moq-rtc 0.1.2

WebRTC (WHIP/WHEP) gateway for Media over QUIC
Documentation 
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//! `client publish`: dial a remote WHIP endpoint and push a MoQ broadcast
//! out as RTP.
//!
//! Mints an SDP offer with `sendonly` audio + video, POSTs it to the WHIP
//! resource URL, parses the returned answer, and hands the resulting
//! `str0m::Rtc` to a `crate::session::Session` running in egress mode. The
//! bitstream / RTP packetization is identical to the WHEP server path, so
//! most of the work lives in [`crate::egress`].

use str0m::{
	Candidate,
	change::SdpAnswer,
	media::{Direction, MediaKind},
};
use url::Url;

use crate::{Error, Result, client::Client, egress::EgressSource, session};

pub(crate) async fn dial(client: &Client, url: Url, broadcast: moq_net::BroadcastConsumer) -> Result<()> {
	let source = EgressSource::new(broadcast).await?;
	let codecs = source.catalog_codecs();
	if codecs.is_empty() {
		return Err(Error::Other(anyhow::anyhow!(
			"catalog has no codecs we can egress (Opus / H.264 / H.265 / VP8 / VP9 / AV1)"
		)));
	}

	let (socket, candidates) = session::bind_udp(&client.config().ice_candidates).await?;
	// Restrict to codecs the catalog can actually source so the remote
	// answer doesn't pick a codec we have no rendition for.
	let mut rtc = session::rtc_with_codecs(&codecs);
	for addr in &candidates {
		let cand = Candidate::host(*addr, "udp").map_err(str0m::RtcError::from)?;
		rtc.add_local_candidate(cand);
	}

	// Advertise sendonly audio + video; `rtc_with_codecs` already pinned
	// the offer's codec list to what the catalog can source.
	let mut api = rtc.sdp_api();
	api.add_media(MediaKind::Audio, Direction::SendOnly, None, None, None);
	api.add_media(MediaKind::Video, Direction::SendOnly, None, None, None);
	let (offer, pending) = api
		.apply()
		.ok_or_else(|| Error::Other(anyhow::anyhow!("no SDP changes to apply")))?;

	let res = client
		.http()
		.post(url.clone())
		.header(reqwest::header::CONTENT_TYPE, "application/sdp")
		.header(reqwest::header::ACCEPT, "application/sdp")
		.body(offer.to_sdp_string())
		.send()
		.await
		.map_err(|err| Error::Other(anyhow::anyhow!("WHIP POST failed: {err}")))?;

	if !res.status().is_success() {
		return Err(Error::Other(anyhow::anyhow!("WHIP server returned {}", res.status())));
	}

	let body = res
		.text()
		.await
		.map_err(|err| Error::Other(anyhow::anyhow!("reading WHIP answer body: {err}")))?;
	let answer = SdpAnswer::from_sdp_string(&body).map_err(|err| Error::InvalidSdp(err.to_string()))?;

	rtc.sdp_api().accept_answer(pending, answer).map_err(Error::Rtc)?;
	tracing::info!(%url, "whip client connected");

	// 1:1 socket (no demux on the client): pump its datagrams into the session.
	// The session tags each datagram with the advertised candidate matching its
	// family (str0m matches the destination against a host candidate, not the bind).
	let inbound = session::spawn_socket_reader(socket.clone());
	let session = session::Session::egress(rtc, socket, candidates, inbound, source);
	tokio::spawn(async move {
		let result = session.run().await;
		session::log_session_end("whip client", &result);
	});

	Ok(())
}