Server: avoids big if let blocks

server/src/main.rs

@@ -244,7 +244,8 @@ fn handle_request(request: &mut Request, store: Store) -> Result<Response, HttpE
             configure_and_evaluate_sparql_query(store, &[url_query(request)], None, request)
         }
         ("/query", "POST") => {
-            if let Some(content_type) = content_type(request) {
+            let content_type =
+                content_type(request).ok_or_else(|| bad_request("No Content-Type given"))?;
             if content_type == "application/sparql-query" {
                 let mut buffer = String::new();
                 request
@@ -274,12 +275,10 @@ fn handle_request(request: &mut Request, store: Store) -> Result<Response, HttpE
             } else {
                 Err(unsupported_media_type(&content_type))
             }
-            } else {
-                Err(bad_request("No Content-Type given"))
-            }
         }
         ("/update", "POST") => {
-            if let Some(content_type) = content_type(request) {
+            let content_type =
+                content_type(request).ok_or_else(|| bad_request("No Content-Type given"))?;
             if content_type == "application/sparql-update" {
                 let mut buffer = String::new();
                 request
@@ -309,9 +308,6 @@ fn handle_request(request: &mut Request, store: Store) -> Result<Response, HttpE
             } else {
                 return Err(unsupported_media_type(&content_type));
             }
-            } else {
-                Err(bad_request("No Content-Type given"))
-            }
         }
         (path, "GET") if path.starts_with("/store") => {
             if let Some(target) = store_target(request)? {
@@ -364,9 +360,11 @@ fn handle_request(request: &mut Request, store: Store) -> Result<Response, HttpE
             }
         }
         (path, "PUT") if path.starts_with("/store") => {
-            if let Some(content_type) = content_type(request) {
+            let content_type =
+                content_type(request).ok_or_else(|| bad_request("No Content-Type given"))?;
             if let Some(target) = store_target(request)? {
-                    if let Some(format) = GraphFormat::from_media_type(&content_type) {
+                let format = GraphFormat::from_media_type(&content_type)
+                    .ok_or_else(|| unsupported_media_type(&content_type))?;
                 let new = !match &target {
                     NamedGraphName::NamedNode(target) => {
                         if store
@@ -404,19 +402,13 @@ fn handle_request(request: &mut Request, store: Store) -> Result<Response, HttpE
                 })
                 .build())
             } else {
-                        Err(unsupported_media_type(&content_type))
-                    }
-                } else if let Some(format) = DatasetFormat::from_media_type(&content_type) {
+                let format = DatasetFormat::from_media_type(&content_type)
+                    .ok_or_else(|| unsupported_media_type(&content_type))?;
                 store.clear().map_err(internal_server_error)?;
                 store
                     .load_dataset(BufReader::new(request.body_mut()), format, None)
                     .map_err(internal_server_error)?;
                 Ok(Response::builder(Status::NO_CONTENT).build())
-                } else {
-                    Err(unsupported_media_type(&content_type))
-                }
-            } else {
-                Err(bad_request("No Content-Type given"))
             }
         }
         (path, "DELETE") if path.starts_with("/store") => {
@@ -447,7 +439,8 @@ fn handle_request(request: &mut Request, store: Store) -> Result<Response, HttpE
             Ok(Response::builder(Status::NO_CONTENT).build())
         }
         (path, "POST") if path.starts_with("/store") => {
-            if let Some(content_type) = content_type(request) {
+            let content_type =
+                content_type(request).ok_or_else(|| bad_request("No Content-Type given"))?;
             if let Some(target) = store_target(request)? {
                 if let Some(format) = GraphFormat::from_media_type(&content_type) {
                     let new = assert_that_graph_exists(&store, &target).is_ok();
@@ -474,8 +467,7 @@ fn handle_request(request: &mut Request, store: Store) -> Result<Response, HttpE
                     .map_err(bad_request)?;
                 Ok(Response::builder(Status::NO_CONTENT).build())
             } else if let Some(format) = GraphFormat::from_media_type(&content_type) {
-                    let graph =
-                        resolve_with_base(request, &format!("/store/{:x}", random::<u128>()))?;
+                let graph = resolve_with_base(request, &format!("/store/{:x}", random::<u128>()))?;
                 store
                     .load_graph(BufReader::new(request.body_mut()), format, &graph, None)
                     .map_err(bad_request)?;
@@ -486,9 +478,6 @@ fn handle_request(request: &mut Request, store: Store) -> Result<Response, HttpE
             } else {
                 Err(unsupported_media_type(&content_type))
             }
-            } else {
-                Err(bad_request("No Content-Type given"))
-            }
         }
         (path, "HEAD") if path.starts_with("/store") => {
             if let Some(target) = store_target(request)? {
@@ -553,7 +542,7 @@ fn configure_and_evaluate_sparql_query(
             }
         }
     }
-    if let Some(query) = query {
+    let query = query.ok_or_else(|| bad_request("You should set the 'query' parameter"))?;
     evaluate_sparql_query(
         store,
         query,
@@ -562,9 +551,6 @@ fn configure_and_evaluate_sparql_query(
         named_graph_uris,
         request,
     )
-    } else {
-        Err(bad_request("You should set the 'query' parameter"))
-    }
 }
 
 fn evaluate_sparql_query(
@@ -685,7 +671,7 @@ fn configure_and_evaluate_sparql_update(
             }
         }
     }
-    if let Some(update) = update {
+    let update = update.ok_or_else(|| bad_request("You should set the 'update' parameter"))?;
     evaluate_sparql_update(
         store,
         update,
@@ -694,9 +680,6 @@ fn configure_and_evaluate_sparql_update(
         named_graph_uris,
         request,
     )
-    } else {
-        Err(bad_request("You should set the 'update' parameter"))
-    }
 }
 
 fn evaluate_sparql_update(