OpenFeature

https://openfeature.dev/docs/
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### Run Dart Pub Get

Source: https://openfeature.dev/docs/reference/sdks/server/dart

Command to install the added dependencies.

```bash
dart pub get  
```

--------------------------------

### Go Examples

Source: https://openfeature.dev/docs/reference/concepts/evaluation-api

Examples of how to get detailed evaluation results for different data types using the OpenFeature client in Go.

```APIDOC
## BooleanValueDetails

### Description
Retrieves detailed evaluation results for a boolean feature flag.

### Method
`client.BooleanValueDetails(ctx context.Context, flagKey string, defaultValue bool, context openfeature.EvaluationContext) (bool, error)`

### Parameters
- **ctx** (context.Context) - Required - The context for the evaluation.
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (bool) - Required - The default value to return if the flag is not found or an error occurs.
- **context** (openfeature.EvaluationContext) - Required - The evaluation context.

### Request Example
```go
boolDetails, err := client.BooleanValueDetails(context.Background(), "boolFlag", false, openfeature.EvaluationContext{})
```

## StringValueDetails

### Description
Retrieves detailed evaluation results for a string feature flag.

### Method
`client.StringValueDetails(ctx context.Context, flagKey string, defaultValue string, context openfeature.EvaluationContext) (string, error)`

### Parameters
- **ctx** (context.Context) - Required - The context for the evaluation.
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (string) - Required - The default value to return if the flag is not found or an error occurs.
- **context** (openfeature.EvaluationContext) - Required - The evaluation context.

### Request Example
```go
stringDetails, err := client.StringValueDetails(context.Background(), "stringFlag", "default", openfeature.EvaluationContext{})
```

## IntValueDetails

### Description
Retrieves detailed evaluation results for an integer feature flag.

### Method
`client.IntValueDetails(ctx context.Context, flagKey string, defaultValue int, context openfeature.EvaluationContext) (int, error)`

### Parameters
- **ctx** (context.Context) - Required - The context for the evaluation.
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (int) - Required - The default value to return if the flag is not found or an error occurs.
- **context** (openfeature.EvaluationContext) - Required - The evaluation context.

### Request Example
```go
intDetails, err := client.IntValueDetails(context.Background(), "intFlag", 1, openfeature.EvaluationContext{})
```

## FloatValueDetails

### Description
Retrieves detailed evaluation results for a float feature flag.

### Method
`client.FloatValueDetails(ctx context.Context, flagKey string, defaultValue float64, context openfeature.EvaluationContext) (float64, error)`

### Parameters
- **ctx** (context.Context) - Required - The context for the evaluation.
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (float64) - Required - The default value to return if the flag is not found or an error occurs.
- **context** (openfeature.EvaluationContext) - Required - The evaluation context.

### Request Example
```go
floatDetails, err := client.FloatValueDetails(context.Background(), "floatFlag", 3.14, openfeature.EvaluationContext{})
```

## ObjectValueDetails

### Description
Retrieves detailed evaluation results for an object feature flag.

### Method
`client.ObjectValueDetails(ctx context.Context, flagKey string, defaultValue interface{}, context openfeature.EvaluationContext) (interface{}, error)`

### Parameters
- **ctx** (context.Context) - Required - The context for the evaluation.
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (interface{}) - Required - The default value to return if the flag is not found or an error occurs.
- **context** (openfeature.EvaluationContext) - Required - The evaluation context.

### Request Example
```go
objectDetails, err := client.ObjectValueDetails(context.Background(), "objectFlag", myObject, openfeature.EvaluationContext{})
```
```

--------------------------------

### Run Logging Example in Rust

Source: https://openfeature.dev/docs/reference/sdks/server/rust

Execute the logging example provided with the Rust SDK. This command runs the example and outputs log messages.

```bash
cargo run --example logging
```

--------------------------------

### Run Hook Example

Source: https://openfeature.dev/docs/reference/sdks/server/rust

Execute the example code for hooks located in examples/hooks.rs using cargo.

```bash
cargo run --example hooks
```

--------------------------------

### Running the OpenFeature Server with Provider

Source: https://openfeature.dev/docs/tutorials/five-minutes-to-feature-flags

Starts the Node.js server configured with the InMemoryProvider for OpenFeature. Ensure Node.js is installed.

```bash
node 04_openfeature_with_provider.js  
```

