Issue with Returning JSON Response in Axum Handler (Result<Response> Expected) #1316

alokmahor · 2025-03-21T14:00:22Z

alokmahor
Mar 21, 2025

I'm working on a Rust web application using Loco-rs, Axum, and SeaORM, and I encountered an error when trying to return a JSON response from my api endpoint.

Error Message

   --> src/controllers/wallet.rs:161:5
    |
79  | pub async fn leaderboard(auth: auth::JWT, State(ctx): State<AppContext>) -> Result<Response> {
    |                                                                             ---------------- expected `std::result::Result<axum::http::Response<Body>, loco_rs::Error>` because of return type
...
161 |     format::Json(LeaderboardResponse::new(coins, diamonds, current_user_coins, current_user_diamonds))
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `Result<Response<Body>, Error>`, found `Json<...`

Code Snippet

#![allow(clippy::missing_errors_doc)]
#![allow(clippy::unnecessary_struct_initialization)]
#![allow(clippy::unused_async)]
use loco_rs::prelude::*;
use serde::{Deserialize, Serialize};
use axum::debug_handler;

use crate::models::_entities::wallets::{self, ActiveModel, Entity, Model};

use crate::{
    models::{
        _entities::{game_users, telegram_users},
    },
    views::wallets::{WalletResponse},
};

#[derive(Debug, Deserialize, Serialize)]
pub struct UserRank {
    name: String,
    rank: u32,
    balance: i32,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct LeaderboardResponse {
    coins: Vec<UserRank>,
    diamonds: Vec<UserRank>,
    current_user_coins: UserRank,
    current_user_diamonds: UserRank,
}

impl LeaderboardResponse {
    #[must_use]
    pub fn new(coins: Vec<UserRank>, diamonds: Vec<UserRank>, current_user_coins: UserRank, current_user_diamonds: UserRank) -> Self {
        Self {
            coins: coins,
            diamonds: diamonds,
            current_user_coins: current_user_coins,
            current_user_diamonds: current_user_diamonds
        }
    }
}

#[debug_handler]
pub async fn leaderboard(auth: auth::JWT, State(ctx): State<AppContext>) -> Result<Response> {
    let user_pid = auth.claims.pid;
    let db = &ctx.db;

    // Query for top 10 users based on coin balance
    let coins_query = r#"
        SELECT t.first_name, t.last_name, w.coins, 
               RANK() OVER (ORDER BY w.coins DESC) AS rank
        FROM wallets w
        JOIN game_users g ON w.game_user_id = g.id
        JOIN telegram_users t ON g.id = t.game_user_id
        ORDER BY w.coins DESC LIMIT 10;
    "#;

    let coins = db.query_all(Statement::from_string(DbBackend::MySql, coins_query)).await.unwrap()
        .into_iter().map(|row| UserRank {
            name: format!("{} {}", row.try_get::<String>("", "first_name").unwrap_or_default(),
                                 row.try_get::<String>("", "last_name").unwrap_or_default()),
            rank: row.try_get::<u32>("", "rank").unwrap_or(0),
            balance: row.try_get::<i32>("", "coins").unwrap_or(0),
        }).collect();

    // Similar query for diamonds
    let diamonds_query = r#"
        SELECT t.first_name, t.last_name, w.diamonds, 
               RANK() OVER (ORDER BY w.diamonds DESC) AS rank
        FROM wallets w
        JOIN game_users g ON w.game_user_id = g.id
        JOIN telegram_users t ON g.id = t.game_user_id
        ORDER BY w.diamonds DESC LIMIT 10;
    "#;

    let diamonds = db.query_all(Statement::from_string(DbBackend::MySql, diamonds_query)).await.unwrap()
        .into_iter().map(|row| UserRank {
            name: format!("{} {}", row.try_get::<String>("", "first_name").unwrap_or_default(),
                                 row.try_get::<String>("", "last_name").unwrap_or_default()),
            rank: row.try_get::<u32>("", "rank").unwrap_or(0),
            balance: row.try_get::<i32>("", "diamonds").unwrap_or(0),
        }).collect();

    let response = LeaderboardResponse::new(coins, diamonds, current_user_coins, current_user_diamonds);
    
    // This line throws the error
    format::Json(response)
}

How can I properly return a JSON response in Axum while maintaining the expected return type of Result<Response>? Any guidance on fixing this type mismatch would be greatly appreciated!

Answered by alokmahor

Mar 21, 2025

By changing format::Json to format::json code is working fine

View full answer

alokmahor · 2025-03-21T17:07:20Z

alokmahor
Mar 21, 2025
Author

By changing format::Json to format::json code is working fine

0 replies

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Issue with Returning JSON Response in Axum Handler (Result<Response> Expected) #1316

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Issue with Returning JSON Response in Axum Handler (Result<Response> Expected) #1316

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alokmahor Mar 21, 2025

Error Message

Code Snippet

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alokmahor Mar 21, 2025 Author

alokmahor
Mar 21, 2025

alokmahor
Mar 21, 2025
Author