From 4e216701c0fd606a9b2e2c2cfda8d04613955e9a Mon Sep 17 00:00:00 2001
From: Nikolay Kim <fafhrd91@gmail.com>
Date: Sun, 29 Oct 2017 21:39:59 -0700
Subject: [PATCH] better handler function ergonimics

---
 examples/basic.rs    | 19 ++++++++++---------
 src/application.rs   |  2 +-
 src/error.rs         |  7 +++++++
 src/lib.rs           |  2 +-
 src/resource.rs      |  6 ++++--
 tests/test_server.rs |  4 ++--
 6 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/examples/basic.rs b/examples/basic.rs
index ab976b721..0339335e0 100644
--- a/examples/basic.rs
+++ b/examples/basic.rs
@@ -12,13 +12,14 @@ fn index(req: &mut HttpRequest, _payload: Payload, state: &()) -> HttpResponse {
 }
 
 /// handle with path parameters like `/name/{name}/`
-fn with_param(req: &mut HttpRequest, _payload: Payload, state: &()) -> HttpResponse {
+fn with_param(req: &mut HttpRequest, _payload: Payload, state: &())
+              -> HandlerResult<HttpResponse>
+{
     println!("{:?}", req);
 
-    HttpResponse::builder(StatusCode::OK)
-        .content_type("test/plain")
-        .body(format!("Hello {}!", req.match_info().get("name").unwrap()))
-        .unwrap()
+    Ok(HttpResponse::builder(StatusCode::OK)
+       .content_type("test/plain")
+       .body(format!("Hello {}!", req.match_info().get("name").unwrap()))?)
 }
 
 fn main() {
@@ -38,10 +39,10 @@ fn main() {
             .resource("/", |r| r.handler(Method::GET, |req, _, _| {
                 println!("{:?}", req);
 
-                httpcodes::HTTPFound
-                    .builder()
-                    .header("LOCATION", "/index.html")
-                    .body(Body::Empty)
+                Ok(httpcodes::HTTPFound
+                   .builder()
+                   .header("LOCATION", "/index.html")
+                   .body(Body::Empty)?)
             }))
             // static files
             .route_handler("/static", StaticFiles::new("examples/static/", true)))
diff --git a/src/application.rs b/src/application.rs
index 2bfa6dba0..f3acb8697 100644
--- a/src/application.rs
+++ b/src/application.rs
@@ -180,7 +180,7 @@ impl<S> ApplicationBuilder<S> where S: 'static {
     ///         .resource("/test", |r| {
     ///              r.get::<MyRoute>();
     ///              r.handler(Method::HEAD, |req, payload, state| {
-    ///                  httpcodes::HTTPMethodNotAllowed
+    ///                  Ok(httpcodes::HTTPMethodNotAllowed)
     ///              });
     ///         })
     ///         .finish();
diff --git a/src/error.rs b/src/error.rs
index 25223a4e1..fb64456d2 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -123,6 +123,13 @@ impl From<HttpError> for HttpResponse {
     }
 }
 
+/// Return `InternalServerError` for `io::Error`
+impl From<IoError> for HttpResponse {
+    fn from(err: IoError) -> Self {
+        HttpResponse::from_error(StatusCode::INTERNAL_SERVER_ERROR, err)
+    }
+}
+
 /// Return `BadRequest` for `cookie::ParseError`
 impl From<cookie::ParseError> for HttpResponse {
     fn from(err: cookie::ParseError) -> Self {
diff --git a/src/lib.rs b/src/lib.rs
index 75cdddf2d..af37f5be1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -52,7 +52,7 @@ pub use httprequest::{HttpRequest, UrlEncoded};
 pub use httpresponse::{HttpResponse, HttpResponseBuilder};
 pub use payload::{Payload, PayloadItem, PayloadError};
 pub use route::{Route, RouteFactory, RouteHandler, RouteResult};
-pub use resource::{Reply, Resource};
+pub use resource::{Reply, Resource, HandlerResult};
 pub use recognizer::{Params, RouteRecognizer};
 pub use logger::Logger;
 pub use server::HttpServer;
diff --git a/src/resource.rs b/src/resource.rs
index 5d55665bd..d3a26175b 100644
--- a/src/resource.rs
+++ b/src/resource.rs
@@ -15,6 +15,9 @@ use httprequest::HttpRequest;
 use httpresponse::HttpResponse;
 use httpcodes::{HTTPNotFound, HTTPMethodNotAllowed};
 
+/// Result of a resource handler function
+pub type HandlerResult<T> = Result<T, HttpResponse>;
+
 /// Http resource
 ///
 /// `Resource` is an entry in route table which corresponds to requested URL.
@@ -48,7 +51,6 @@ impl<S> Default for Resource<S> {
     }
 }
 
-
 impl<S> Resource<S> where S: 'static {
 
     pub(crate) fn default_not_found() -> Self {
@@ -66,7 +68,7 @@ impl<S> Resource<S> where S: 'static {
 
     /// Register handler for specified method.
     pub fn handler<F, R>(&mut self, method: Method, handler: F)
-        where F: Fn(&mut HttpRequest, Payload, &S) -> R + 'static,
+        where F: Fn(&mut HttpRequest, Payload, &S) -> HandlerResult<R> + 'static,
               R: Into<HttpResponse> + 'static,
     {
         self.routes.insert(method, Box::new(FnHandler::new(handler)));
diff --git a/tests/test_server.rs b/tests/test_server.rs
index 66042b211..085576897 100644
--- a/tests/test_server.rs
+++ b/tests/test_server.rs
@@ -16,7 +16,7 @@ fn create_server<T, A>() -> HttpServer<T, A, Application<()>> {
         vec![Application::default("/")
              .resource("/", |r|
                        r.handler(Method::GET, |_, _, _| {
-                           httpcodes::HTTPOk
+                           Ok(httpcodes::HTTPOk)
                        }))
              .finish()])
 }
@@ -96,7 +96,7 @@ fn test_middlewares() {
                                             finish: act_num3})
                  .resource("/", |r|
                            r.handler(Method::GET, |_, _, _| {
-                               httpcodes::HTTPOk
+                               Ok(httpcodes::HTTPOk)
                            }))
                  .finish()])
             .serve::<_, ()>("127.0.0.1:58904").unwrap();