Feat: add UseEmulator to storage api

[AustinBenoit]

Description

Provide details of the change, and generalize the change in the PR title above.

Add support for Firebase Storage emulator via UseEmulator.

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Testing

Describe how you've tested these changes. Link any manually triggered Integration tests or CPP binary SDK Packaging Github Action workflows, if applicable.

Tested this manually via unity for Desktop, Android, iOS. See the photos below:

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Type of Change

Place an x the applicable box:

• Bug fix. Add the issue # below if applicable.
• New feature. A non-breaking change which adds functionality.
• Other, such as a build process or documentation change.

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Notes

• Bug fixes and feature changes require an update to the Release Notes section of release_build_files/readme.md.
• Read the contribution guidelines CONTRIBUTING.md.
• Changes to the public API require an internal API review. If you'd like to help us make Firebase APIs better, please propose your change in a feature request so that we can discuss it together.

[gemini-code-assist]

Summary of Changes

Hello @AustinBenoit, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the Firebase Storage SDK by adding support for the Firebase Storage emulator. This feature allows developers to test their applications against a local, emulated backend, which can greatly improve development speed, reduce costs associated with cloud usage, and enable offline testing scenarios. The implementation ensures that the emulator can be configured across all supported platforms before any storage operations are performed.

Highlights

• Firebase Storage Emulator Support: Introduced a new UseEmulator method in the Storage API, allowing developers to connect to a local Firebase Storage emulator instead of the default remote backend.
• Cross-Platform Implementation: The emulator support has been implemented across Android, iOS, and Desktop platforms, ensuring consistent functionality.
• Usage Requirement: The UseEmulator method must be called before any other Storage API methods are invoked on a new instance of Storage to properly configure the connection. The default port for the emulator is 9199.
• URL Construction Logic Update: Refactored the internal URL construction logic to dynamically use the configured host, port, and scheme, enabling seamless switching between remote and emulated backends.

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[gemini-code-assist]

Code Review

This pull request adds support for using the Firebase Storage emulator across Android, iOS, and desktop platforms. The changes are well-structured, introducing a new UseEmulator method to the public API and implementing it for each platform.

My review has identified a few issues:

• An uninitialized member variable in the desktop implementation which could lead to undefined behavior.
• The use of debug-only assertions for input validation in the iOS implementation, which would be stripped in release builds.
• A minor formatting inconsistency in the release notes.

I've provided suggestions to address these points. Overall, this is a great addition to the SDK.

[gemini-code-assist]

NSCAssert is a debug-only assertion and is stripped from release builds. This leaves the host and port parameters unvalidated in release builds, which could lead to crashes or other undefined behavior if invalid values are passed. It's better to use runtime checks that are present in all build configurations to ensure robustness.

  if (!(host && host[0] != '\0')) {
    LogError("Emulator host cannot be null or empty.");
    return;
  }

  if (!(port > 0)) {
    LogError("Emulator port must be a positive number.");
    return;
  }

[github-actions]

✅  Integration test succeeded!

Requested by @AustinBenoit on commit b4de53c
Last updated: Wed Oct 22 14:25 PDT 2025
View integration test log & download artifacts

[a-maurice]

LGTM, but should wait until the API review has been handled before submitting