Simplifies HTTP client code

lib/src/sparql/http/simple.rs

@@ -3,8 +3,6 @@ use oxhttp::model::{Body, HeaderName, Method, Request};
 use std::io::Result;
 use std::time::Duration;
 
-const USER_AGENT: &str = concat!("Oxigraph/", env!("CARGO_PKG_VERSION"));
-
 pub struct Client {
     client: oxhttp::Client,
 }
@@ -13,23 +11,20 @@ impl Client {
     pub fn new(timeout: Option<Duration>) -> Self {
         let mut client = oxhttp::Client::new();
         client.set_global_timeout(timeout);
+        client
+            .set_user_agent(concat!("Oxigraph/", env!("CARGO_PKG_VERSION")).into())
+            .unwrap();
         Self { client }
     }
 
     pub fn get(&self, url: &str, accept: &str) -> Result<(String, Body)> {
-        let mut request = Request::new(Method::GET, url.parse().map_err(invalid_input_error)?);
-        request.headers_mut().append(
-            HeaderName::ACCEPT,
-            accept.parse().map_err(invalid_input_error)?,
-        );
-        request.headers_mut().append(
-            HeaderName::USER_AGENT,
-            USER_AGENT.parse().map_err(invalid_input_error)?,
-        );
+        let request = Request::builder(Method::GET, url.parse().map_err(invalid_input_error)?)
+            .with_header(HeaderName::ACCEPT, accept)
+            .map_err(invalid_input_error)?
+            .build();
         let response = self.client.request(request)?;
         let content_type = response
-            .headers()
-            .get(&HeaderName::CONTENT_TYPE)
+            .header(&HeaderName::CONTENT_TYPE)
             .ok_or_else(|| invalid_data_error(format!("No Content-Type returned by {}", url)))?
             .to_str()
             .map_err(invalid_data_error)?
@@ -44,23 +39,15 @@ impl Client {
         content_type: &str,
         accept: &str,
     ) -> Result<(String, Body)> {
-        let mut request = Request::new(Method::GET, url.parse().map_err(invalid_input_error)?);
-        request.headers_mut().append(
-            HeaderName::ACCEPT,
-            accept.parse().map_err(invalid_input_error)?,
-        );
-        request.headers_mut().append(
-            HeaderName::USER_AGENT,
-            USER_AGENT.parse().map_err(invalid_input_error)?,
-        );
-        request.headers_mut().append(
-            HeaderName::CONTENT_TYPE,
-            content_type.parse().map_err(invalid_input_error)?,
-        );
-        let response = self.client.request(request.with_body(payload))?;
+        let request = Request::builder(Method::GET, url.parse().map_err(invalid_input_error)?)
+            .with_header(HeaderName::ACCEPT, accept)
+            .map_err(invalid_input_error)?
+            .with_header(HeaderName::CONTENT_TYPE, content_type)
+            .map_err(invalid_input_error)?
+            .with_body(payload);
+        let response = self.client.request(request)?;
         let content_type = response
-            .headers()
-            .get(&HeaderName::CONTENT_TYPE)
+            .header(&HeaderName::CONTENT_TYPE)
             .ok_or_else(|| invalid_data_error(format!("No Content-Type returned by {}", url)))?
             .to_str()
             .map_err(invalid_data_error)?