On 02/01/2025 06:52, Nicolas Frattaroli wrote:
In some cases, webservers may return content more quickly if one sends many small requests rather than one big request. Clients may wish to opt-in to this workaround.For this purpose, add a max_request_size AVOption, which returns EOF if max_request_size is exceeded, causing a new request with an offset to be issued. In particular, this hack is useful for mpv, where it can be used to bypass YouTube's throttling. Signed-off-by: Nicolas Frattaroli <ffm...@fratti.ch> --- Changes in v2: - Fix the request hanging if s->filesize < max_request_size --- libavformat/http.c | 43 +++++++++++++++++++++++++++++++------------ 1 file changed, 31 insertions(+), 12 deletions(-) diff --git a/libavformat/http.c b/libavformat/http.c index ec60bc0b17..977cc8df7e 100644 --- a/libavformat/http.c +++ b/libavformat/http.c @@ -75,7 +75,7 @@ typedef struct HTTPContext { /* Used if "Transfer-Encoding: chunked" otherwise -1. */ uint64_t chunksize; int chunkend; - uint64_t off, end_off, filesize; + uint64_t off, end_off, filesize, max_request_size, range_end; char *uri; char *location; HTTPAuthState auth_state; @@ -174,6 +174,7 @@ static const AVOption options[] = { { "location", "The actual location of the data received", OFFSET(location), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E }, { "offset", "initial byte offset", OFFSET(off), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, D }, { "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 }, + { "max_request_size", "try to limit the request to this many bytes, then reconnect", OFFSET(max_request_size), 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_BOOL, { .i64 = 0 }, 0, 1, D }, { "reconnect_at_eof", "auto reconnect at EOF", OFFSET(reconnect_at_eof), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D }, @@ -1522,10 +1523,16 @@ static int http_connect(URLContext *h, const char *path, const char *local_path, // Note: we send the Range header on purpose, even when we're probing, // since it allows us to detect more reliably if a (non-conforming) // server supports seeking by analysing the reply headers. - if (!has_header(s->headers, "\r\nRange: ") && !post && (s->off > 0 || s->end_off || s->seekable != 0)) { + if (!has_header(s->headers, "\r\nRange: ") && !post && (s->off > 0 || s->end_off || s->seekable != 0 || s->max_request_size)) { av_bprintf(&request, "Range: bytes=%"PRIu64"-", s->off); - if (s->end_off) - av_bprintf(&request, "%"PRId64, s->end_off - 1); + if (s->end_off || s->max_request_size) { + if (s->end_off && s->max_request_size) { + s->range_end = FFMIN(s->end_off, s->off + s->max_request_size); + } else { + s->range_end = FFMAX(s->end_off, s->off + s->max_request_size); + } + av_bprintf(&request, "%"PRId64, s->range_end - 1); + } av_bprintf(&request, "\r\n"); } if (send_expect_100 && !has_header(s->headers, "\r\nExpect: ")) @@ -1664,7 +1671,16 @@ static int http_buf_read(URLContext *h, uint8_t *buf, int size) memcpy(buf, s->buf_ptr, len); s->buf_ptr += len; } else { - uint64_t target_end = s->end_off ? s->end_off : s->filesize; + uint64_t target_end = s->filesize; + if (s->end_off || s->max_request_size) { + if (s->end_off && s->max_request_size) { + target_end = FFMIN(s->end_off, s->range_end); + } else { + target_end = FFMAX(s->end_off, s->range_end); + } + target_end = FFMIN(target_end, s->filesize); + } + if ((!s->willclose || s->chunksize == UINT64_MAX) && s->off >= target_end) return AVERROR_EOF; len = ffurl_read(s->hd, buf, size); @@ -1762,13 +1778,16 @@ static int http_read_stream(URLContext *h, uint8_t *buf, int size) reconnect_delay_total > s->reconnect_delay_total_max) return AVERROR(EIO);- av_log(h, AV_LOG_WARNING, "Will reconnect at %"PRIu64" in %d second(s), error=%s.\n", s->off, reconnect_delay, av_err2str(read_ret));- err = ff_network_sleep_interruptible(1000U*1000*reconnect_delay, &h->interrupt_callback); - if (err != AVERROR(ETIMEDOUT)) - return err; - reconnect_delay_total += reconnect_delay; - reconnect_delay = 1 + 2*reconnect_delay; - conn_attempts++; + if (!(s->max_request_size > 0 && read_ret == AVERROR_EOF)) { + av_log(h, AV_LOG_WARNING, "Will reconnect at %"PRIu64" in %d second(s), error=%s.\n", + s->off, reconnect_delay, av_err2str(read_ret)); + err = ff_network_sleep_interruptible(1000U*1000*reconnect_delay, &h->interrupt_callback); + if (err != AVERROR(ETIMEDOUT)) + return err; + reconnect_delay_total += reconnect_delay; + reconnect_delay = 1 + 2*reconnect_delay; + conn_attempts++; + } seek_ret = http_seek_internal(h, target, SEEK_SET, 1); if (seek_ret >= 0 && seek_ret != target) { av_log(h, AV_LOG_ERROR, "Failed to reconnect at %"PRIu64".\n", target);
This can be useful, so LGTM, but someone more familiar with http should comment.
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