aradotso/github-sandbox-file-downloader

GitHub Sandbox File Downloader

Skill by ara.so — Daily 2026 Skills collection.

A GitHub Actions-based tool that lets you download files into your repository simply by writing a specially formatted commit message — no CLI, no tokens, no secrets required.

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What It Does

github-sandbox listens for commit messages containing download: or download-zip: commands. When detected, a GitHub Actions workflow runs and:

• download: — Fetches each URL and saves files individually to downloads/ using their original filenames.
• download-zip: — Fetches all URLs and bundles them into a single timestamped .zip archive in downloads/.

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Setup

1. Fork the Repository

Fork maanimis/github-sandbox into your GitHub account.

2. Enable Read/Write Workflow Permissions

1. Go to your forked repo on GitHub
2. Navigate to Settings → Actions → General
3. Scroll to Workflow permissions
4. Select Read and write permissions
5. Click Save

No API keys, tokens, or secrets are needed.

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Usage

Trigger downloads by committing to your repo with a specially formatted commit message.

Via GitHub Web UI

1. Open any file (e.g., README.md) in your repo
2. Click the pencil icon (✏️) to edit
3. Make any minor change (a space, blank line, etc.)
4. In the Commit changes box, type your download command
5. Select Commit directly to the main branch
6. Click Commit changes

Via Git CLI

# Download individual files
git commit --allow-empty -m "download: https://example.com/file.zip"

# Download multiple files
git commit --allow-empty -m "download: https://example.com/a.zip https://example.com/b.pdf"

# Download and bundle into a ZIP archive
git commit --allow-empty -m "download-zip: https://example.com/a.zip https://example.com/b.pdf"

git push origin main

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Command Reference

download: — Save Files Individually

download: URL1 URL2 URL3

Examples:

# Single file
git commit --allow-empty -m "download: https://example.com/dataset.csv"

# Multiple files
git commit --allow-empty -m "download: https://example.com/model.bin https://example.com/config.json https://example.com/vocab.txt"

Output: Files saved individually to downloads/ with original filenames:

downloads/
  dataset.csv
  model.bin
  config.json
  vocab.txt

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download-zip: — Bundle Into ZIP Archive

download-zip: URL1 URL2 URL3

Examples:

# Single file zipped
git commit --allow-empty -m "download-zip: https://example.com/report.pdf"

# Multiple files bundled
git commit --allow-empty -m "download-zip: https://example.com/a.zip https://example.com/b.pdf https://example.com/c.csv"

Output: A single timestamped archive in downloads/:

downloads/
  archive_20260423_153012.zip

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Command Summary Table

| Command | URLs | Output | |---|---|---| | download: URL | Single | downloads/filename.ext | | download: URL1 URL2 | Multiple | downloads/file1.ext, downloads/file2.ext | | download-zip: URL | Single | downloads/archive_YYYYMMDD_HHMMSS.zip | | download-zip: URL1 URL2 | Multiple | downloads/archive_YYYYMMDD_HHMMSS.zip (all bundled) |

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How the Workflow Works

The GitHub Actions workflow (.github/workflows/download.yml) operates as follows:

# Conceptual workflow structure
on:
  push:
    branches: [main]

jobs:
  download:
    runs-on: ubuntu-latest
    steps:
      - name: Check commit message for download command
        # Parses commit message for "download:" or "download-zip:"
        # Extracts URLs from the message
        # Downloads files using curl/wget
        # Commits results to downloads/ with [skip ci] to prevent loops

Key design details:

• The workflow uses [skip ci] in its own commit message to avoid infinite trigger loops.
• If no download: or download-zip: command is found, the workflow exits without doing anything.
• All output files are committed back to the downloads/ directory automatically.

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Checking Download Results

1. Click the Actions tab in your repository
2. Click the latest workflow run to monitor progress and view logs
3. After completion, go to the Code tab and open downloads/ to find your files

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Common Patterns

Downloading a Dataset

git commit --allow-empty -m "download: https://raw.githubusercontent.com/datasets/covid-19/main/data/worldwide-aggregated.csv"
git push origin main

Downloading Multiple Assets and Archiving

git commit --allow-empty -m "download-zip: https://example.com/weights.bin https://example.com/tokenizer.json https://example.com/config.yaml"
git push origin main

Downloading a Public GitHub Release Asset

git commit --allow-empty -m "download: https://github.com/owner/repo/releases/download/v1.0.0/binary-linux-amd64.tar.gz"
git push origin main

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Troubleshooting

Workflow doesn't trigger

• Confirm Read and write permissions are enabled under Settings → Actions → General → Workflow permissions.
• Make sure you committed directly to the main branch (not a PR or other branch, unless the workflow is configured otherwise).
• Check the Actions tab for any failed or skipped runs.

Files not appearing in downloads/

• Verify the URLs are publicly accessible — no authentication, login, or VPN required.
• Check workflow logs in the Actions tab for HTTP errors (403, 404, etc.).
• Ensure URLs don't redirect to a login page.

Workflow runs in an infinite loop

• This shouldn't happen — the workflow appends [skip ci] to its own commit messages.
• If you've modified the workflow file, verify the [skip ci] tag is still present in the auto-commit step.

Multiple URLs not downloading

• Ensure URLs are separated by spaces only (no commas).
• Avoid special characters in the commit message that might break shell parsing.

# ✅ Correct
git commit --allow-empty -m "download: https://example.com/a.zip https://example.com/b.zip"

# ❌ Incorrect (comma separator)
git commit --allow-empty -m "download: https://example.com/a.zip, https://example.com/b.zip"

Commit message not recognized

• The command prefix must be exactly download: or download-zip: (lowercase, with colon, followed by a space).
• The command must appear in the commit message subject line (first line), not the body.

# ✅ Correct
git commit --allow-empty -m "download: https://example.com/file.zip"

# ❌ Won't trigger (wrong prefix)
git commit --allow-empty -m "Download: https://example.com/file.zip"

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Notes & Limitations

• Public URLs only — downloads require no authentication.
• GitHub Actions limits apply — workflow execution time, storage, and API rate limits are subject to your GitHub plan.
• Branch — by default, the workflow triggers on pushes to main. Check .github/workflows/ if your default branch differs.
• File size — very large files may hit GitHub repository size limits (typically 100MB per file, 1GB total soft limit).