--------------------------------

### PHP Examples

Source: https://openfeature.dev/docs/reference/concepts/evaluation-api

Examples of how to get detailed evaluation results for different data types using the OpenFeature client in PHP.

```APIDOC
## getBooleanDetails

### Description
Retrieves detailed evaluation results for a boolean feature flag.

### Method
`client->getBooleanDetails(string $flagKey, bool $defaultValue, ?EvaluationContext $context = null, ?Hook $hook = null)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (bool) - Required - The default value to return if the flag is not found or an error occurs.
- **context** (EvaluationContext) - Optional - The evaluation context.
- **hook** (Hook) - Optional - A hook to be executed during evaluation.

### Request Example
```php
$boolDetails = $client->getBooleanDetails("boolFlag", false, null, null);
```

## getStringDetails

### Description
Retrieves detailed evaluation results for a string feature flag.

### Method
`client->getStringDetails(string $flagKey, string $defaultValue, ?EvaluationContext $context = null, ?Hook $hook = null)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (string) - Required - The default value to return if the flag is not found or an error occurs.
- **context** (EvaluationContext) - Optional - The evaluation context.
- **hook** (Hook) - Optional - A hook to be executed during evaluation.

### Request Example
```php
$stringDetails = $client->getStringDetails("stringFlag", "default", null, null);
```

## getIntegerDetails

### Description
Retrieves detailed evaluation results for an integer feature flag.

### Method
`client->getIntegerDetails(string $flagKey, int $defaultValue, ?EvaluationContext $context = null, ?Hook $hook = null)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (int) - Required - The default value to return if the flag is not found or an error occurs.
- **context** (EvaluationContext) - Optional - The evaluation context.
- **hook** (Hook) - Optional - A hook to be executed during evaluation.

### Request Example
```php
$intDetails = $client->getIntegerDetails("intFlag", 1, null, null);
```

## getFloatDetails

### Description
Retrieves detailed evaluation results for a float feature flag.

### Method
`client->getFloatDetails(string $flagKey, float $defaultValue, ?EvaluationContext $context = null, ?Hook $hook = null)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (float) - Required - The default value to return if the flag is not found or an error occurs.
- **context** (EvaluationContext) - Optional - The evaluation context.
- **hook** (Hook) - Optional - A hook to be executed during evaluation.

### Request Example
```php
$floatDetails = $client->getFloatDetails("floatFlag", 0.9, null, null);
```

## getObjectDetails

### Description
Retrieves detailed evaluation results for an object feature flag.

### Method
`client->getObjectDetails(string $flagKey, mixed $defaultValue, ?EvaluationContext $context = null, ?Hook $hook = null)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (mixed) - Required - The default value to return if the flag is not found or an error occurs.
- **context** (EvaluationContext) - Optional - The evaluation context.
- **hook** (Hook) - Optional - A hook to be executed during evaluation.

### Request Example
```php
$objectDetails = $client->getObjectDetails("objectFlag", $myObjectInstance, null, null);
```
```

--------------------------------

### Running the OpenFeature Server

Source: https://openfeature.dev/docs/tutorials/five-minutes-to-feature-flags

Starts the Node.js server for the OpenFeature integration. Ensure you have Node.js installed.

```bash
node 03_openfeature.js  
```

--------------------------------

### Java Examples

Source: https://openfeature.dev/docs/reference/concepts/evaluation-api

Examples of how to get detailed evaluation results for different data types using the OpenFeature client in Java.

```APIDOC
## getBooleanDetails

### Description
Retrieves detailed evaluation results for a boolean feature flag.

### Method
`client.getBooleanDetails(String flagKey, boolean defaultValue)`

### Parameters
- **flagKey** (String) - Required - The unique identifier for the feature flag.
- **defaultValue** (boolean) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```java
FlagEvaluationDetails<Boolean> boolDetails = client.getBooleanDetails("boolFlag", false);
```

## getStringDetails

### Description
Retrieves detailed evaluation results for a string feature flag.

### Method
`client.getStringDetails(String flagKey, String defaultValue)`

### Parameters
- **flagKey** (String) - Required - The unique identifier for the feature flag.
- **defaultValue** (String) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```java
FlagEvaluationDetails<String> stringDetails = client.getStringDetails("stringFlag", "default");
```

## getIntegerDetails

### Description
Retrieves detailed evaluation results for an integer feature flag.

### Method
`client.getIntegerDetails(String flagKey, int defaultValue)`

### Parameters
- **flagKey** (String) - Required - The unique identifier for the feature flag.
- **defaultValue** (int) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```java
FlagEvaluationDetails<Integer> intDetails = client.getIntegerDetails("intFlag", 1);
```

## getDoubleDetails

### Description
Retrieves detailed evaluation results for a double feature flag.

### Method
`client.getDoubleDetails(String flagKey, double defaultValue)`

### Parameters
- **flagKey** (String) - Required - The unique identifier for the feature flag.
- **defaultValue** (double) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```java
FlagEvaluationDetails<Double> doubleDetails = client.getDoubleDetails("doubleFlag", .9);
```

## getObjectDetails

### Description
Retrieves detailed evaluation results for an object feature flag.

### Method
`client.getObjectDetails(String flagKey, Object defaultValue)`

### Parameters
- **flagKey** (String) - Required - The unique identifier for the feature flag.
- **defaultValue** (Object) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```java
FlagEvaluationDetails<Value> objectDetails = client.getObjectDetails<MyObject>("objectFlag", myObjectDefaultInstance);
```
```

--------------------------------

### NPX Install for OpenFeature MCP Server

Source: https://openfeature.dev/docs/reference/other-technologies/mcp

Use NPX for a quick setup without global installation. This command installs and runs the MCP server.

```json
{
  "mcpServers": {
    "OpenFeature": {
      "command": "npx",
      "args": ["-y", "@openfeature/mcp"]
    }
  }
}
```

--------------------------------

### Install OpenFeature React SDK with yarn

Source: https://openfeature.dev/docs/reference/sdks/client/web/react

Use this command to install the React SDK using yarn. Manual installation of peer dependencies is required.

```bash
# yarn requires manual installation of the peer dependencies (see below)  
yarn add @openfeature/react-sdk @openfeature/web-sdk @openfeature/core  
```

--------------------------------

### C# Examples

Source: https://openfeature.dev/docs/reference/concepts/evaluation-api

Examples of how to get detailed evaluation results for different data types using the OpenFeature client in C#.

