use try_future crate to simplify async logic

Cargo.lock

@@ -716,6 +716,7 @@ dependencies = [
  "tokio-core 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-service 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "try_future 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -877,6 +878,14 @@ dependencies = [
  "serde 1.0.27 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "try_future"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "futures 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "unicase"
 version = "2.1.0"
@@ -1056,6 +1065,7 @@ dependencies = [
 "checksum tokio-service 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "24da22d077e0f15f55162bdbdc661228c1581892f52074fb242678d015b45162"
 "checksum tokio-tls 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "772f4b04e560117fe3b0a53e490c16ddc8ba6ec437015d91fa385564996ed913"
 "checksum toml 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)" = "a7540f4ffc193e0d3c94121edb19b055670d369f77d5804db11ae053a45b6e7e"
+"checksum try_future 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "b5991a93204dab99f8f1f8ac657eb070315dbd71a79f15fa4f86d983fa880545"
 "checksum unicase 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "284b6d3db520d67fbe88fd778c21510d1b0ba4a551e5d0fbb023d33405f6de8a"
 "checksum unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8c1f860d7d29cf02cb2f3f359fd35991af3d30bac52c57d265a3c461074cb4dc"
 "checksum unreachable 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1f2ae5ddb18e1c92664717616dd9549dde73f539f01bd7b77c2edb2446bdff91"

Cargo.toml

@@ -25,6 +25,7 @@ slog-json = "2.2.0"
 tokio-core = "0.1.12"
 tokio-service = "0.1.0"
 toml = "0.4.5"
+try_future = "0.1.1"
 
 [dependencies.badge]
 version = "0.2.0"

src/interactors/crates.rs

@@ -71,8 +71,6 @@ impl<S> Service for QueryCrate<S>
     type Future = Box<Future<Item=Self::Response, Error=Self::Error>>;
 
     fn call(&self,  crate_name: CrateName) -> Self::Future {
-        let service = self.0.clone();
-
         let lower_name = crate_name.as_ref().to_lowercase();
 
         let path = match lower_name.len() {
@@ -82,17 +80,17 @@ impl<S> Service for QueryCrate<S>
             _ => format!("{}/{}/{}", &lower_name[0..2], &lower_name[2..4], lower_name),
         };
 
-        let uri_future = format!("{}/master/{}", CRATES_INDEX_BASE_URI, path)
+        let uri = try_future_box!(format!("{}/master/{}", CRATES_INDEX_BASE_URI, path)
-            .parse::<Uri>().into_future().from_err();
+            .parse::<Uri>());
 
-        Box::new(uri_future.and_then(move |uri| {
         let request = Request::new(Method::Get, uri.clone());
 
-            service.call(request).from_err().and_then(move |response| {
+        Box::new(self.0.call(request).from_err().and_then(move |response| {
             let status = response.status();
             if !status.is_success() {
-                    future::Either::A(future::err(format_err!("Status code {} for URI {}", status, uri)))
+                try_future!(Err(format_err!("Status code {} for URI {}", status, uri)));
-                } else {
+            }
+
             let body_future = response.body().concat2().from_err();
             let decode_future = body_future.and_then(move |body| {
                 let string_body = str::from_utf8(body.as_ref())?;
@@ -103,10 +101,10 @@ impl<S> Service for QueryCrate<S>
                     .collect::<Result<_, _>>()?;
                 Ok(packages)
             });
-                    let convert_future = decode_future.and_then(move |pkgs| convert_pkgs(&crate_name, pkgs));
+
-                    future::Either::B(convert_future)
+            decode_future
-                }
+                .and_then(move |pkgs| convert_pkgs(&crate_name, pkgs))
-            })
+                .into()
         }))
     }
 }

src/interactors/github.rs

@@ -1,5 +1,5 @@
 use failure::Error;
-use futures::{Future, IntoFuture, Stream, future};
+use futures::{Future, Stream};
 use hyper::{Error as HyperError, Method, Request, Response, Uri};
 use hyper::header::UserAgent;
 use relative_path::RelativePathBuf;
@@ -51,31 +51,27 @@ impl<S> Service for GetPopularRepos<S>
     type Future = Box<Future<Item=Self::Response, Error=Self::Error>>;
 
     fn call(&self, _req: ()) -> Self::Future {
-        let service = self.0.clone();
+        let uri = try_future_box!(format!("{}/search/repositories?q=language:rust&sort=stars", GITHUB_API_BASE_URI)
+            .parse::<Uri>());
 
