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//! The transport seam: com.fedfork.exec.<name>.* pseudo-calls, request and subscribe,
//! served by crates outside atlibs-host (the atlibs-iroh repo). A host registers the transports it was
//! built with, each saying which NSIDs it provides (provides(), for load-time checks); this crate knows
//! none of them. HostCall refuses a connect no transport took: unavailable().
//! javascript/src/run-module/host-call.js is the same seam (its `calls` map) with the same refusal text.
//! A transport may also fetch URLs of its own schemes (webrtc:, iroh:) for com.fedfork.exec.http.fetch:
//! its call's Call::schemes() and Call::fetch(), gathered by fetchers() into run::Http::schemes (JS: runModule's
//! `fetchers`, a transport plugin's fetchers()).
use std::collections::{HashMap, HashSet};
use std::sync::Arc;
use serde_json::{Value, json};
use crate::BoxFut;
use crate::host::{Fetch, Response};
use crate::run::{Call, Request, Sub};
pub const PSEUDO: &str = "com.fedfork.exec.";
/// A transport: the NSIDs it provides (request and subscribe) and the call that serves them.
#[derive(Clone)]
pub struct Transport {
pub provides: &'static [&'static str],
pub call: Arc<dyn Call>,
}
impl Transport {
/// The URL schemes (no colon) whose com.fedfork.exec.http.fetch requests it serves: its call's.
pub fn schemes(&self) -> &'static [&'static str] {
self.call.schemes()
}
}
/// One request to a URL of its schemes(): its call's Call::fetch.
impl Fetch for Transport {
fn fetch(&self, method: &str, url: &str, headers: Vec<(String, String)>, body: Option<Vec<u8>>) -> BoxFut<'_, Result<Response, String>> {
self.call.fetch(method, url, headers, body)
}
}
/// Every scheme the transports fetch, "<scheme>:" -> that transport: run::Http::schemes takes it as is.
pub fn fetchers(transports: &[Transport]) -> HashMap<String, Arc<dyn Fetch>> {
transports.iter().flat_map(|t| t.schemes().iter().map(move |s| (format!("{s}:"), Arc::new(t.clone()) as Arc<dyn Fetch>))).collect()
}
/// The transports a host was built with.
pub type Transports = Vec<Transport>;
/// Every NSID the transports provide: what module and composition loading may count on (a hook a
/// host transport satisfies), known before any call.
/// run::Options.provides takes it as is.
pub fn provides(transports: &[Transport]) -> HashSet<String> {
transports.iter().flat_map(|t| t.provides.iter().map(|n| n.to_string())).collect()
}
/// The transport an NSID names, com.fedfork.exec.<name>.connect -> <name>: "built without <name>".
pub fn name(nsid: &str) -> Option<&str> {
nsid.strip_prefix(PSEUDO)?.strip_suffix(".connect").filter(|n| !n.is_empty() && !n.contains('.'))
}
/// The call-time refusal of a transport connect this host was built without (the load-time check is
/// the caller's, over provides()): "<nsid>: not available on this host (built without <name>)".
pub fn unavailable(nsid: &str) -> Option<String> {
name(nsid).map(|name| format!("{nsid}: not available on this host (built without {name})"))
}
/// Routes the NSIDs a transport provides to it and everything else to inner. listed: the module record
/// lists its calls; one that lists none may call anything, so it gets no transport (the host's keys
/// stay out of it), as it gets no attest.
pub struct TransportCall {
pub transports: Transports,
pub listed: bool,
pub inner: Arc<dyn Call>,
}
impl TransportCall {
fn route(&self, nsid: &str) -> Result<&Arc<dyn Call>, String> {
match self.transports.iter().find(|t| t.provides.contains(&nsid)) {
None => Ok(&self.inner),
Some(_) if !self.listed => Err(format!("{nsid} needs a module record that lists its calls")),
Some(t) => Ok(&t.call),
}
}
}
impl TransportCall {
/// A did#id call with endpoints: the first endpoint of a scheme a transport fetches (not https: HostCall
/// takes that), with a service-auth token aud did#id the inner session mints (the module never sees it).