```APIDOC
## GetBooleanDetails

### Description
Retrieves detailed evaluation results for a boolean feature flag.

### Method
`client.GetBooleanDetails(string flagKey, bool defaultValue)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (bool) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```csharp
var boolDetails = await client.GetBooleanDetails("boolFlag", false);
```

## GetStringDetails

### Description
Retrieves detailed evaluation results for a string feature flag.

### Method
`client.GetStringDetails(string flagKey, string defaultValue)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (string) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```csharp
var stringDetails = await client.GetStringDetails("stringFlag", "default");
```

## GetIntegerDetails

### Description
Retrieves detailed evaluation results for an integer feature flag.

### Method
`client.GetIntegerDetails(string flagKey, int defaultValue)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (int) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```csharp
var intDetails = await client.GetIntegerDetails("intFlag", 1);
```

## GetDoubleDetails

### Description
Retrieves detailed evaluation results for a double feature flag.

### Method
`client.GetDoubleDetails(string flagKey, double defaultValue)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (double) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```csharp
var doubleDetails = await client.GetDoubleDetails("doubleFlag", 1);
```

## GetObjectDetails

### Description
Retrieves detailed evaluation results for an object feature flag.

### Method
`client.GetObjectDetails(string flagKey, object defaultValue)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (object) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```csharp
var objectDetails = await client.GetObjectDetails("objectFlag", myObjectDefaultInstance);
```
```

--------------------------------

### Configure MultiProvider Strategy

Source: https://openfeature.dev/docs/reference/sdks/server/php

Example of initializing the MultiProvider with a specific evaluation strategy.

```php
use OpenFeature\implementation\multiprovider\strategy\FirstSuccessfulStrategy;  

  

$multiProvider = new MultiProvider([  

    ['provider' => new ProviderA()],  

    ['provider' => new ProviderB()],  

], new FirstSuccessfulStrategy());
```

--------------------------------

### Python Examples

Source: https://openfeature.dev/docs/reference/concepts/evaluation-api

Examples of how to get detailed evaluation results for different data types using the OpenFeature client in Python.

```APIDOC
## get_boolean_details

### Description
Retrieves detailed evaluation results for a boolean feature flag.

### Method
`client.get_boolean_details(flag_key: str, default_value: bool)`

### Parameters
- **flag_key** (str) - Required - The unique identifier for the feature flag.
- **default_value** (bool) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```python
details = client.get_boolean_details("boolFlag", False)
```

## get_string_details

### Description
Retrieves detailed evaluation results for a string feature flag.

### Method
`client.get_string_details(flag_key: str, default_value: str)`

### Parameters
- **flag_key** (str) - Required - The unique identifier for the feature flag.
- **default_value** (str) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```python
details = client.get_string_details("stringFlag", "default")
```

## get_integer_details

### Description
Retrieves detailed evaluation results for an integer feature flag.

### Method
`client.get_integer_details(flag_key: str, default_value: int)`

### Parameters
- **flag_key** (str) - Required - The unique identifier for the feature flag.
- **default_value** (int) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```python
details = client.get_integer_details("intFlag", 1)
```

## get_float_details

### Description
Retrieves detailed evaluation results for a float feature flag.

### Method
`client.get_float_details(flag_key: str, default_value: float)`

### Parameters
- **flag_key** (str) - Required - The unique identifier for the feature flag.
- **default_value** (float) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```python
details = client.get_float_details("floatFlag", 1)
```

## get_object_details

### Description
Retrieves detailed evaluation results for an object feature flag.

### Method
`client.get_object_details(flag_key: str, default_value: dict)`

### Parameters
- **flag_key** (str) - Required - The unique identifier for the feature flag.
- **default_value** (dict) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```python
details = client.get_object_details("objectFlag", {{}})
```
```

--------------------------------

### Installation

Source: https://openfeature.dev/docs/reference/sdks/server/ruby

Install the OpenFeature SDK gem and add it to your application's Gemfile.

```APIDOC
bundle add openfeature-sdk
```

```APIDOC
gem install openfeature-sdk
```

--------------------------------

### Install Server SDK via yarn

Source: https://openfeature.dev/docs/reference/sdks/server/javascript

Install the OpenFeature Server SDK and its core dependency using yarn. Manual installation of @openfeature/core is required.

```bash
# yarn requires manual installation of the @openfeature/core peer-dependency
yarn add @openfeature/server-sdk @openfeature/core
```

--------------------------------

### Configure Evaluation Strategies

Source: https://openfeature.dev/docs/reference/sdks/server/dotnet

Examples of initializing the Multi-Provider with different evaluation strategies.

```csharp
var multiProvider = new MultiProvider(providerEntries, new FirstMatchStrategy());
```

```csharp
var multiProvider = new MultiProvider(providerEntries, new FirstSuccessfulStrategy());
```

```csharp
// Basic comparison  

var multiProvider = new MultiProvider(providerEntries, new ComparisonStrategy());  

  

// With fallback provider  

var multiProvider = new MultiProvider(providerEntries,  

    new ComparisonStrategy(fallbackProvider: provider1));  

  

// With mismatch callback  

var multiProvider = new MultiProvider(providerEntries,  

    new ComparisonStrategy(onMismatch: (mismatchDetails) => {  

        // Log or handle mismatches between providers  

        foreach (var kvp in mismatchDetails)  

        {  

            Console.WriteLine($"Provider {kvp.Key}: {kvp.Value}");  

        }  

    }));
```

--------------------------------

### Install via npm

Source: https://openfeature.dev/docs/reference/sdks/client/web/angular

Command to install the Angular SDK using npm.

