Split the server into three crates (#56)

This will make it easier to build variations on the server, or embed it
into larger projects.

server/src/lib.rs

@@ -0,0 +1,64 @@
+#![deny(clippy::all)]
+
+mod api;
+
+use actix_web::{get, middleware, web, Responder};
+use api::{api_scope, ServerState};
+use std::sync::Arc;
+use taskchampion_sync_server_core::{ServerConfig, Storage};
+
+#[get("/")]
+async fn index() -> impl Responder {
+    format!("TaskChampion sync server v{}", env!("CARGO_PKG_VERSION"))
+}
+
+/// A Server represents a sync server.
+#[derive(Clone)]
+pub struct Server {
+    server_state: Arc<ServerState>,
+}
+
+impl Server {
+    /// Create a new sync server with the given storage implementation.
+    pub fn new(config: ServerConfig, storage: Box<dyn Storage>) -> Self {
+        Self {
+            server_state: Arc::new(ServerState { config, storage }),
+        }
+    }
+
+    /// Get an Actix-web service for this server.
+    pub fn config(&self, cfg: &mut web::ServiceConfig) {
+        cfg.service(
+            web::scope("")
+                .app_data(web::Data::new(self.server_state.clone()))
+                .wrap(
+                    middleware::DefaultHeaders::new().add(("Cache-Control", "no-store, max-age=0")),
+                )
+                .service(index)
+                .service(api_scope()),
+        );
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use actix_web::{test, App};
+    use pretty_assertions::assert_eq;
+    use taskchampion_sync_server_core::InMemoryStorage;
+
+    #[actix_rt::test]
+    async fn test_cache_control() {
+        let server = Server::new(Default::default(), Box::new(InMemoryStorage::new()));
+        let app = App::new().configure(|sc| server.config(sc));
+        let app = test::init_service(app).await;
+
+        let req = test::TestRequest::get().uri("/").to_request();
+        let resp = test::call_service(&app, req).await;
+        assert!(resp.status().is_success());
+        assert_eq!(
+            resp.headers().get("Cache-Control").unwrap(),
+            &"no-store, max-age=0".to_string()
+        )
+    }
+}