feat: add GatewayOptions

src/gateway/options.rs

@@ -0,0 +1,108 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#[derive(Clone, PartialEq, Eq, Ord, PartialOrd, Debug, Default)]
+/// Options passed when initializing the gateway connection.
+///
+/// E.g. compression
+///
+/// # Note
+///
+/// Discord allows specifying the api version (v10, v9, ...) as well, but chorus is built upon one
+/// main version (v9).
+///
+/// Similarly, discord also supports etf encoding, while chorus does not (yet).
+/// We are looking into supporting it as an option, since it is faster and more lightweight.
+///
+/// See <https://docs.discord.sex/topics/gateway#connections>
+pub struct GatewayOptions {
+   pub encoding: GatewayEncoding,
+   pub transport_compression: GatewayTransportCompression,
+}
+
+impl GatewayOptions {
+    /// Adds the options to an existing gateway url
+    ///
+    /// Returns the new url
+    pub(crate) fn add_to_url(&self, url: String) -> String {
+        
+        let mut url = url;
+
+        let mut parameters = Vec::with_capacity(2);
+        
+        let encoding = self.encoding.to_url_parameter();
+        parameters.push(encoding);
+
+        let compression = self.transport_compression.to_url_parameter();
+        if let Some(some_compression) = compression {
+            parameters.push(some_compression);
+        }
+
+        let already_has_parameters = url.contains("?") && url.contains("=");
+
+        for index in 0..parameters.len() {
+            if index == 0 && !already_has_parameters {
+                url = format!("{}?{}", url, parameters[index]);
+            }
+            else {
+                url = format!("{}&{}", url, parameters[index]);
+            }
+        }
+
+        url
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Debug, Default)]
+/// Possible transport compression options for the gateway.
+///
+/// See <https://docs.discord.sex/topics/gateway#transport-compression>
+pub enum GatewayTransportCompression {
+    /// Do not transport compress packets
+    None,
+    /// Transport compress using zlib stream
+    #[default]
+    ZLibStream,
+}
+
+impl GatewayTransportCompression {
+    /// Returns the option as a url parameter.
+    /// 
+    /// If set to [GatewayTransportCompression::None] returns [None].
+    ///
+    /// If set to anything else, returns a string like "compress=zlib-stream"
+    pub(crate) fn to_url_parameter(&self) -> Option<String> {
+       match self {
+            Self::None =>  None,
+            Self::ZLibStream => Some(String::from("compress=zlib-stream"))
+       } 
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Debug, Default)]
+/// See <https://docs.discord.sex/topics/gateway#encoding-and-compression>
+pub enum GatewayEncoding {
+    /// Javascript object notation, a standard for websocket connections,
+    /// but contains a lot of overhead
+    #[default]
+    Json,
+    /// A binary format originating from Erlang
+    ///
+    /// Should be lighter and faster than json.
+    ///
+    /// !! Chorus does not implement ETF yet !!
+    ETF
+}
+
+impl GatewayEncoding {
+    /// Returns the option as a url parameter.
+    /// 
+    /// Returns a string like "encoding=json"
+    pub(crate) fn to_url_parameter(&self) -> String {
+       match self {
+           Self::Json => String::from("encoding=json"),
+           Self::ETF => String::from("encoding=etf")
+       } 
+    }
+}