Improved error handling in GetUser state handler

src/state/get_user.rs

@@ -1,7 +1,7 @@
 use crate::prelude::*;
 use futures::TryFutureExt;
 use itertools::Itertools;
-use std::{fmt::Write, path::Path};
+use std::{borrow::Cow, fmt::Write, path::Path};
 use teloxide::{
     net::Download,
     types::{Document, FileMeta},
@@ -128,7 +128,38 @@ fn user_from_vec(
     }
 }
 
+#[inline]
+async fn user_from_document(
+    bot: &Throttle<Bot>,
+    db: &Pool,
+    document: Option<&Document>,
+    user_id: u64,
+) -> Result<User, Cow<'static, str>> {
+    let (data, existing_names) = {
+        let file = match validate_document(document) {
+            Ok(document) => &document.file,
+            Err(text) => return Err(Cow::Borrowed(text)),
+        };
+
+        let data =
+            download_file(bot, file).map_err(|_| "Error getting existing account names. Try again");
+
+        let existing_names = Account::get_names(user_id, db)
+            .try_collect()
+            .map_err(|_| "Error downloading the file. Try again");
+
+        try_join!(data, existing_names)?
+    };
+
+    match spawn_blocking(|| user_from_vec(data, existing_names)).await {
+        Ok(Ok(Ok(user))) => Ok(user),
+        Ok(Ok(Err(error_text))) => Err(Cow::Owned(error_text)),
+        _ => Err(Cow::Borrowed("Error parsing the json file. Try again")),
+    }
+}
+
 /// Function to handle `GetUser` state. It doesn't actually validate anything
+#[inline]
 pub async fn get_user(
     bot: Throttle<Bot>,
     msg: Message,
@@ -153,39 +184,15 @@ pub async fn get_user(
         return Ok(());
     }
 
-    let file = match validate_document(msg.document()) {
-        Ok(document) => &document.file,
-        Err(text) => {
-            handler
-                .previous
-                .alter_message(&bot, text, None, None)
-                .await?;
-            return Ok(());
-        }
-    };
-
-    let existing_names = Account::get_names(user_id, &db)
-        .try_collect()
-        .map_err(Into::into);
-
-    let (data, existing_names) = try_join!(download_file(&bot, file), existing_names)?;
-
-    let user = match spawn_blocking(move || user_from_vec(data, existing_names)).await? {
-        Ok(Ok(user)) => user,
-        Ok(Err(error_text)) => {
+    let user = match user_from_document(&bot, &db, msg.document(), user_id).await {
+        Ok(user) => user,
+        Err(error_text) => {
             handler
                 .previous
                 .alter_message(&bot, error_text, None, None)
                 .await?;
             return Ok(());
         }
-        Err(_) => {
-            handler
-                .previous
-                .alter_message(&bot, "Error parsing the json file. Try again", None, None)
-                .await?;
-            return Ok(());
-        }
     };
 
     let previous = handler.previous;