Upgrade to Actix V2, bump SQLX version, code cleanup, intergrate ratelimiter (#288)

* Upgrade to Actix V2, bump SQLX version, code cleanup, intergrate ratelimiter

* Add pack file path validation

* Fix compilation error caused by incorrect merge

src/ratelimit/errors.rs

@@ -0,0 +1,45 @@
+//! Errors that can occur during middleware processing stage
+use actix_web::ResponseError;
+use log::*;
+use thiserror::Error;
+
+/// Custom error type. Useful for logging and debugging different kinds of errors.
+/// This type can be converted to Actix Error, which defaults to
+/// InternalServerError
+///
+#[derive(Debug, Error)]
+pub enum ARError {
+    /// Read/Write error on store
+    #[error("read/write operatiion failed: {0}")]
+    ReadWriteError(String),
+
+    /// Identifier error
+    #[error("client identification failed")]
+    IdentificationError,
+    /// Limited Error
+    #[error("You are being ratelimited. Please wait {reset} seconds. {remaining}/{max_requests} remaining.")]
+    LimitedError {
+        max_requests: usize,
+        remaining: usize,
+        reset: u64,
+    },
+}
+
+impl ResponseError for ARError {
+    fn error_response(&self) -> actix_web::web::HttpResponse {
+        match self {
+            Self::LimitedError {
+                max_requests,
+                remaining,
+                reset,
+            } => {
+                let mut response = actix_web::web::HttpResponse::TooManyRequests();
+                response.insert_header(("x-ratelimit-limit", max_requests.to_string()));
+                response.insert_header(("x-ratelimit-remaining", remaining.to_string()));
+                response.insert_header(("x-ratelimit-reset", reset.to_string()));
+                response.body(self.to_string())
+            }
+            _ => actix_web::web::HttpResponse::build(self.status_code()).body(self.to_string()),
+        }
+    }
+}