Refractor to use UserRef.

src/guards/channel.rs

@@ -1,6 +1,8 @@
-use bson::{bson, doc, from_bson};
+use bson::{bson, doc, from_bson, Document};
+use mongodb::options::FindOneOptions;
 use rocket::http::RawStr;
 use rocket::request::FromParam;
+use serde::{Deserialize, Serialize};
 
 use crate::database;
 
@@ -24,6 +26,56 @@ impl<'r> FromParam<'r> for Channel {
     }
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub struct ChannelRef {
+    #[serde(rename = "_id")]
+    pub id: String,
+    #[serde(rename = "type")]
+    pub channel_type: u8,
+
+    // information required for permission calculations
+    pub recipients: Option<Vec<String>>,
+    pub guild: Option<String>,
+}
+
+impl ChannelRef {
+    pub fn fetch_data(&self, projection: Document) -> Option<Document> {
+        database::get_collection("channels")
+            .find_one(
+                doc! { "_id": &self.id },
+                FindOneOptions::builder().projection(projection).build(),
+            )
+            .expect("Failed to fetch channel from database.")
+    }
+}
+
+impl<'r> FromParam<'r> for ChannelRef {
+    type Error = &'r RawStr;
+
+    fn from_param(param: &'r RawStr) -> Result<Self, Self::Error> {
+        let id = param.to_string();
+        let result = database::get_collection("channels")
+            .find_one(
+                doc! { "_id": id },
+                FindOneOptions::builder()
+                    .projection(doc! {
+                        "_id": 1,
+                        "type": 1,
+                        "recipients": 1,
+                        "guild": 1,
+                    })
+                    .build(),
+            )
+            .unwrap();
+
+        if let Some(channel) = result {
+            Ok(from_bson(bson::Bson::Document(channel)).expect("Failed to deserialize channel."))
+        } else {
+            Err(param)
+        }
+    }
+}
+
 impl<'r> FromParam<'r> for Message {
     type Error = &'r RawStr;