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flipt-client-swift

README.md

Flipt Client Swift

Client tag

The flipt-client-swift library contains the Swift source code for the Flipt client-side evaluation client.

Installation

Swift Package Manager

Add the following to your Package.swift file:

dependencies: [
    .package(url: "https://github.com/flipt-io/flipt-client-swift.git", from: "0.0.1")
]

Or add it directly through Xcode:

  1. File > Add Package Dependencies
  2. Enter package URL: https://github.com/flipt-io/flipt-client-swift

How Does It Work?

The flipt-client-swift library is a wrapper around the flipt-engine-ffi library.

All evaluation happens within the SDK, using the shared library built from the flipt-engine-ffi library.

Because the evaluation happens within the SDK, the SDKs can be used in environments where the Flipt server is not available or reachable after the initial data is fetched.

Data Fetching

Upon instantiation, the flipt-client-swift library will fetch the flag state from the Flipt server and store it in memory. This means that the first time you use the SDK, it will make a request to the Flipt server.

Polling (Default)

By default, the SDK will poll the Flipt server for new flag state at a regular interval. This interval can be configured using the updateInterval option when constructing a client. The default interval is 120 seconds.

Streaming (Flipt Cloud Only)

Flipt Cloud users can use the streaming fetch method to stream flag state changes from the Flipt server to the SDK.

When in streaming mode, the SDK will connect to the Flipt server and open a persistent connection that will remain open until the client is closed. The SDK will then receive flag state changes in real-time.

Supported Platforms

This SDK currently supports the following platforms/architectures:

  • iOS arm64
  • iOS Simulator arm64
  • macOS arm64

Usage

import FliptClient

// Initialize the client
let client = try FliptClient(
    namespace: "default",
    url: "http://localhost:8080",
    authentication: .clientToken("your-token"),
    updateInterval: 120,
    fetchMode: .polling
)

// Evaluate a boolean flag
let boolResult = try client.evaluateBoolean(
    flagKey: "my-flag",
    entityId: "user-123",
    context: ["key": "value"]
)
print("Flag enabled: \(boolResult.enabled)")

// Evaluate a variant flag
let variantResult = try client.evaluateVariant(
    flagKey: "my-variant-flag",
    entityId: "user-123",
    context: ["key": "value"]
)
print("Variant key: \(variantResult.variantKey)")

// Don't forget to close the client when you're done
defer {
    client.close()
}

Authentication

The FliptClient supports the following authentication strategies:

Memory Management

The engine that is allocated on the Rust side to compute evaluations for flag state will not be properly deallocated unless you call the close() method on a FliptClient instance.

Please be sure to do this to avoid leaking memory!

defer {
    client.close()
}

Contributing

Contributions are welcome! Please feel free to open an issue or submit a Pull Request.

License

This project is licensed under the MIT License.