Show specific error for oversized content

src/main.rs

 mod schema;
 mod snippet;
 
+use crate::routes::static_rocket_catch_info_for_bad_request;
 use crate::routes::static_rocket_route_info_for_create_snippet;
 use crate::routes::static_rocket_route_info_for_index;
 use crate::routes::static_rocket_route_info_for_show_snippet;
         .attach(Template::fairing())
         .manage(connection::init_pool())
         .mount("/", routes![index, show_snippet, create_snippet])
+        .register(catchers![bad_request])
         .launch();
 }

src/routes.rs

 use diesel::result::Error;
 use rocket::http::Status;
+use rocket::request::Request;
 use rocket::response::status;
 use rocket_contrib::json::Json;
 use rocket_contrib::templates::Template;
         .map(|snippet| status::Created(String::from(""), Some(Json(snippet))))
         .map_err(error_response)
 }
+
+#[catch(400)]
+pub fn bad_request(req: &Request) -> String {
+    req.headers().get_one("content-length").map_or(
+        String::from("{\"message\": \"Bad request\"}"),
+        |length| {
+            if length
+                .parse::<i32>()
+                .expect("Content length is non-numeric")
+                > 1_000_000
+            {
+                String::from("{\"message\": \"Snippet must be under 1mb\"}")
+            } else {
+                String::from("{\"message\": \"Bad request\"}")
+            }
+        },
+    )
+}