB */
>>
>> -    if (!s->end_chunked_post)
>> +    if ((s->listen != 2 && !s->end_chunked_post))
>
> The two tests on s->listen seem redundant. Maybe it would be better to take
> the time of renaming a few fields in the structure to make the underlying
> logic simpler.

Those tests made sense (and I think were even necessary?) when I wrote
them. I removed them and tested both, multi-client and one-shot
server, and they appear to be closing the connections correctly.

>
> Also, the parentheses in that last line are strange.
>
>>          /* Close the write direction by sending the end of chunked encoding. */
>>          ret = http_shutdown(h, h->flags);
>>
>> @@ -1365,6 +1382,8 @@ HTTP_CLASS(http);
>>  URLProtocol ff_http_protocol = {
>>      .name                = "http",
>>      .url_open2           = http_open,
>> +    .url_accept          = http_accept,
>> +    .url_handshake       = http_handshake,
>>      .url_read            = http_read,
>>      .url_write           = http_write,
>>      .url_seek            = http_seek,
>
> Regards,
>
> --
>   Nicolas George

Regards,
Stephan