aquatic_http: use Cow<_> for FailureResponse.failure_reason

aquatic_http/src/lib/network/mod.rs

@@ -233,9 +233,7 @@ pub fn handle_connection_read_event(
                         peer_addr: established.peer_addr,
                     };
 
-                    let response = FailureResponse {
-                        failure_reason: "invalid request".to_string(),
-                    };
+                    let response = FailureResponse::new("Invalid request");
 
                     local_responses.push((meta, Response::Failure(response)));
 

aquatic_http_protocol/src/response.rs

@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::io::Write;
 use std::net::{Ipv4Addr, Ipv6Addr};
 
@@ -131,11 +132,11 @@ impl ScrapeResponse {
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct FailureResponse {
     #[serde(rename = "failure reason")]
-    pub failure_reason: String,
+    pub failure_reason: Cow<'static, str>,
 }
 
 impl FailureResponse {
-    pub fn new(reason: &str) -> Self {
+    pub fn new<S: Into<Cow<'static, str>>>(reason: S) -> Self {
         Self {
             failure_reason: reason.into(),
         }
@@ -248,7 +249,7 @@ impl quickcheck::Arbitrary for ScrapeResponse {
 impl quickcheck::Arbitrary for FailureResponse {
     fn arbitrary(g: &mut quickcheck::Gen) -> Self {
         Self {
-            failure_reason: String::arbitrary(g),
+            failure_reason: String::arbitrary(g).into(),
         }
     }
 }