sfdown
SourceForge project downloader. Will clone the project's directory tree and fetch all files.
Supports concurrency, integrity verification, file deduplication and resuming interrupted downloads.
Installation
gem install sfdown
Usage
Run with:
sfdown project_name [-lmn] [-c concurrent] [-i input] [-o output] [-t timeout] [-s sleep]
Arguments:
| Arguments | Default | Description |
|---|---|---|
-c or --concurrent |
4 | Number of parallel network workers, used in both stages |
-i or --input |
None | Bootstrap the download directly from a metadata JSON file |
-l or --link |
False | Hard-link duplicate files instead of copying them |
-m or --metadata |
False | Save metadata as JSON to disk at project's root |
-n or --no |
False | Only fetch directory tree structure and file metadata, not files |
-o or --output |
Current dir | Path to store project's root |
-t or --timeout |
5 | Timeout for each GET request |
-s or --sleep |
0 | Wait in-between requests |
Features
Integrity verification
SourceForge publishes each file's MD5 / SHA1 hash. Whenever available, this is used after downloading to verify file integrity. SHA1 is preferred for its strength, MD5 is used as a fallback. Mismatches aren't discarded, simply logged.
File deduplication
The MD5 / SHA1 hashes are also used so that files that appear more than once in a project are downloaded only once: the first copy is fetched, the rest are copied from it locally. Progress totals only count the bytes that actually need fetching.
With -l the duplicates are hard-linked instead, so they take no extra disk space at all. If the filesystem doesn't support linking, sfdown warns once and falls back to copying.
Bootstrapping downloads
The process happens in two stages:
- Stage 1 browses the directory tree and maps it out, optionally exporting the metadata to a JSON file (
-mflag). - Stage 2 creates the directory tree and fetches all files.
Stage 2 can be started directly from a preexisting metadata file exported in stage 1 (-i flag).
Concurrency and throttling
Multiple workers can be used in parallel for both stages via the -c flag.
To prevent rate-limits, an optional sleep can be added between fetches via the -s flag.
Note: -s is applied per worker, so with -c the effective request rate scales roughly linearly with the number of workers.
Resuming interrupted downloads
The download process (stage 2) can be resumed by simply running the same command again, whether the process had been bootstrapped with -i or not.
Before downloading anything, sfdown checks each file's local path and verifies any existing copy against its published MD5 / SHA1 hash. Files that match are kept and skipped; anything missing, corrupt, or unverifiable (no checksum) is re-downloaded.