Fix/base64 encoding

[RickyJam]

Summary

This PR replaces the usage of java.util.Base64 with android.util.Base64 to ensure full compatibility across all supported Android API levels.

Problem

• java.util.Base64 is not available to android SDK < 26, but the minSdk is 24. This results in java.lang.NoClassDefFoundError: java.util.Base64 that stops google auth process.

Proposed Solution

• replace the current java.util.Base64 with the most appropriate andorid.util.Base64 in order to grant backwards compatibility to < 26 android versions.

Testing

• Tested on devices/emulators with API < 26 and API ≥ 26

Summary by CodeRabbit

• Refactor
  • Authentication module optimized for improved platform compatibility.

[coderabbitai]

📝 Walkthrough

Walkthrough

Replaced Base64 decoding implementation in Android module from java.util.Base64.getUrlDecoder() to android.util.Base64.decode() with URL_SAFE flag. Updated corresponding imports accordingly.

Changes

Cohort / File(s)	Summary
Base64 Decoding Refactor android/src/main/java/com/googleauth/GoogleAuthModule.kt	Replaced java.util.Base64.getUrlDecoder().decode() calls with android.util.Base64.decode(..., Base64.URL_SAFE) for token parsing and email extraction. Updated imports by removing java.util.Date, java.util.concurrent.TimeUnit, and java.util.Base64; added android.util.Base64. No public API signature changes.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A decoder's journey from Java's grand base,
To Android's swift embrace,
URL_SAFE flags now guard the token's flight,
One file transformed—the imports aligned just right,
No API breaks, just cleaner ways to decode! ✨

🚥 Pre-merge checks | ✅ 1 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

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.
Title check	❓ Inconclusive	The title 'Fix/base64 encoding' is vague and generic, using non-descriptive phrasing that doesn't clearly convey what was fixed or why it matters.	Consider using a more specific title that explains the actual fix, such as 'Replace java.util.Base64 with android.util.Base64 for API level compatibility' or 'Fix Android API level compatibility by switching to android.util.Base64'.

✅ Passed checks (1 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[coderabbitai]

🧹 Nitpick comments (1)

android/src/main/java/com/googleauth/GoogleAuthModule.kt (1)

867-867: Specify UTF-8 charset explicitly when decoding JWT payload.

String(ByteArray) uses the platform default charset. JWT payloads are defined as UTF-8 JSON. While the default is almost always UTF-8 on Android, it's safer to be explicit.

Proposed fix

-        val payload = String(Base64.decode(parts[1], Base64.URL_SAFE))
+        val payload = String(Base64.decode(parts[1], Base64.URL_SAFE), Charsets.UTF_8)

Apply in both parseTokenExpiration (Line 867) and extractEmailFromIdToken (Line 883).

Also applies to: 883-883

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@android/src/main/java/com/googleauth/GoogleAuthModule.kt` at line 867, The
JWT payload is decoded using the platform default charset; update both
parseTokenExpiration and extractEmailFromIdToken to construct the String from
the decoded bytes with an explicit UTF-8 charset (use the result of
Base64.decode(parts[1], Base64.URL_SAFE) and pass it to String(...,
Charsets.UTF_8)) so the JWT JSON is always interpreted as UTF-8.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@android/src/main/java/com/googleauth/GoogleAuthModule.kt`:
- Line 867: The JWT payload is decoded using the platform default charset;
update both parseTokenExpiration and extractEmailFromIdToken to construct the
String from the decoded bytes with an explicit UTF-8 charset (use the result of
Base64.decode(parts[1], Base64.URL_SAFE) and pass it to String(...,
Charsets.UTF_8)) so the JWT JSON is always interpreted as UTF-8.

[RickyJam]

@sbaiahmed1