```bash

npm install --save @openfeature/angular-sdk  


```

--------------------------------

### Install OpenFeature Hosting Package

Source: https://openfeature.dev/docs/reference/sdks/server/dotnet

Command to add the experimental OpenFeature.Hosting package to your .NET project.

```bash
dotnet add package OpenFeature.Hosting
```

--------------------------------

### Install OpenFeature React SDK with npm

Source: https://openfeature.dev/docs/reference/sdks/client/web/react

Use this command to install the React SDK using npm.

```bash
npm install --save @openfeature/react-sdk  
```

--------------------------------

### Install OpenFeature Web SDK via yarn

Source: https://openfeature.dev/docs/reference/sdks/client/web

Use yarn to install the OpenFeature Web SDK. Note that yarn requires manual installation of the @openfeature/core peer-dependency.

```bash
# yarn requires manual installation of the @openfeature/core peer-dependency

yarn add @openfeature/web-sdk @openfeature/core
```

--------------------------------

### Run Structured Logging Example in Rust

Source: https://openfeature.dev/docs/reference/sdks/server/rust

Execute the logging example with the 'structured-logging' feature enabled. This command runs the example and outputs structured log messages.

```bash
cargo run --example logging --features structured-logging
```

--------------------------------

### Basic Express Server Setup

Source: https://openfeature.dev/docs/tutorials/five-minutes-to-feature-flags

A minimal Express.js server with a single endpoint that returns 'Hello, world!'.

```javascript
import express from 'express';  
import Router from 'express-promise-router';  
  
const app = express();  
const routes = Router();  
app.use((_, res, next) => {  
  res.setHeader('content-type', 'text/plain');  
  next();  
}, routes);  
  
routes.get('/', async (_, res) => {  
  res.send('Hello, world!');  
});  
  
app.listen(3333, () => {  
  console.log('Server running at http://localhost:3333');  
});  

```

--------------------------------

### Initialize MultiProvider

Source: https://openfeature.dev/docs/reference/sdks/server/php

Basic setup for initializing the MultiProvider with an array of providers and setting it as the global provider.

```php
use OpenFeature\OpenFeatureAPI;  

use OpenFeature\implementation\multiprovider\MultiProvider;  

  

$multiProvider = new MultiProvider([  

    ['provider' => new ProviderA()],  

    ['provider' => new ProviderB()],  

]);  

  

$api = OpenFeatureAPI::getInstance();  

$api->setProvider($multiProvider);  

  

$client = $api->getClient();  

echo $client->getBooleanValue('my-flag', false);
```

--------------------------------

### Install NestJS SDK with npm

Source: https://openfeature.dev/docs/reference/sdks/server/javascript/nestjs

Install the OpenFeature NestJS SDK using npm.

```bash
npm install --save @openfeature/nestjs-sdk
```

--------------------------------

### Install OpenFeature SDK via Pip

Source: https://openfeature.dev/docs/reference/sdks/server/python

Standard installation command for the OpenFeature Python SDK.

```bash
pip install openfeature-sdk==0.10.0
```

--------------------------------

### Install via yarn

Source: https://openfeature.dev/docs/reference/sdks/client/web/angular

Command to install the Angular SDK and required peer dependencies using yarn.

```bash

# yarn requires manual installation of the peer dependencies (see below)  

yarn add @openfeature/angular-sdk @openfeature/web-sdk @openfeature/core  


```

--------------------------------

### Initialize and Configure OpenFeature SDK

Source: https://openfeature.dev/docs/reference/sdks/server/ruby

Initialize the OpenFeature SDK and configure a default provider. This example uses an InMemoryProvider with predefined flag values.

```ruby
require 'open_feature/sdk'

# API Initialization and configuration

OpenFeature::SDK.configure do |config|
  # your provider of choice, which will be used as the default provider
  config.set_provider(OpenFeature::SDK::Provider::InMemoryProvider.new(
    {
      "flag1" => true,
      "flag2" => 1
    }
  ))
end

# Create a client
client = OpenFeature::SDK.build_client

# fetching boolean value feature flag
bool_value = client.fetch_boolean_value(flag_key: 'boolean_flag', default_value: false)

# a details method is also available for more information about the flag evaluation
# see `EvaluationDetails` for more info
bool_details = client.fetch_boolean_details(flag_key: 'boolean_flag', default_value: false)

# fetching string value feature flag
string_value = client.fetch_string_value(flag_key: 'string_flag', default_value: 'default')

# fetching number value feature flag
float_value = client.fetch_number_value(flag_key: 'number_value', default_value: 1.0)
integer_value = client.fetch_number_value(flag_key: 'number_value', default_value: 1)

# get an object value
object = client.fetch_object_value(flag_key: 'object_value', default_value: { name: 'object'})

```

--------------------------------

### Clone and Install Project Dependencies

Source: https://openfeature.dev/docs/tutorials/five-minutes-to-feature-flags

Clone the repository and install project dependencies using npm.

