From 06a68e758c379366668f2e9951bbbd78098ac15e Mon Sep 17 00:00:00 2001
From: Yuki Kishimoto <yukikishimoto@protonmail.com>
Date: Tue, 11 Jun 2024 16:43:33 -0400
Subject: [PATCH] Add `/event/<id>` endpoint

---
 src/error.rs   |  7 +++++-
 src/handler.rs | 61 ++++++++++++++++++++++++++++++++++----------------
 src/main.rs    |  1 +
 3 files changed, 49 insertions(+), 20 deletions(-)

diff --git a/src/error.rs b/src/error.rs
index 5a07103..566781d 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -23,6 +23,8 @@ where
 pub enum AppError {
     // Too many filters were provided in the request
     FilterError(usize),
+    // Too many filters were provided in the request
+    EventIdNotFound,
     // The request body contained invalid JSON
     JsonRejection(JsonRejection),
     // An Nostr Client error occurred
@@ -38,8 +40,11 @@ impl IntoResponse for AppError {
         let (status, message) = match self {
             AppError::FilterError(max_filters) => (
                 StatusCode::BAD_REQUEST,
-                format!("Too many filters (max allowed {})", max_filters).to_string(),
+                format!("Too many filters (max allowed {max_filters})"),
             ),
+            AppError::EventIdNotFound => {
+                (StatusCode::BAD_REQUEST, String::from("Event ID not found"))
+            }
             AppError::JsonRejection(rejection) => (rejection.status(), rejection.body_text()),
             AppError::NostrClientError(err) => (StatusCode::BAD_REQUEST, err.to_string()),
             AppError::NostrEventError(err) => (StatusCode::BAD_REQUEST, err.to_string()),
diff --git a/src/handler.rs b/src/handler.rs
index 47b4d7d..768ee9d 100644
--- a/src/handler.rs
+++ b/src/handler.rs
@@ -1,17 +1,23 @@
 // Copyright (c) 2023 Nostr Development Kit Devs
 // Distributed under the MIT software license
 
-use axum::extract::State;
+use axum::extract::{Path, State};
 use axum::response::Json;
 use nostr_sdk::hashes::sha256::Hash as Sha256Hash;
 use nostr_sdk::hashes::Hash;
-use nostr_sdk::{Event, Filter};
+use nostr_sdk::{Event, EventId, Filter};
 use redis::AsyncCommands;
+use serde::Deserialize;
 use serde_json::{json, Value};
 
 use crate::error::{AppError, AppJson};
 use crate::AppState;
 
+#[derive(Deserialize)]
+pub struct GetEventByIdParams {
+    event_id: EventId,
+}
+
 pub async fn ping() -> Json<Value> {
     Json(json!({
         "success": true,
@@ -44,19 +50,44 @@ pub async fn get_events(
         return Err(AppError::FilterError(state.config.limit.max_filters));
     }
 
+    let events: Vec<Event> = get_events_by_filters(state, filters).await?;
+
+    Ok(AppJson(json!({
+        "success": true,
+        "message": format!("Got {} events", events.len()),
+        "data": events,
+    })))
+}
+
+pub async fn get_event_by_id(
+    state: State<AppState>,
+    path: Path<GetEventByIdParams>,
+) -> Result<AppJson<Value>, AppError> {
+    let event_id: EventId = path.event_id;
+    let filter: Filter = Filter::new().id(event_id);
+    let filters: Vec<Filter> = vec![filter];
+    let events: Vec<Event> = get_events_by_filters(state, filters).await?;
+    let event: &Event = events.first().ok_or(AppError::EventIdNotFound)?;
+    Ok(AppJson(json!({
+        "success": true,
+        "message": "Got 1 events",
+        "data": event,
+    })))
+}
+
+async fn get_events_by_filters(
+    state: State<AppState>,
+    filters: Vec<Filter>,
+) -> Result<Vec<Event>, AppError> {
     if let Some(redis) = &state.redis {
-        let mut connection = redis.get_multiplexed_async_connection().await.unwrap();
+        let mut connection = redis.get_multiplexed_async_connection().await.unwrap(); // TODO: remove unwrap
         let hash: String = Sha256Hash::hash(format!("{filters:?}").as_bytes()).to_string();
         let exists = connection.exists::<&str, bool>(&hash).await?;
         if exists {
             let result = connection.get(&hash).await?;
             let bytes: Vec<u8> = result;
-            let events: Vec<Event> = bincode::deserialize(&bytes).unwrap();
-            Ok(AppJson(json!({
-                "success": true,
-                "message": format!("Got {} events", events.len()),
-                "data": events,
-            })))
+            let events: Vec<Event> = bincode::deserialize(&bytes).unwrap(); // TODO: remove unwrap
+            Ok(events)
         } else {
             let events = state.client.get_events_of(filters, None).await?;
             let encoded: Vec<u8> = bincode::serialize(&events).unwrap();
@@ -64,19 +95,11 @@ pub async fn get_events(
                 .set_ex(hash, encoded, state.config.redis.expiration)
                 .await
                 .unwrap();
-            Ok(AppJson(json!({
-                "success": true,
-                "message": format!("Got {} events", events.len()),
-                "data": events,
-            })))
+            Ok(events)
         }
     } else {
         // TODO: add a timeout
         let events = state.client.get_events_of(filters, None).await?;
-        Ok(AppJson(json!({
-            "success": true,
-            "message": format!("Got {} events", events.len()),
-            "data": events,
-        })))
+        Ok(events)
     }
 }
diff --git a/src/main.rs b/src/main.rs
index eca70a6..5f2a4ba 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -53,6 +53,7 @@ async fn main() -> Result<()> {
     let app = Router::new()
         .route("/ping", get(handler::ping))
         .route("/event", post(handler::publish_event))
+        .route("/event/:event_id", get(handler::get_event_by_id))
         .route("/events", post(handler::get_events))
         .layer(if config.network.permissive_cors {
             CorsLayer::permissive()