[MBL-19580][Student][Teacher] File download logic update

[tamaskozmer]

Test plan:

• Test all the failing scenarios for file downloads (we have the list on Slack).
• Smoke test all the media playback features

refs: MBL-19580
affects: Student, Teacher
release note: none

Checklist

• Run E2E test suite
• Tested in light mode

[claude]

Summary

This PR removes the RouteUtils.getMediaUri() method and its associated async media URL resolution logic, simplifying media handling by using URLs directly instead of making HEAD requests to resolve redirects and detect DASH content types.

Positive Changes

✅ Significant complexity reduction - Removes unnecessary async/coroutine wrappers and HEAD requests for every media URL
✅ Better performance - Eliminates network round-trips before playing media
✅ Cleaner architecture - Removes the complex redirect following logic from RouteUtils
✅ Smart fallback handling - Adds .mpd retry logic in ExoPlayerHelper for DASH videos without proper extensions

Issues Found

• Thread safety concerns in OpenMediaAsyncTaskLoader - Instance variables are modified during async operations (libs/pandautils/src/main/java/com/instructure/pandautils/loaders/OpenMediaAsyncTaskLoader.kt:301)
• Null pointer risk - Non-null assertion on response body without null check (libs/pandautils/src/main/java/com/instructure/pandautils/loaders/OpenMediaAsyncTaskLoader.kt:341)
• State management issue in ExoPlayerHelper - currentUri is permanently modified during retry attempts (libs/pandautils/src/main/java/com/instructure/pandautils/utils/ExoPlayerHelper.kt:191)
• Potential regression in URL handling - Direct string comparison may fail with query parameters (apps/student/src/main/java/com/instructure/student/activity/BaseRouterActivity.kt:319)
• Cache key stability - Hash-based filename generation could cause cache misses (libs/pandautils/src/main/java/com/instructure/pandautils/loaders/OpenMediaAsyncTaskLoader.kt:170)
• MimeType state pollution - Instance variable reuse could cause incorrect mimeType associations (libs/pandautils/src/main/java/com/instructure/pandautils/loaders/OpenMediaAsyncTaskLoader.kt:333)

Overall Assessment

The core idea of this refactoring is sound - removing unnecessary network requests and complexity. However, there are several implementation issues around state management, error handling, and edge cases that should be addressed before merging. The inline comments provide specific suggestions for each issue.

Testing Recommendations

Please verify:

1. Media playback with query parameters in URLs (e.g., video.mp4?token=xyz&expires=123)
2. DASH videos without .mpd extensions retry correctly and don't cause issues on subsequent playback attempts
3. Concurrent media file downloads don't interfere with each other
4. Cached files are properly reused across app sessions

[github-actions]

🧪 Unit Test Results

✅ 📱 Student App

• Tests: 1226 total, 0 failed, 0 skipped
• Duration: 0.000s
• Success Rate: 100%

✅ 📱 Teacher App

• Tests: 364 total, 0 failed, 0 skipped
• Duration: 38.230s
• Success Rate: 100%

✅ 🌅 Horizon

• Tests: 449 total, 0 failed, 0 skipped
• Duration: 29.995s
• Success Rate: 100%

✅ 📦 Submodules

• Tests: 2414 total, 0 failed, 0 skipped
• Duration: 43.871s
• Success Rate: 100%

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📊 Summary

• Total Tests: 4453
• Failed: 0
• Skipped: 0
• Status: ✅ All tests passed!

Last updated: Wed, 10 Dec 2025 12:40:07 GMT

[github-actions]

Teacher Install Page

[github-actions]

Student Install Page

[adamNagy56]

QA +1