add `--cert-url` to end server too

Cargo.lock

@@ -1332,6 +1332,7 @@ dependencies = [
  "hyper",
  "quinn",
  "rcgen",
+ "reqwest",
  "rmp-serde",
  "structopt",
  "tokio",

prototypes/quic_demo/Cargo.toml

@@ -15,6 +15,7 @@ futures-util = "0.3.9"
 hyper = { version = "0.14.4", features = ["http1", "server", "stream", "tcp"] }
 quinn = "0.7.2"
 rcgen = "0.8.11"
+reqwest = "0.11.4"
 rmp-serde = "0.15.5"
 structopt = "0.3.20"
 tokio = { version = "1.8.1", features = ["full"] }

prototypes/quic_demo/src/bin/quic_demo_end_server.rs

@@ -12,6 +12,8 @@ struct Opt {
 	server_id: Option <PeerId>,
 	#[structopt (long)]
 	debug_echo: bool,
+	#[structopt (long)]
+	cert_url: Option <String>,
 }
 
 #[tokio::main]
@@ -20,7 +22,10 @@ async fn main () -> anyhow::Result <()> {
 	
 	let opt = Arc::new (Opt::from_args ());
 	
-	let server_cert = tokio::fs::read ("quic_server.crt").await?;
+	let server_cert = match opt.cert_url.as_ref () {
+		Some (url) => reqwest::get (url).await?.bytes ().await?,
+		None => tokio::fs::read ("quic_server.crt").await?.into (),
+	};
 	let relay_addr = opt.relay_addr.clone ().unwrap_or_else (|| String::from ("127.0.0.1:30380")).parse ()?;
 	let endpoint = make_client_endpoint ("0.0.0.0:0".parse ()?, &[&server_cert])?;