Add API endpoint to check if known handle.

src/filters.rs

@@ -10,7 +10,8 @@ pub fn search(
     search_image(db.clone(), tree.clone())
         .or(search_hashes(db.clone(), tree.clone()))
         .or(stream_search_image(db.clone(), tree))
-        .or(search_file(db))
+        .or(search_file(db.clone()))
+        .or(check_handle(db))
 }
 
 pub fn search_file(db: Pool) -> impl Filter<Extract = impl Reply, Error = Rejection> + Clone {
@@ -66,6 +67,14 @@ pub fn stream_search_image(
         .and_then(handlers::stream_image)
 }
 
+pub fn check_handle(db: Pool) -> impl Filter<Extract = impl Reply, Error = Rejection> + Clone {
+    warp::path("handle")
+        .and(warp::get())
+        .and(warp::query::<HandleOpts>())
+        .and(with_pool(db))
+        .and_then(handlers::check_handle)
+}
+
 fn with_api_key() -> impl Filter<Extract = (String,), Error = Rejection> + Clone {
     warp::header::<String>("x-api-key")
 }

src/handlers.rs

@@ -290,6 +290,24 @@ pub async fn search_file(
     Ok(warp::reply::json(&matches))
 }
 
+pub async fn check_handle(opts: HandleOpts, db: Pool) -> Result<impl Reply, Rejection> {
+    let db = db.get().await.map_err(map_bb8_err)?;
+
+    let exists = if let Some(handle) = opts.twitter {
+        !db.query(
+            "SELECT 1 FROM twitter_user WHERE lower(data->>'screen_name') = lower($1)",
+            &[&handle],
+        )
+        .await
+        .map_err(map_postgres_err)?
+        .is_empty()
+    } else {
+        false
+    };
+
+    Ok(warp::reply::json(&exists))
+}
+
 #[tracing::instrument]
 pub async fn handle_rejection(err: Rejection) -> Result<impl Reply, std::convert::Infallible> {
     warn!("had rejection");

src/types.rs

@@ -107,3 +107,8 @@ pub struct HashSearchOpts {
     pub hashes: String,
     pub distance: Option<i64>,
 }
+
+#[derive(Debug, Deserialize)]
+pub struct HandleOpts {
+    pub twitter: Option<String>,
+}