Clean up (de)serialization of allowed origins for CORS

The solution could be simpler if
toml-rs/toml-rs#334 were fixed. It
would be even simpler if `serde` supported flattening enum variants,
but it doesn't: serde-rs/serde#1402.

Also:

- Rename config file field from `allowed_foreign_origins` to
  `allowed_origins` since being under the CORS section already
  indicates that it refers to foreign origins.

cnd/src/config/file.rs

@@ -42,12 +42,14 @@ impl File {
                     address: IpAddr::V4(Ipv4Addr::UNSPECIFIED),
                     port: 8000,
                 },
-                cors: None,
+                cors: Some(Cors {
+                    allowed_origins: AllowedOrigins::None(None::None),
+                }),
             },
-            database: None,
-            logging: None,
-            bitcoin: None,
-            ethereum: None,
+            database: Option::None,
+            logging: Option::None,
+            bitcoin: Option::None,
+            ethereum: Option::None,
         }
     }
 }
@@ -71,15 +73,27 @@ pub struct HttpApi {
 
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
 pub struct Cors {
-    pub allowed_foreign_origins: AllowedForeignOrigins,
+    pub allowed_origins: AllowedOrigins,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+#[serde(untagged)]
+pub enum AllowedOrigins {
+    All(All),
+    None(None),
+    Some(Vec<String>),
 }
 
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
 #[serde(rename_all = "lowercase")]
-pub enum AllowedForeignOrigins {
+pub enum All {
     All,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+#[serde(rename_all = "lowercase")]
+pub enum None {
     None,
-    List(Vec<String>),
 }
 
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
@@ -161,7 +175,7 @@ impl File {
 
     fn ensure_directory_exists(config_file: &Path) -> Result<(), config_rs::ConfigError> {
         match config_file.parent() {
-            None => Ok(()),
+            Option::None => Ok(()),
             Some(path) => {
                 if !path.exists() {
                     println!(
@@ -228,7 +242,7 @@ mod tests {
         assert_that(&config_file).is_ok_containing(LoggingOnlyConfig {
             logging: Logging {
                 level: Some(LevelFilter::Debug),
-                structured: None,
+                structured: Option::None,
             },
         });
     }
@@ -278,25 +292,25 @@ mod tests {
     fn cors_deserializes_correctly() {
         let file_contents = vec![
             r#"
-            allowed_foreign_origins = "all"
+            allowed_origins = "all"
             "#,
             r#"
-             allowed_foreign_origins = "none"
+             allowed_origins = "none"
             "#,
             r#"
-             allowed_foreign_origins = { list = ["http://localhost:8000", "https://192.168.1.55:3000"] }
+             allowed_origins = ["http://localhost:8000", "https://192.168.1.55:3000"]
             "#,
         ];
 
         let expected = vec![
             Cors {
-                allowed_foreign_origins: AllowedForeignOrigins::All,
+                allowed_origins: AllowedOrigins::All(All::All),
             },
             Cors {
-                allowed_foreign_origins: AllowedForeignOrigins::None,
+                allowed_origins: AllowedOrigins::None(None::None),
             },
             Cors {
-                allowed_foreign_origins: AllowedForeignOrigins::List(vec![
+                allowed_origins: AllowedOrigins::Some(vec![
                     String::from("http://localhost:8000"),
                     String::from("https://192.168.1.55:3000"),
                 ]),
@@ -319,7 +333,7 @@ mod tests {
     #[test]
     fn complete_logging_section_is_optional() {
         let config_without_logging_section = File {
-            logging: None,
+            logging: Option::None,
             ..File::default()
         };
         let temp_file = temp_toml_file();

cnd/src/config/mod.rs

@@ -6,6 +6,6 @@ mod serde_duration;
 mod settings;
 
 pub use self::{
-    file::{AllowedForeignOrigins, File},
-    settings::Settings,
+    file::File,
+    settings::{AllowedOrigins, Settings},
 };

cnd/src/config/settings.rs

@@ -1,4 +1,4 @@
-use super::file::{AllowedForeignOrigins, Cors, Database, File, Network, Socket};
+use super::file::{self, Database, File, Network, Socket};
 use crate::config::file::{Bitcoin, Ethereum};
 use log::LevelFilter;
 use reqwest::Url;
@@ -25,6 +25,18 @@ pub struct HttpApi {
     pub cors: Cors,
 }
 