-        let uri_future = format!("{}/search/repositories?q=language:rust&sort=stars", GITHUB_API_BASE_URI)
-            .parse().into_future().from_err();
-
-        Box::new(uri_future.and_then(move |uri| {
         let mut request = Request::new(Method::Get, uri);
         request.headers_mut().set(UserAgent::new("deps.rs"));
 
-            service.call(request).from_err().and_then(|response| {
+        Box::new(self.0.call(request).from_err().and_then(|response| {
             let status = response.status();
             if !status.is_success() {
-                    future::Either::A(future::err(format_err!("Status code {} for popular repo search", status)))
+                try_future!(Err(format_err!("Status code {} for popular repo search", status)));
-                } else {
+            }
+
             let body_future = response.body().concat2().from_err();
             let decode_future = body_future
                 .and_then(|body| serde_json::from_slice(body.as_ref()).map_err(|err| err.into()));
-                    future::Either::B(decode_future.and_then(|search_response: GithubSearchResponse| {
+            decode_future.and_then(|search_response: GithubSearchResponse| {
                 search_response.items.into_iter().map(|item| {
                     let path = RepoPath::from_parts("github", &item.owner.login, &item.name)?;
                     Ok(Repository { path, description: item.description })
                 }).collect::<Result<Vec<_>, _>>()
-                    }))
+            }).into()
-                }
-            })
         }))
     }
 }

src/interactors/mod.rs

@@ -1,5 +1,5 @@
 use failure::Error;
-use futures::{Future, IntoFuture, Stream, future};
+use futures::{Future, Stream};
 use hyper::{Error as HyperError, Method, Request, Response};
 use relative_path::RelativePathBuf;
 use tokio_service::Service;
@@ -25,36 +25,32 @@ impl<S> Service for RetrieveFileAtPath<S>
     type Future = Box<Future<Item=Self::Response, Error=Self::Error>>;
 
     fn call(&self, req: Self::Request) -> Self::Future {
-        let service = self.0.clone();
-
         let (repo_path, path) = req;
         let uri = match &repo_path.site {
             &RepoSite::Github => {
-                github::get_manifest_uri(&repo_path, &path)
+                try_future_box!(github::get_manifest_uri(&repo_path, &path))
             },
             &RepoSite::Gitlab => {
-                gitlab::get_manifest_uri(&repo_path, &path)
+                try_future_box!(gitlab::get_manifest_uri(&repo_path, &path))
             },
             &RepoSite::Bitbucket => {
-                bitbucket::get_manifest_uri(&repo_path, &path)
+                try_future_box!(bitbucket::get_manifest_uri(&repo_path, &path))
             }
         };
-        let uri_future = uri.into_future().from_err();
 
-        Box::new(uri_future.and_then(move |uri| {
         let request = Request::new(Method::Get, uri.clone());
 
-            service.call(request).from_err().and_then(move |response| {
+        Box::new(self.0.call(request).from_err().and_then(move |response| {
             let status = response.status();
             if !status.is_success() {
-                    future::Either::A(future::err(format_err!("Status code {} for URI {}", status, uri)))
+                try_future!(Err(format_err!("Status code {} for URI {}", status, uri)));
-                } else {
-                    let body_future = response.body().concat2().from_err();
-                    let decode_future = body_future
-                        .and_then(|body| String::from_utf8(body.to_vec()).map_err(|err| err.into()));
-                    future::Either::B(decode_future)
             }
-            })
+
+            let body_future = response.body().concat2().from_err();
+
+            body_future
+                .and_then(|body| String::from_utf8(body.to_vec()).map_err(|err| err.into()))
+                .into()
         }))
     }
 }

src/main.rs

@@ -25,6 +25,7 @@ extern crate slog_json;
 extern crate tokio_core;
 extern crate tokio_service;
 extern crate toml;
+#[macro_use] extern crate try_future;
 
 mod utils;
 mod models;