feat: gRPC authorization for events

closes: https://todo.sr.ht/~gheartsfield/nostr-rs-relay/46

src/nauthz.rs

@@ -0,0 +1,110 @@
+use crate::error::{Error, Result};
+use crate::{event::Event, nip05::Nip05Name};
+use nauthz_grpc::authorization_client::AuthorizationClient;
+use nauthz_grpc::event::TagEntry;
+use nauthz_grpc::{Decision, Event as GrpcEvent, EventReply, EventRequest};
+use tracing::{info, warn};
+
+pub mod nauthz_grpc {
+    tonic::include_proto!("nauthz");
+}
+
+// A decision for the DB to act upon
+pub trait AuthzDecision: Send + Sync {
+    fn permitted(&self) -> bool;
+    fn message(&self) -> Option<String>;
+}
+
+impl AuthzDecision for EventReply {
+    fn permitted(&self) -> bool {
+        self.decision == Decision::Permit as i32
+    }
+    fn message(&self) -> Option<String> {
+        self.message.clone()
+    }
+}
+
+// A connection to an event admission GRPC server
+pub struct EventAuthzService {
+    server_addr: String,
+    conn: Option<AuthorizationClient<tonic::transport::Channel>>,
+}
+
+// conversion of Nip05Names into GRPC type
+impl std::convert::From<Nip05Name> for nauthz_grpc::event_request::Nip05Name {
+    fn from(value: Nip05Name) -> Self {
+        nauthz_grpc::event_request::Nip05Name {
+            local: value.local.clone(),
+            domain: value.domain.clone(),
+        }
+    }
+}
+
+// conversion of event tags into gprc struct
+fn tags_to_protobuf(tags: &Vec<Vec<String>>) -> Vec<TagEntry> {
+    tags.iter()
+        .map(|x| TagEntry { values: x.clone() })
+        .collect()
+}
+
+impl EventAuthzService {
+    pub async fn connect(server_addr: &str) -> EventAuthzService {
+        let mut eas = EventAuthzService {
+            server_addr: server_addr.to_string(),
+            conn: None,
+        };
+        eas.ready_connection().await;
+        eas
+    }
+
+    pub async fn ready_connection(self: &mut Self) {
+        if self.conn.is_none() {
+            let client = AuthorizationClient::connect(self.server_addr.to_string()).await;
+            if let Err(ref msg) = client {
+                warn!("could not connect to nostr authz GRPC server: {:?}", msg);
+            } else {
+                info!("connected to nostr authorization GRPC server");
+            }
+            self.conn = client.ok();
+        }
+    }
+
+    pub async fn admit_event(
+        self: &mut Self,
+        event: &Event,
+        ip: &str,
+        origin: Option<String>,
+        user_agent: Option<String>,
+        nip05: Option<Nip05Name>,
+    ) -> Result<Box<dyn AuthzDecision>> {
+        self.ready_connection().await;
+        let id_blob = hex::decode(&event.id)?;
+        let pubkey_blob = hex::decode(&event.pubkey)?;
+        let sig_blob = hex::decode(&event.sig)?;
+        if let Some(ref mut c) = self.conn {
+            let gevent = GrpcEvent {
+                id: id_blob,
+                pubkey: pubkey_blob,
+                sig: sig_blob,
+                created_at: event.created_at,
+                kind: event.kind,
+                content: event.content.clone(),
+                tags: tags_to_protobuf(&event.tags),
+            };
+            let svr_res = c
+                .event_admit(EventRequest {
+                    event: Some(gevent),
+                    ip_addr: Some(ip.to_string()),
+                    origin,
+                    user_agent,
+                    auth_pubkey: None,
+                    nip05: nip05.map(|x| nauthz_grpc::event_request::Nip05Name::from(x)),
+                })
+                .await?;
+            let reply = svr_res.into_inner();
+            return Ok(Box::new(reply));
+        } else {
+            return Err(Error::AuthzError);
+        }
+    }
+}