fix(dashproof-lab): clear error when crypto.subtle is unavailable

[thephez]

Summary

• Loading the app over plain http:// (e.g. bare-IP hosting, non-HTTPS IPFS gateways) crashed with Cannot read properties of undefined (reading 'digest') because crypto.subtle is only exposed in Secure Contexts.
• hashFile now checks for crypto.subtle up front and throws a clear message pointing the user to HTTPS or http://localhost. Applied to both the React app (src/lib/hash.ts) and the zero-build companion (public/dashproof-lite.html).
• Existing callers in AnchorForm and VerifyPanel already pipe thrown errors through errorMessage(err) into the status UI, so the new message surfaces inline instead of crashing.
• Added a regression test that stubs crypto.subtle = undefined and asserts the exact error string, so any future reword fails the test rather than silently degrading the diagnostic.

Test plan

• npm run test — 138/138 pass (20 files)
• npm run format — clean
• npm run build — typecheck + bundle clean
• Manually load the built app over http:// and confirm the inline error replaces the cryptic crash
• Manually load over https:// / http://localhost and confirm hashing still works

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes

  • Improved error handling for non-secure contexts. Users now receive clear instructions to use HTTPS or http://localhost instead of encountering cryptic failures during file operations.

• Tests

  • Added regression test for secure context validation.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: de2f587b-c0e9-40db-bb81-40f101a8d943

📥 Commits

Reviewing files that changed from the base of the PR and between 26e631e and 87322ce.

📒 Files selected for processing (3)

• example-apps/dashproof-lab/public/dashproof-lite.html
• example-apps/dashproof-lab/src/lib/hash.ts
• example-apps/dashproof-lab/test/hashFile.test.ts

---

📝 Walkthrough

Walkthrough

This PR adds an early precondition check to hashFile() ensuring crypto.subtle is available before attempting SHA-256 hashing. When unavailable (non-secure contexts), it throws a clear error guiding users to use HTTPS or http://localhost instead of failing silently during computation.

Changes

Secure Context Check for Hash Operations

Layer / File(s)	Summary
Secure context guard in hashFile src/lib/hash.ts, public/dashproof-lite.html	Both the HTML inline and TypeScript versions of hashFile now validate that crypto.subtle is available before proceeding with SHA-256 hashing, throwing a descriptive error with guidance about HTTPS or localhost when the check fails.
Test setup and regression test for secure context test/hashFile.test.ts	Test suite adds an afterEach hook to preserve and restore globalThis.crypto.subtle across tests, preventing cross-test mutation, and includes a new regression test verifying hashFile rejects with a specific Secure Context error message when crypto.subtle is undefined.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 A check before the hash begins its way,

Ensures the crypto context lights the day,

No silent fails in insecure land,

Just clear guidance—HTTPS hand in hand! 🔐

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and directly describes the main fix: adding error handling for when crypto.subtle is unavailable in non-secure contexts.
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.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/dashproof-secure-context-error

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}