```bash
git clone https://github.com/open-feature/five-minutes-to-feature-flags.git && \
  cd five-minutes-to-feature-flags && \
  npm install  

```

--------------------------------

### Install Server SDK via npm

Source: https://openfeature.dev/docs/reference/sdks/server/javascript

Install the OpenFeature Server SDK using npm. Ensure you are using Node.js version 18 or higher.

```bash
npm install --save @openfeature/server-sdk
```

--------------------------------

### Create Node.js Project (JavaScript)

Source: https://openfeature.dev/docs/tutorials/getting-started/node

Bootstrap a new Node.js project and install Express for JavaScript.

```bash
mkdir openfeature-js-intro
cd openfeature-js-intro
npm init -y
npm install express
```

--------------------------------

### OFREP Configuration File Example

Source: https://openfeature.dev/docs/reference/other-technologies/mcp

Example of a configuration file for OFREP, specifying base URL, authentication, headers, and timeout. This file can be overridden by the OPENFEATURE_MCP_CONFIG_PATH environment variable.

```json
{
  "OFREP": {
    "baseUrl": "https://flags.example.com",
    "bearerToken": "<your-token>",
    "apiKey": "<your-api-key>",
    "headers": {
      "X-Custom-Header": "value"
    },
    "timeoutMs": 5000
  }
}
```

--------------------------------

### Text Logging Output Example

Source: https://openfeature.dev/docs/reference/sdks/server/rust

Example output from the logging hook when text logging is enabled.

```text
[2025-01-10T18:53:11Z DEBUG open_feature::hooks::logging] Before stage: domain=, provider_name=Dummy Provider, flag_key=my_feature, default_value=Some(Bool(false)), evaluation_context=EvaluationContext { targeting_key: None, custom_fields: {} }
[2025-01-10T18:53:11Z DEBUG open_feature::hooks::logging] After stage: domain=, provider_name=Dummy Provider, flag_key=my_feature, default_value=Some(Bool(false)), reason=None, variant=None, value=Bool(true), evaluation_context=EvaluationContext { targeting_key: None, custom_fields: {} }
```

--------------------------------

### Install OpenFeature SDK Gem

Source: https://openfeature.dev/docs/reference/sdks/server/ruby

Install the openfeature-sdk gem directly if you are not using bundler to manage dependencies.

```bash
gem install openfeature-sdk
```

--------------------------------

### Install OpenFeature CLI via Go

Source: https://openfeature.dev/docs/reference/other-technologies/cli

Installs the OpenFeature CLI using the Go package manager for Go version 1.25 and above.

```bash
go install github.com/open-feature/cli/cmd/openfeature@latest  
```

--------------------------------

### Install OpenFeature Web SDK via npm

Source: https://openfeature.dev/docs/reference/sdks/client/web

Use npm to install the OpenFeature Web SDK. This is the standard package manager for Node.js and front-end projects.

```bash
npm install --save @openfeature/web-sdk
```

--------------------------------

### Initialize and Use OpenFeature Client

Source: https://openfeature.dev/docs/reference/sdks/server/dart

Basic setup using an InMemoryProvider and retrieving flag values.

```dart
import 'package:openfeature_dart_server_sdk/feature_provider.dart';  

import 'package:openfeature_dart_server_sdk/open_feature_api.dart';  

  

void main() async {  

  final api = OpenFeatureAPI();  

  

  await api.setProviderAndWait(  

    InMemoryProvider({  

      'new-feature': true,  

      'welcome-message': 'Hello, OpenFeature!',  

    }),  

  );  

  

  final client = api.getClient('my-app');  

  final newFeatureEnabled = await client.getBooleanFlag(  

    'new-feature',  

    defaultValue: false,  

  );  

  

  final details = await client.getBooleanDetails(  

    'new-feature',  

    defaultValue: false,  

  );  

  print('Reason: ${details.reason}, Variant: ${details.variant}');  

  

  if (newFeatureEnabled) {  

    final welcomeMessage = await client.getStringFlag(  

      'welcome-message',  

      defaultValue: 'Welcome!',  

    );  

    print(welcomeMessage);  

  }  

}  
```

--------------------------------

### Run Server with Basic Flag Configuration

Source: https://openfeature.dev/docs/tutorials/five-minutes-to-feature-flags

Execute the Node.js script to start the Express server with the basic feature flag.

```bash
node 02_basic_flags.js  

```

--------------------------------

### Install NestJS SDK with yarn

Source: https://openfeature.dev/docs/reference/sdks/server/javascript/nestjs

Install the OpenFeature NestJS SDK and its peer dependencies using yarn.

```bash
yarn add @openfeature/nestjs-sdk @openfeature/server-sdk @openfeature/core
```

--------------------------------

### Run Basic Express Server

Source: https://openfeature.dev/docs/tutorials/five-minutes-to-feature-flags

Execute the Node.js script to start the basic Express server.

```bash
node 01_vanilla.js  

```

--------------------------------

### Configure AI Assistant with Global MCP Install

Source: https://openfeature.dev/docs/reference/other-technologies/mcp

Configure your AI assistant to use the globally installed MCP server by specifying the `openfeature-mcp` command.

```json
{
  "mcpServers": {
    "OpenFeature": {
      "command": "openfeature-mcp"
    }
  }
}
```

--------------------------------

### Run Express App (JavaScript)

Source: https://openfeature.dev/docs/tutorials/getting-started/node

Start the Express server using Node.js.

