The download mechanism on new HappyMod
New HappyMod uses a relatively straightforward delivery setup. Files are grouped by size: large files are over 512 MB, while small files are under 512 MB. Files are also classified as popular or less popular.
Popular files are stored on Cloudflare R2 regardless of file size. The service uses different R2 locations for different regions, so downloads can be served from a location intended to improve regional speeds.
For less popular files, a user's first download in a region comes directly from the server. After a successful download, the file is available through that region's CDN cache, allowing later local users to download it from the CDN.
The download mechanism on old HappyMod
Old HappyMod also classifies files by size and popularity, but its delivery flow is more involved. Popular files are not stored on R2; instead, they are distributed as torrents, and the user downloads the torrent payload.
Some large files are split into smaller parts and stored on a CDN, particularly as an alternative when users have trouble downloading the torrent. The app must download all parts and combine them to produce the final APK.
If one or more parts fail to download, the APK may not be assembled correctly and may not install. This can make recovery more difficult than downloading one complete file.
Pros and cons of the different download mechanisms
- New HappyMod and large files: Large files are generally delivered as complete files, making it more likely that users receive a ready-to-install download.
- New HappyMod and popular files: R2 locations are limited, so some users may be served from a location farther away, which can reduce download speed.
- Old HappyMod torrents: Torrent downloads rely on enough active peers. When fewer users are sharing a file, downloads may become slower or less stable.
- Old HappyMod split files: If a large-file part is missing or incomplete, the app may be unable to assemble an installable APK.
- Both apps: Both use CDN technology in their delivery flows, which can help keep overall download speeds high.