+#[derive(Clone, Debug, PartialEq)]
+pub struct Cors {
+    pub allowed_origins: AllowedOrigins,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum AllowedOrigins {
+    All,
+    None,
+    Some(Vec<String>),
+}
+
 #[derive(Clone, Debug, PartialEq, derivative::Derivative)]
 #[derivative(Default)]
 pub struct Logging {
@@ -48,9 +60,20 @@ impl Settings {
             network,
             http_api: HttpApi {
                 socket: http_api.socket,
-                cors: http_api.cors.unwrap_or(Cors {
-                    allowed_foreign_origins: AllowedForeignOrigins::None,
-                }),
+                cors: http_api
+                    .cors
+                    .map(|cors| {
+                        let allowed_origins = match cors.allowed_origins {
+                            file::AllowedOrigins::All(_) => AllowedOrigins::All,
+                            file::AllowedOrigins::None(_) => AllowedOrigins::None,
+                            file::AllowedOrigins::Some(origins) => AllowedOrigins::Some(origins),
+                        };
+
+                        Cors { allowed_origins }
+                    })
+                    .unwrap_or(Cors {
+                        allowed_origins: AllowedOrigins::None,
+                    }),
             },
             database,
             logging: {
@@ -155,7 +178,7 @@ mod tests {
         assert_that(&settings)
             .map(|settings| &settings.http_api.cors)
             .is_equal_to(Cors {
-                allowed_foreign_origins: AllowedForeignOrigins::None,
+                allowed_origins: AllowedOrigins::None,
             })
     }
 }

cnd/src/http_api/route_factory.rs

@@ -1,5 +1,5 @@
 use crate::{
-    config::AllowedForeignOrigins,
+    config::AllowedOrigins,
     db::SaveRfc003Messages,
     http_api,
     network::{Network, SendRequest},
@@ -35,7 +35,7 @@ pub fn create<
 >(
     peer_id: PeerId,
     dependencies: D,
-    allowed_foreign_origins: AllowedForeignOrigins,
+    allowed_origins: &AllowedOrigins,
 ) -> BoxedFilter<(impl Reply,)> {
     let swaps = warp::path(http_api::PATH);
     let rfc003 = swaps.and(warp::path(RFC003));
@@ -46,10 +46,10 @@ pub fn create<
     let cors = warp::cors()
         .allow_methods(vec!["GET", "POST"])
         .allow_header("content-type");
-    let cors = match allowed_foreign_origins {
-        AllowedForeignOrigins::None => cors.allow_origins(Vec::<&str>::new()),
-        AllowedForeignOrigins::All => cors.allow_any_origin(),
-        AllowedForeignOrigins::List(hosts) => {
+    let cors = match allowed_origins {
+        AllowedOrigins::None => cors.allow_origins(Vec::<&str>::new()),
+        AllowedOrigins::All => cors.allow_any_origin(),
+        AllowedOrigins::Some(hosts) => {
             cors.allow_origins::<Vec<&str>>(hosts.iter().map(|host| host.as_str()).collect())
         }
     };

cnd/src/main.rs

@@ -141,7 +141,7 @@ fn spawn_warp_instance<
     let routes = route_factory::create(
         peer_id,
         dependencies,
-        settings.http_api.cors.allowed_foreign_origins.clone(),
+        &settings.http_api.cors.allowed_origins,
     );
 
     let listen_addr = SocketAddr::new(