```bash
node index.js
```

--------------------------------

### API Initialization and Configuration

Source: https://openfeature.dev/docs/reference/sdks/server/ruby

Configure the OpenFeature SDK by setting a default provider. The example uses an InMemoryProvider.

```APIDOC
require 'open_feature/sdk'

OpenFeature::SDK.configure do |config|
  config.set_provider(OpenFeature::SDK::Provider::InMemoryProvider.new({
    "flag1" => true,
    "flag2" => 1
  }))
end
```

--------------------------------

### Create Node.js Project (TypeScript)

Source: https://openfeature.dev/docs/tutorials/getting-started/node

Bootstrap a new Node.js project and install Express and TypeScript dependencies for TypeScript.

```bash
mkdir openfeature-ts-intro
cd openfeature-ts-intro
npm init -y
npm install express
npm i -D typescript @types/express @types/node ts-node
npx tsc --init
```

--------------------------------

### Set up Go Gin Application

Source: https://openfeature.dev/docs/tutorials/getting-started/go

Initialize a Go Gin web server with a basic '/hello' endpoint.

```go
package main

import (
    "github.com/gin-gonic/gin"
    "net/http"
)

const defaultMessage = "Hello!"

func main() {
    // Initialize Go Gin
    engine := gin.Default()

    // Setup a simple endpoint
    engine.GET("/hello", func(c *gin.Context) {
        c.JSON(http.StatusOK, defaultMessage)
    })

    engine.Run()
}
```

--------------------------------

### Run Sample Application

Source: https://openfeature.dev/docs/reference/sdks/server/dotnet

Commands to navigate to a sample directory and execute the application.

```bash
cd samples/AspNetCore
```

```bash
dotnet run
```

--------------------------------

### Provider Migration Example

Source: https://openfeature.dev/docs/reference/sdks/client/swift

Gradually migrate from an old provider to a new one by listing the new provider first in the MultiProvider.

```swift
let multiProvider = MultiProvider(providers: [
    NewProvider(), // Check new provider first
    OldProvider()  // Fall back to old provider
])
```

--------------------------------

### Initialize Go Project

Source: https://openfeature.dev/docs/tutorials/getting-started/go

Create a new directory and initialize a Go module for your project.

```bash
mkdir gostart

cd gostart

go mod init gostart
```

--------------------------------

### Print OpenFeature CLI Version

Source: https://openfeature.dev/docs/reference/other-technologies/cli

Display the installed version of the OpenFeature CLI using the 'version' command.

```bash
openfeature version
```

--------------------------------

### Install OpenFeature Dart Server SDK

Source: https://openfeature.dev/docs/reference/sdks/server/dart

Add the SDK dependency to your project's pubspec.yaml file.

```yaml
dependencies:  

  openfeature_dart_server_sdk: ^0.0.22  
```

--------------------------------

### Initialize .NET Project

Source: https://openfeature.dev/docs/reference/sdks/server/dotnet

Commands to create a new console project and add the OpenFeature package.

```bash
dotnet new console
```

```bash
dotnet add package OpenFeature
```

--------------------------------

### Evaluate Feature Flags in .NET

Source: https://openfeature.dev/docs/reference/sdks/server/dotnet

Example showing provider registration, client creation, and boolean flag evaluation.

```csharp
public async Task Example()  

{  

    // Register your feature flag provider  

    try  

    {  

        await Api.Instance.SetProviderAsync(new InMemoryProvider());  

    }  

    catch (Exception ex)  

    {  

        // Log error  

    }  

  

    // Create a new client  

    FeatureClient client = Api.Instance.GetClient();  

  

    // Evaluate your feature flag  

    bool v2Enabled = await client.GetBooleanValueAsync("v2_enabled", false);  

  

    if ( v2Enabled )  

    {  

        // Do some work  

    }  

}  
```

--------------------------------

### Basic OpenFeature SDK Usage in Rust

Source: https://openfeature.dev/docs/reference/sdks/server/rust

Demonstrates the basic setup and usage of the OpenFeature Rust SDK. It shows how to acquire an API instance, set a provider (defaulting to NoOpProvider), create a client, and retrieve a boolean flag value.

```rust
async fn example() -> Result<(), Error> {
  
    // Acquire an OpenFeature API instance.  

    // Note the `await` call here because asynchronous lock is used to  

    // guarantee thread safety.  

    let mut api = OpenFeature::singleton_mut().await;
  

    // Configure a provider.  

    // By default [`NoOpProvider`] is used.  

    api.set_provider(NoOpProvider::default()).await;
  

    // create a client  

    let client = api.create_client();
  

    // get a bool flag value  

    let is_feature_enabled = client

        .get_bool_value("v2_enabled", None, None)

        .await

        .unwrap_or(false);
  

    Ok(())

}

```

--------------------------------

### TypeScript Examples

Source: https://openfeature.dev/docs/reference/concepts/evaluation-api

Examples of how to get detailed evaluation results for different data types using the OpenFeature client in TypeScript.

