First pass at Extractors.

examples/extractors/src/main.rs

@@ -0,0 +1,48 @@
+use actix_web::{web, App, FromRequest, HttpRequest, HttpServer, Responder};
+use futures::future::Future;
+use serde::Deserialize;
+
+// mod custom_handler;
+mod form;
+mod json_one;
+mod json_two;
+mod multiple;
+mod path_one;
+mod path_two;
+mod query;
+
+#[derive(Deserialize, Debug)]
+struct MyInfo {
+    username: String,
+    id: u32,
+}
+
+// <main>
+// Option 1:  passed as a parameter to a handler function
+fn index(path: web::Path<(String, String)>, json: web::Json<MyInfo>) -> impl Responder {
+    format!("{} {} {} {}", path.0, path.1, json.id, json.username)
+}
+
+// Option 2:  accessed by calling extract() on the Extractor
+fn extract(req: HttpRequest) -> impl Responder {
+    let params = web::Path::<(String, String)>::extract(&req).unwrap();
+
+    let info = web::Json::<MyInfo>::extract(&req)
+        .wait()
+        .expect("Err with reading json.");
+
+    format!("{} {} {} {}", params.0, params.1, info.username, info.id)
+}
+// </main>
+
+fn main() {
+    HttpServer::new(|| {
+        App::new()
+            .route("/{name}/{id}", web::post().to(index))
+            .route("/{name}/{id}/extract", web::post().to(extract))
+    })
+    .bind("127.0.0.1:8088")
+    .unwrap()
+    .run()
+    .unwrap();
+}