Fix object download to file

[jeasai]

What

Fixed minio::s3::builders::object_content::ObjectContent::to_file() (which tries to write in a file opened in read-only mode), and added an example to show how to use it.

To reproduce the issue

main.rs:

use minio::s3::args::{BucketExistsArgs, MakeBucketArgs};
use minio::s3::builders::ObjectContent;
use minio::s3::client::ClientBuilder;
use minio::s3::creds::StaticProvider;
use minio::s3::http::BaseUrl;
use minio::s3::types::S3Api;
use std::path::Path;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
    let base_url = "https://play.min.io".parse::<BaseUrl>()?;

    let static_provider = StaticProvider::new(
        "Q3AM3UQ867SPQQA43P2F",
        "zuf+tfteSlswRu7BJ86wekitnifILbZam1KYY3TG",
        None,
    );

    let client = ClientBuilder::new(base_url.clone())
        .provider(Some(Box::new(static_provider)))
        .build()?;

    let bucket_name: &str = "asiatrip";
    let object_name: &str = "asiaphotos-2015.zip";
    let download_path: &str = &format!("/tmp/downloads/{object_name}");

    // Creates the bucket if it doesn't exist

    let exists = client.bucket_exists(&BucketExistsArgs::new(&bucket_name).unwrap()).await?;
    if !exists {
        client.make_bucket(&MakeBucketArgs::new(&bucket_name).unwrap()).await.unwrap();
    }

    // Adds an object in the bucket

    let content = ObjectContent::from(vec![]);
    client.put_object_content(bucket_name, object_name, content).send().await?;

    // Downloads the object to a file

    let get_object = client.get_object(bucket_name, object_name).send().await?;

    if let Err(e) = get_object.content.to_file(&Path::new(download_path)).await {
        println!("ObjectContent::to_file() failed: {e}");
    }

    Ok(())
}

Cargo.toml:

[package]
name = "sample"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
minio = { git="https://github.com/minio/minio-rs.git", rev="c28f576cb8f8cf47fb941bb9db62b2cbd6f080c1" }
tokio = "1.41.1"

Returns:

ObjectContent::to_file() failed: No such file or directory (os error 2)

[HJLebbink]

@jeasai Thank you for providing this fix.

I’ve taken the liberty of rebasing and updating the example to make it runnable without needing to place files in specific positions. I’ve committed the changes here: a7704fe. You can either rebase from my commit, and I’ll review your PR, or I can create a new PR (with you as the co-author) for my colleague to review. Let me know what works best for you!

[jeasai]

Hello @HJLebbink !

Thanks for your answer and the example update.
I just rebased from your commit and squashed it into mine. The example runs well on my machine.
Let me know if there is anything you'd like me to update.

[HJLebbink]

LGTM

[HJLebbink]

LGTM