fix: impersonate Chrome for Bandcamp downloads

[D3SOX]

Summary

• pass --impersonate chrome to Bandcamp track downloads
• use the same impersonation arguments when resolving Bandcamp album metadata
• document the workaround for yt-dlp issue #17356

Why

Bandcamp may return a client-challenge page to yt-dlp instead of track or album metadata. Chrome impersonation works around that response so Bandcamp downloads can proceed.

Validation

• bun test src/ytdlp.test.ts
• bun run lint

Summary by CodeRabbit

• Bug Fixes

  • Improved Bandcamp URL handling for metadata lookups and audio downloads.
  • Enhanced compatibility with sites requiring Chrome-like browser identification.
  • Preserved existing SoundCloud format selection, cookie handling, progress reporting, and output processing.

• Documentation

  • Updated prerequisites with installation guidance for the optional curl_cffi backend required for Bandcamp support.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 75eee7cb-3c5d-412f-b244-34202f0df40f

📥 Commits

Reviewing files that changed from the base of the PR and between a8b8837 and 5800e3c.

📒 Files selected for processing (1)

• README.md

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📝 Walkthrough

Walkthrough

The yt-dlp integration detects Bandcamp URLs and applies Chrome impersonation arguments to audio download and album metadata commands. The README documents the optional curl_cffi backend required for Bandcamp support.

Changes

Bandcamp yt-dlp support

Layer / File(s)	Summary
Bandcamp detection and command arguments src/ytdlp.ts	The module imports isBandcampUrl and defines Chrome impersonation arguments for Bandcamp requests.
Bandcamp metadata, download, and setup documentation src/ytdlp.ts, README.md	Bandcamp download and album metadata commands prepend the impersonation arguments. SoundCloud-specific format selection remains unchanged. The prerequisites document curl_cffi installation options.ため

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• D3SOX/sc-gate-dl#87: Extends the same yt-dlp invocation logic in src/ytdlp.ts.
• D3SOX/sc-gate-dl#89: Modifies src/ytdlp.ts for yt-dlp and Bandcamp/SoundCloud handling.
• D3SOX/sc-gate-dl#90: Adds related Bandcamp handling in src/ytdlp.ts.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: using Chrome impersonation for Bandcamp downloads.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix-bandcamp-impersonation

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/ytdlp.ts`:
- Around line 34-35: Ensure the yt-dlp installation used by the project provides
Chrome impersonation support, including the optional curl-cffi backend required
by BANDCAMP_IMPERSONATION_ARGS. Pin a compatible yt-dlp/curl-cffi setup or add a
capability check that detects unavailable support and handles it before Bandcamp
metadata or download commands run.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 05fd2ba7-3b79-471c-b150-d5b904a40559

📥 Commits

Reviewing files that changed from the base of the PR and between b32599f and a8b8837.

📒 Files selected for processing (1)

• src/ytdlp.ts