Web API interface

First implementation of the Web API interface, which can be used to
manage pubkey to APNS token relationships.

src/api_server/api_server.rs

@@ -0,0 +1,47 @@
+use hyper::{server::conn::http1, service::service_fn};
+use hyper_util::rt::TokioIo;
+use std::sync::Arc;
+use tokio::net::TcpListener;
+use log;
+use tokio::sync::Mutex;
+use crate::notification_manager::NotificationManager;
+use super::api_request_handler::APIHandler;
+
+pub struct APIServer {
+    host: String,
+    port: String,
+    api_handler: APIHandler,
+}
+
+impl APIServer {
+    pub async fn run(host: String, port: String, notification_manager: Arc<Mutex<NotificationManager>>, base_url: String) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+        let api_handler = APIHandler::new(notification_manager, base_url);
+        let server = APIServer {
+            host,
+            port,
+            api_handler,
+        };
+        server.start().await
+    }
+    
+    async fn start(&self) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+        let address = format!("{}:{}", self.host, self.port);
+        let listener = TcpListener::bind(&address).await?;
+        
+        log::info!("HTTP server running at {}", address);
+        
+        loop {
+            let (stream, _) = listener.accept().await?;
+            let io = TokioIo::new(stream);
+            let api_handler = self.api_handler.clone();
+    
+            tokio::task::spawn(async move {
+                let service = service_fn(|req| api_handler.handle_http_request(req));
+    
+                if let Err(err) = http1::Builder::new().serve_connection(io, service).await {
+                    log::error!("Failed to serve connection: {:?}", err);
+                }
+            });
+        }
+    }
+}