```APIDOC
## getBooleanDetails

### Description
Retrieves detailed evaluation results for a boolean feature flag.

### Method
`client.getBooleanDetails(flagKey: string, defaultValue: boolean)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (boolean) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```typescript
const boolDetails = await client.getBooleanDetails('boolFlag', false);
```

## getStringDetails

### Description
Retrieves detailed evaluation results for a string feature flag.

### Method
`client.getStringDetails(flagKey: string, defaultValue: string)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (string) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```typescript
const stringDetails = await client.getStringDetails('stringFlag', 'default');
```

## getNumberDetails

### Description
Retrieves detailed evaluation results for a numeric feature flag.

### Method
`client.getNumberDetails(flagKey: string, defaultValue: number)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (number) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```typescript
const numberDetails = await client.getNumberDetails('intFlag', 1);
```

## getObjectDetails

### Description
Retrieves detailed evaluation results for an object feature flag.

### Method
`client.getObjectDetails<T>(flagKey: string, defaultValue: T)`

### Parameters
- **flagKey** (string) - Required - The unique identifier for the feature flag.
- **defaultValue** (T) - Required - The default value to return if the flag is not found or an error occurs.

### Request Example
```typescript
const objectDetails = await client.getObjectDetails<MyObject>('objectFlag', {});
```
```

--------------------------------

### Example .openfeature.yaml Configuration

Source: https://openfeature.dev/docs/reference/other-technologies/cli

This YAML file demonstrates how to configure the OpenFeature CLI, including overriding default paths for manifests, output directories, and language-specific settings.

```yaml
manifest: "flags/manifest.json" # Overrides the default manifest path

generate:
  output: "src/flags" # Overrides the default output directory

  # Any language-specific options can be specified here
  # For example, for React:
  react:
    output: "src/flags/react" # Overrides the default React output directory
  # For Go:
  go:
    package: "github.com/myorg/myrepo/flags" # Overrides the default Go package name
    output: "src/flags/go" # Overrides the default Go output directory
```

--------------------------------

### Create .NET Web Application

Source: https://openfeature.dev/docs/tutorials/getting-started/dotnet

Initializes a new ASP.NET Core Web API project and runs it. Use this to start a new .NET application.

```bash
dotnet new webapi -o openfeature-dotnet-sample

cd openfeature-dotnet-sample

dotnet run
```

--------------------------------

### Structured Logging Output Example

Source: https://openfeature.dev/docs/reference/sdks/server/rust

Example output from the logging hook when structured logging is enabled.

```json
{"default_value":"Some(Bool(false))","domain":"","evaluation_context":"EvaluationContext { targeting_key: None, custom_fields: {} }","flag_key":"my_feature","level":"DEBUG","message":"Before stage","provider_name":"No-op Provider","target":"open_feature","timestamp":1736537120828}
{"default_value":"Some(Bool(false))","domain":"","error_message":"Some(\"No-op provider is never ready\")","evaluation_context":"EvaluationContext { targeting_key: None, custom_fields: {} }","file":"src/hooks/logging.rs","flag_key":"my_feature","level":"ERROR","line":162,"message":"Error stage","module":"open_feature::hooks::logging::structured","provider_name":"No-op Provider","target":"open_feature","timestamp":1736537120828}
```

--------------------------------

### Fetch Welcome Resource with curl

Source: https://openfeature.dev/docs/tutorials/getting-started/java/dropwizard

Use curl to make a request to the /welcome endpoint and observe the default response.

```bash
$ curl -i http://localhost:8080/welcome
```

--------------------------------

### Basic OpenFeature Usage

Source: https://openfeature.dev/docs/reference/sdks/server/php

Demonstrates initializing the API, setting a provider, and retrieving a boolean flag value.

```php
use OpenFeature\OpenFeatureAPI;  

use OpenFeature\Providers\Flagd\FlagdProvider;  

  

function example()  

{  

    $api = OpenFeatureAPI::getInstance();  

      

    // configure a provider  

    $api->setProvider(new FlagdProvider());  

  

    // create a client  

    $client = $api->getClient();  

  

    // get a bool flag value  

    $client->getBooleanValue('v2_enabled', false);  

}  
```

--------------------------------

### Migration Example with Multi-Provider

Source: https://openfeature.dev/docs/reference/sdks/server/javascript

Implement a migration strategy using Multi-Provider, serving flags from a new provider first and falling back to an old one. Uses FirstMatchStrategy for sequential evaluation.

```javascript
import { OpenFeature, MultiProvider, FirstMatchStrategy } from '@openfeature/server-sdk';  

// During migration, serve some flags from the new provider and fallback to the old one  
const newProvider = new NewFlagProvider();  
const oldProvider = new OldFlagProvider();  

const multiProvider = new MultiProvider(  
  [{ provider: newProvider }, { provider: oldProvider }], // New provider is consulted first  

  new FirstMatchStrategy(),  
);

await OpenFeature.setProviderAndWait(multiProvider);  
```

--------------------------------

### Build and Run the Application

Source: https://openfeature.dev/docs/tutorials/getting-started/dotnet

Compiles and runs the .NET application after adding dependencies and code. Use this to test your OpenFeature integration.

```bash
dotnet build

dotnet run
```

--------------------------------

### Install CocoaPods Dependencies

Source: https://openfeature.dev/docs/reference/sdks/client/swift

Run this command after updating your Podfile to install the specified CocoaPods dependencies.

```bash
pod install  
```

--------------------------------

### Install OpenFeature MCP

Source: https://openfeature.dev/docs/reference/sdks/client/swift

Use this command to install the OpenFeature MCP with the specified transport and package.

```bash
claude mcp add --transport stdio openfeature npx -y @openfeature/mcp  
```