async fn peer(&self, nsid: &str, request: &Request) -> Option<Result<Value, String>> {
let (Some(endpoints), Some(aud)) = (request.endpoints.as_ref()?.as_array(), request.service.as_deref()) else { return None };
let (base, transport) = endpoints.iter().find_map(|e| {
let (kind, address) = (e["kind"].as_str()?, e["address"].as_str()?);
let t = self.transports.iter().find(|t| kind != "https" && t.schemes().contains(&kind))?;
Some((format!("{kind}://{address}"), t))
})?;
let params = json!({ "aud": aud, "lxm": nsid }).as_object().cloned();
let minted = self.inner.call("com.atproto.server.getServiceAuth".into(), Request { params, signal: request.signal.clone(), ..Default::default() }).await;
Some(async {
let token = minted?.and_then(|a| a["token"].as_str().map(String::from)).filter(|t| !t.is_empty()).ok_or("getServiceAuth answered no service-auth token")?;
crate::host::bearer_call(transport, &base, nsid, request.params.as_ref(), crate::host::xrpc_body(request.input.as_ref(), request.encoding.as_deref())?, &token).await
}.await)
}
}
impl Call for TransportCall {
fn call(&self, nsid: String, request: Request) -> BoxFut<'_, Result<Option<Value>, String>> {
Box::pin(async move {
if !nsid.starts_with(PSEUDO) {
if let Some(answer) = self.peer(&nsid, &request).await {
return answer.map(Some);
}
}
self.route(&nsid)?.call(nsid, request).await
})
}
fn subscribe(&self, nsid: String, request: Request) -> BoxFut<'_, Result<Sub, String>> {
Box::pin(async move { self.route(&nsid)?.subscribe(nsid, request).await })
}
}
#[cfg(test)]
mod tests {
use super::*;
use serde_json::json;
struct Named(&'static str);
impl Call for Named {
fn call(&self, nsid: String, _: Request) -> BoxFut<'_, Result<Option<Value>, String>> {
Box::pin(async move { Ok(Some(json!([self.0, nsid]))) })
}
fn subscribe(&self, nsid: String, _: Request) -> BoxFut<'_, Result<Sub, String>> {
Box::pin(async move { Err(format!("{} {nsid}", self.0)) })
}
}
#[tokio::test]
async fn transports_take_what_they_provide_and_refuse_unlisted_modules() {
let call = |listed| TransportCall { transports: vec![Transport { provides: &["com.fedfork.exec.iroh.connect"], call: Arc::new(Named("iroh")) }], listed, inner: Arc::new(Named("inner")) };
let iroh = "com.fedfork.exec.iroh.connect";
assert_eq!(provides(&call(true).transports), HashSet::from([iroh.to_string()]));
assert_eq!(call(true).call(iroh.into(), Request::default()).await.unwrap(), Some(json!(["iroh", iroh])));
assert_eq!(call(true).subscribe(iroh.into(), Request::default()).await.err().unwrap(), format!("iroh {iroh}"));
for other in ["com.fedfork.exec.webrtc.connect", "com.fedfork.exec.iroh.other", "com.atproto.repo.getRecord"] {
assert_eq!(call(true).call(other.into(), Request::default()).await.unwrap(), Some(json!(["inner", other])));
}
assert_eq!(call(false).call(iroh.into(), Request::default()).await.unwrap_err(), format!("{iroh} needs a module record that lists its calls"));
assert_eq!(unavailable(iroh).unwrap(), "com.fedfork.exec.iroh.connect: not available on this host (built without iroh)");
assert_eq!(unavailable("com.fedfork.exec.webrtc.connect").unwrap(), "com.fedfork.exec.webrtc.connect: not available on this host (built without webrtc)");
assert!(fetchers(&call(true).transports).is_empty());
for no in ["com.fedfork.exec.attest", "com.fedfork.exec.didkey.sign", "com.fedfork.exec.a.b.connect", "x.y.connect"] {
assert_eq!(unavailable(no), None, "{no}");
}
}
// JS host-call.test.mjs "a did#id call with endpoints"
struct Peer(std::sync::Mutex<Vec<Value>>);
impl Call for Peer {
fn call(&self, nsid: String, request: Request) -> BoxFut<'_, Result<Option<Value>, String>> {
Box::pin(async move {
self.0.lock().unwrap().push(json!([nsid, request.params, request.endpoints]));
Ok(Some(json!({ "token": "jwt1", "via": "inner" })))
})
}
fn subscribe(&self, nsid: String, _: Request) -> BoxFut<'_, Result<Sub, String>> {
Box::pin(async move { Err(nsid) })
}
fn schemes(&self) -> &'static [&'static str] {
&["iroh"]
}
fn fetch(&self, method: &str, url: &str, headers: Vec<(String, String)>, body: Option<Vec<u8>>) -> BoxFut<'_, Result<Response, String>> {
self.0.lock().unwrap().push(json!([method, url, headers, String::from_utf8(body.unwrap_or_default()).unwrap()]));
Box::pin(async { Ok(Response { status: 200, headers: vec![("content-type".into(), "application/json".into())], body: br#"{"via":"iroh"}"#.to_vec() }) })
}
}
#[tokio::test]
async fn a_did_service_call_with_endpoints_goes_to_a_transport_scheme_with_service_auth_else_inner() {
let (iroh, inner) = (Arc::new(Peer(Default::default())), Arc::new(Peer(Default::default())));
let call = TransportCall { transports: vec![Transport { provides: &[], call: iroh.clone() }], listed: true, inner: inner.clone() };
let (nsid, aud) = ("com.publicdomainrelay.temp.market.submitRfp", "did:plc:bidder#pdr_temp_market");
let request = |endpoints: Value| Request { service: Some(aud.into()), endpoints: Some(endpoints), input: Some(json!({ "a": 1 })), ..Default::default() };
let both = json!([{ "kind": "https", "address": "https://bidder.example" }, { "kind": "iroh", "address": "endpointabc234" }]);
assert_eq!(call.call(nsid.into(), request(both)).await.unwrap(), Some(json!({ "via": "iroh" })));
assert_eq!(
*iroh.0.lock().unwrap(),
vec![json!(["POST", format!("iroh://endpointabc234/xrpc/{nsid}"), [["authorization", "Bearer jwt1"], ["content-type", "application/json"]], r#"{"a":1}"#])]
);
let https = json!([{ "kind": "https", "address": "https://bidder.example" }]);
assert_eq!(call.call(nsid.into(), request(https.clone())).await.unwrap(), Some(json!({ "token": "jwt1", "via": "inner" })));
assert_eq!(
*inner.0.lock().unwrap(),
vec![json!(["com.atproto.server.getServiceAuth", { "aud": aud, "lxm": nsid }, null]), json!([nsid, null, https])]
);
}
}
