Use the `multipart` crate to parse incoming multipart/form-data requests and extract files in your Axum or Actix-web handler. Add the dependency to `Cargo.toml` and implement a handler that consumes the stream to save the file.

How to Handle File Uploads in Rust Web Applications

Use the multipart crate to parse incoming multipart/form-data requests and extract files in your Axum or Actix-web handler. Add the dependency to Cargo.toml and implement a handler that consumes the stream to save the file.

use axum::{extract::Multipart, response::IntoResponse, routing::post, Router};
use std::io::Write;

#[tokio::main]
async fn main() {
    let app = Router::new().route("/upload", post(upload));
    let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.unwrap();
    axum::serve(listener, app).await.unwrap();
}

async fn upload(mut multipart: Multipart) -> impl IntoResponse {
    while let Some(field) = multipart.next_field().await.unwrap() {
        let mut file = std::fs::File::create("uploaded.txt").unwrap();
        while let Some(chunk) = field.chunk().await.unwrap() {
            file.write_all(&chunk).unwrap();
        }
    }
    "File uploaded"
}

Handling file uploads in Rust web applications lets your server accept files sent from a browser, like images or documents. It works by breaking the incoming data into chunks, reading them one by one, and writing them to your server's disk. Think of it like a mailroom clerk taking a large package, opening it, and placing the contents on a shelf.