Refactoring/cleanup of backend

back_end/Cargo.lock

@@ -134,27 +134,11 @@ name = "four_line_dropper_backend"
 version = "0.1.0"
 dependencies = [
  "bytes",
- "futures",
  "serde_json",
  "tokio",
  "warp",
 ]
 
-[[package]]
-name = "futures"
-version = "0.3.21"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f73fe65f54d1e12b726f517d3e2135ca3125a437b6d998caf1962961f7172d9e"
-dependencies = [
- "futures-channel",
- "futures-core",
- "futures-executor",
- "futures-io",
- "futures-sink",
- "futures-task",
- "futures-util",
-]
-
 [[package]]
 name = "futures-channel"
 version = "0.3.21"
@@ -171,34 +155,6 @@ version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0c09fd04b7e4073ac7156a9539b57a484a8ea920f79c7c675d05d289ab6110d3"
 
-[[package]]
-name = "futures-executor"
-version = "0.3.21"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9420b90cfa29e327d0429f19be13e7ddb68fa1cccb09d65e5706b8c7a749b8a6"
-dependencies = [
- "futures-core",
- "futures-task",
- "futures-util",
-]
-
-[[package]]
-name = "futures-io"
-version = "0.3.21"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fc4045962a5a5e935ee2fdedaa4e08284547402885ab326734432bed5d12966b"
-
-[[package]]
-name = "futures-macro"
-version = "0.3.21"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "33c1e13800337f4d4d7a316bf45a567dbcb6ffe087f16424852d97e97a91f512"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
-]
-
 [[package]]
 name = "futures-sink"
 version = "0.3.21"
@@ -217,13 +173,9 @@ version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d8b7abd5d659d9b90c8cba917f6ec750a74e2dc23902ef9cd4cc8c8b22e6036a"
 dependencies = [
- "futures-channel",
  "futures-core",
- "futures-io",
- "futures-macro",
  "futures-sink",
  "futures-task",
- "memchr",
  "pin-project-lite",
  "pin-utils",
  "slab",

back_end/Cargo.toml

@@ -10,4 +10,3 @@ tokio = { version = "1", features = ["full"] }
 warp = "0.3"
 serde_json = "1.0"
 bytes = "1.1"
-futures = "0.3.21"

back_end/src/main.rs

@@ -1,7 +1,6 @@
 mod json_handlers;
 
-use warp::Filter;
+use warp::{Filter, Rejection};
-use warp::Rejection;
 
 #[tokio::main]
 async fn main() {