refactor: remove dependency on async-trait

linkup/Cargo.toml

@@ -4,7 +4,6 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-async-trait = "0.1.68"
 getrandom = { version = "0.2.8", features = ["js"] }
 hex = "0.4"
 rand = "0.8"

linkup/src/lib.rs

@@ -4,7 +4,8 @@ mod name_gen;
 mod session;
 mod session_allocator;
 
-use async_trait::async_trait;
+use std::future::Future;
+
 use rand::Rng;
 use thiserror::Error;
 
@@ -28,11 +29,13 @@ pub enum SessionError {
     ConfigErr(String),
 }
 
-#[async_trait(?Send)]
+// Since this trait is theoretically public (even though, the idea is for it to be used by the other modules within
+// this workspace), we should return `impl Future` instead of having `async fn` so that we can add and ensure
+// any desired bounds.
 pub trait StringStore {
-    async fn get(&self, key: String) -> Result<Option<String>, SessionError>;
-    async fn exists(&self, key: String) -> Result<bool, SessionError>;
-    async fn put(&self, key: String, value: String) -> Result<(), SessionError>;
+    fn get(&self, key: String) -> impl Future<Output = Result<Option<String>, SessionError>>;
+    fn exists(&self, key: String) -> impl Future<Output = Result<bool, SessionError>>;
+    fn put(&self, key: String, value: String) -> impl Future<Output = Result<(), SessionError>>;
 }
 
 #[derive(PartialEq)]

linkup/src/memory_session_store.rs

@@ -1,7 +1,5 @@
 use std::{collections::HashMap, sync::RwLock};
 
-use async_trait::async_trait;
-
 use crate::{SessionError, StringStore};
 
 pub struct MemoryStringStore {
@@ -22,7 +20,6 @@ impl Default for MemoryStringStore {
     }
 }
 
-#[async_trait(?Send)]
 impl StringStore for MemoryStringStore {
     async fn get(&self, key: String) -> Result<Option<String>, SessionError> {
         match self.store.read() {

linkup/src/session_allocator.rs

@@ -4,12 +4,12 @@ use crate::{
     StringStore,
 };
 
-pub struct SessionAllocator<'a> {
-    store: &'a dyn StringStore,
+pub struct SessionAllocator<'a, S: StringStore> {
+    store: &'a S,
 }
 
-impl<'a> SessionAllocator<'a> {
-    pub fn new(store: &'a dyn StringStore) -> Self {
+impl<'a, S: StringStore> SessionAllocator<'a, S> {
+    pub fn new(store: &'a S) -> Self {
         Self { store }
     }
 

worker/src/kv_store.rs

@@ -1,5 +1,5 @@
 use linkup::{SessionError, StringStore};
-use worker::{async_trait::async_trait, kv::KvStore};
+use worker::kv::KvStore;
 
 pub struct CfWorkerStringStore {
     kv: KvStore,
@@ -11,7 +11,6 @@ impl CfWorkerStringStore {
     }
 }
 
-#[async_trait(?Send)]
 impl StringStore for CfWorkerStringStore {
     async fn get(&self, key: String) -> Result<Option<String>, SessionError> {
         match self.kv.get(key.as_str()).text().await {

worker/src/lib.rs

@@ -10,9 +10,9 @@ mod kv_store;
 mod utils;
 mod ws;
 
-async fn linkup_session_handler<'a>(
+async fn linkup_session_handler<'a, S: StringStore>(
     mut req: Request,
-    sessions: &'a SessionAllocator<'a>,
+    sessions: &'a SessionAllocator<'a, S>,
 ) -> Result<Response> {
     let body_bytes = match req.bytes().await {
         Ok(bytes) => bytes,
@@ -39,9 +39,9 @@ async fn linkup_session_handler<'a>(
     }
 }
 
-async fn linkup_preview_handler<'a>(
+async fn linkup_preview_handler<'a, S: StringStore>(
     mut req: Request,
-    sessions: &'a SessionAllocator<'a>,
+    sessions: &'a SessionAllocator<'a, S>,
 ) -> Result<Response> {
     let body_bytes = match req.bytes().await {
         Ok(bytes) => bytes,
@@ -110,9 +110,9 @@ async fn set_cached_req(
     Ok(resp)
 }
 
-async fn linkup_request_handler<'a>(
+async fn linkup_request_handler<'a, S: StringStore>(
     mut req: Request,
-    sessions: &'a SessionAllocator<'a>,
+    sessions: &'a SessionAllocator<'a, S>,
 ) -> Result<Response> {
     let url = match req.url() {
         Ok(url) => url.to_string(),

worker/src/ws.rs

@@ -8,9 +8,9 @@ use futures::{
 
 use crate::http_util::plaintext_error;
 
-pub async fn linkup_ws_handler<'a>(
+pub async fn linkup_ws_handler<'a, S: StringStore>(
     req: Request,
-    sessions: &'a SessionAllocator<'a>,
+    sessions: &'a SessionAllocator<'a, S>,
 ) -> Result<Response> {
     let url = match req.url() {
         Ok(url) => url.to_string(),