Working with Files

Volga provides robust functionality for handling file operations such as downloading and uploading files within your Web Applications.

Downloading Files

Volga's file! macro facilitates file downloads by sending files to clients. This function requires the file name and an opened file stream.

Using the file! macro

The file! macro provides a short syntax for initiating file downloads:

use volga::{App, file};
use tokio::fs::File;

#[tokio::main]
async fn main() -> std::io::Result<()> {
    let mut app = App::new();

    // GET /download
    app.map_get("/download", || async {
        let file_name = "path/to/example.txt";
        let file = File::open(file_name).await?;
        
        file!(file_name, file)
    });

    app.run().await
}

You can check out the full example of file downloading here.

Uploading Files

For file uploads, Volga has save() and save_as() methods, that are part of the volga::File struct, allows you to stream the incoming file stream directly into a server-side file.

Example of File Upload

This example demonstrates how to set up a route to handle file uploads:

use volga::{App, File};

#[tokio::main]
async fn main() -> std::io::Result<()> {
    let mut app = App::new();

    // POST /upload
    app.map_post("/upload", |file: File| async move {
        file.save_as("path/to/example.txt").await // or file.save("path/to/folder").await
    });

    app.run().await
}

Here is the full example

Multipart uploading

In case, if you need to upload multiple files, you can leverage a multipart file uploading. It's a separate feature and if you're not using the full feature set it can be explicitly enabled in your Cargo.toml:

[dependencies]
volga = { version = "...", features = ["multipart"] }

Example of Multipart file uploading

This example demonstrates how to upload multiple files:

use volga::{App, Multipart};

#[tokio::main]
async fn main() -> std::io::Result<()> {
    let mut app = App::new();

    // POST /upload
    app.map_post("/upload", |files: Multipart| async move {
        // Saves all the files to the specified folder
        files.save_all("path/to/folder").await
    });

    app.run().await
}

If you need more control or do some job per each file you can use the next_field() method:

use std::path::Path;
use volga::{App, Multipart, ok};

#[tokio::main]
async fn main() -> std::io::Result<()> {
    let mut app = App::new();

    // POST /upload
    app.map_post("/upload", |files: Multipart| async move {
        let path = Path::new("path/to/folder");
        while let Some(field) = files.next_field().await? {
            // do something...

            field.save(path).await?;
        }
        ok!("Files have been uploaded!")
    });

    app.run().await
}

More robust examples you can find here

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