ngdp-cdn

CDN client for downloading NGDP (Next Generation Distribution Pipeline) content from Blizzard's CDN servers.

Features

🚀 Async/await - Built on Tokio for high-performance async I/O
🔄 Automatic retry - Configurable exponential backoff with jitter
🏊 Connection pooling - Efficient reuse of connections for multiple downloads
🗜️ Compression support - Automatic gzip/deflate decompression
⚡ Concurrent downloads - Download multiple files in parallel
🛡️ Error handling - Comprehensive error types for CDN operations
⏱️ Configurable timeouts - Separate connection and request timeouts

Usage

Add this to your Cargo.toml:

[dependencies]
ngdp-cdn = "0.1"

Basic Example

use ngdp_cdn::CdnClient;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create a CDN client
    let client = CdnClient::new()?;

    // Download content by hash
    let response = client.download(
        "blzddist1-a.akamaihd.net",
        "tpr/wow",
        "2e9c1e3b5f5a0c9d9e8f1234567890ab",
    ).await?;

    let content = response.bytes().await?;
    println!("Downloaded {} bytes", content.len());

    Ok(())
}

Advanced Configuration

use ngdp_cdn::CdnClient;

let client = CdnClient::builder()
    .max_retries(5)
    .initial_backoff_ms(200)
    .max_backoff_ms(30_000)
    .connect_timeout(60)
    .request_timeout(300)
    .pool_max_idle_per_host(50)
    .build()?;

CDN URL Structure

NGDP CDN URLs follow a specific pattern for content addressing:

http://{cdn_host}/{path}/{hash[0:2]}/{hash[2:4]}/{hash}

For example:

Hash: 2e9c1e3b5f5a0c9d9e8f1234567890ab
CDN Host: blzddist1-a.akamaihd.net
Path: tpr/wow
Results in: http://blzddist1-a.akamaihd.net/tpr/wow/2e/9c/2e9c1e3b5f5a0c9d9e8f1234567890ab

Error Handling

The crate provides specific error types for CDN operations:

use ngdp_cdn::Error;

match client.download(host, path, hash).await {
    Ok(response) => {
        // Process response
    }
    Err(Error::ContentNotFound { hash }) => {
        println!("Content {} not found on CDN", hash);
    }
    Err(Error::RateLimited { retry_after_secs }) => {
        println!("Rate limited, retry after {} seconds", retry_after_secs);
    }
    Err(e) => {
        println!("Other error: {}", e);
    }
}

Integration with NGDP

This crate is designed to work with other NGDP components:

Use ribbit-client to get CDN configuration
Use tact-client to get content manifests
Use ngdp-cdn to download the actual content

// Example workflow (simplified)
let ribbit = ribbit_client::RibbitClient::new(Region::US);
let cdns = ribbit.get_product_cdns("wow").await?;

let tact = tact_client::HttpClient::new(Region::US)?;
let versions = tact.get_versions_parsed("wow").await?;

let cdn_client = ngdp_cdn::CdnClient::new()?;
for host in cdns.hosts {
    if let Ok(content) = cdn_client.download(&host, &cdns.path, &content_hash).await {
        // Successfully downloaded from this CDN
        break;
    }
}

Performance Considerations

Connection pooling: The client maintains a pool of connections to each host
Concurrent downloads: Use multiple client instances or clone the client for parallel downloads
Retry strategy: Configure retry parameters based on your network conditions
Timeouts: Adjust timeouts based on file sizes and network speed

📄 License

This project is dual-licensed under either:

Apache License, Version 2.0 (LICENSE-APACHE)
MIT license (LICENSE-MIT)

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

🫶 Acknowledgments

This crate is part of the cascette-rs project, providing tools for World of Warcraft emulation development.

ngdp-cdn 0.1.1