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 Results::file() function facilitates file downloads by sending files to clients. This function requires the file name and an opened file stream.

Using Results::file()

Here is an example showing how to set up a route for file downloads:

use volga::{App, Results};
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?;
        
        Results::file(file_name, file).await
    });

    app.run().await
}

Simplifying with the file! macro

Volga also offers the file! macro to streamline the process. 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 = "0.4.5", 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 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 {
        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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