--------------------------------

### iOS SDK Basic Usage

Source: https://openfeature.dev/docs/reference/sdks/client/swift

Demonstrates basic iOS SDK usage: setting a provider and evaluating a boolean flag. Ensure the provider is configured and initialized before use.

```swift
import OpenFeature  
  
Task {  
    let provider = CustomProvider()  

    // configure a provider, wait for it to complete its initialization tasks  
    await OpenFeatureAPI.shared.setProviderAndWait(provider: provider)  

    // get a bool flag value  
    let client = OpenFeatureAPI.shared.getClient()  
    let flagValue = client.getBooleanValue(key: "boolFlag", defaultValue: false)  
}  
```

--------------------------------

### Build and Run Dropwizard Application

Source: https://openfeature.dev/docs/tutorials/getting-started/java/dropwizard

Compile the application using Maven and then run the generated JAR file with a configuration file. Observe the startup logs for server details.

```bash
$ mvn clean package  

$ java -jar target/openfeature-example-1.0-SNAPSHOT.jar server config.yml  

INFO  [2025-06-13 10:00:00,000] io.dropwizard.core.server.DefaultServerFactory: Registering jersey handler with root path prefix: /  

INFO  [2025-06-13 10:00:00,000] io.dropwizard.core.server.DefaultServerFactory: Registering admin handler with root path prefix: /  

INFO  [2025-06-13 10:00:00,000] io.dropwizard.core.server.ServerFactory: Starting OpenFeatureExample  

================================================================================  

  

                              OpenFeatureExample  

  

================================================================================  

  

INFO  [2025-06-13 10:00:00,000] org.eclipse.jetty.setuid.SetUIDListener: Opened application@748e9b20{HTTP/1.1, (http/1.1)}{0.0.0.0:8080}  

INFO  [2025-06-13 10:00:00,000] org.eclipse.jetty.setuid.SetUIDListener: Opened admin@2063c53e{HTTP/1.1, (http/1.1)}{0.0.0.0:8081}  

INFO  [2025-06-13 10:00:00,000] org.eclipse.jetty.server.Server: jetty-11.0.25; built: 2025-03-13T00:15:57.301Z; git: a2e9fae3ad8320f2a713d4fa29bba356a99d1295; jvm 21+35  

  

INFO  [2025-06-13 10:00:00,000] io.dropwizard.jersey.DropwizardResourceConfig: The following paths were found for the configured resources:  

  

    GET     /welcome (com.sideshowcoder.resources.WelcomeResource)  

...  
```

--------------------------------

### MultiProvider Error Aggregation Examples

Source: https://openfeature.dev/docs/reference/sdks/server/php

Examples showing how MultiProvider aggregates errors from multiple providers when evaluation fails.

```php
// Example: FirstMatchStrategy with all FLAG_NOT_FOUND  

$result = $client->getBooleanDetails('non-existent-flag', false);  

// Returns: value=false, reason=ERROR,   

// error="Multi-provider evaluation failed with 3 provider error(s): [ProviderA]: Flag not found; [ProviderB]: Flag not found; [ProviderC]: Flag not found"

// Example: ComparisonStrategy with provider errors  

$result = $client->getBooleanDetails('some-flag', false);  

// Returns: value=false, reason=ERROR,   

// error="Multi-provider evaluation failed with 2 provider error(s): [ProviderA]: Connection timeout; [ProviderB]: Invalid configuration"
```

--------------------------------

### Install OpenFeature MCP server

Source: https://openfeature.dev/docs/reference/sdks/server/java

Command to install the OpenFeature MCP server using the Claude MCP CLI.

```bash
claude mcp add --transport stdio openfeature npx -y @openfeature/mcp
```

--------------------------------

### Install flagd Provider

Source: https://openfeature.dev/docs/tutorials/getting-started/node

Install the flagd provider package using NPM. This makes the provider available for use in your Node.js application.

```bash
npm install @openfeature/flagd-provider
```

--------------------------------

### Install OpenFeature CLI via curl

Source: https://openfeature.dev/docs/reference/other-technologies/cli

Installs the OpenFeature CLI using a shell command, suitable for Unix-like operating systems.

```bash
curl -fsSL https://openfeature.dev/scripts/install_cli.sh | sh  
```

--------------------------------

### Build and Run .NET Application

Source: https://openfeature.dev/docs/tutorials/getting-started/dotnet

Compile and execute the .NET application using the .NET CLI.

```bash
dotnet build
dotnet run
```

--------------------------------

### Create Express App (JavaScript)

Source: https://openfeature.dev/docs/tutorials/getting-started/node

Set up a basic Express server in JavaScript.

```javascript
const express = require('express');

const app = express();
const port = 8080;

app.get('/', (_, res) => {
  res.send('Express + TypeScript Server');
});

app.listen(port, () => {
  console.log(`⚡️[server]: Server is running at http://localhost:${port}`);
});
```

--------------------------------

### Initialize and Use OpenFeature C++ SDK

Source: https://openfeature.dev/docs/reference/sdks/server/cpp

Demonstrates how to configure an in-memory provider, set it on the OpenFeature API, and retrieve a boolean flag value using a client. Requires C++17 or newer.

```cpp
void example() {
  // flags defined in memory
  std::unordered_map<std::string, std::any> my_flags = {
      {"v2_enabled", true}
  };
  // configure a provider
  openfeature::OpenFeatureAPI& api = openfeature::OpenFeatureAPI::GetInstance();
  api.SetProviderAndWait(std::make_shared<openfeature::InMemoryProvider>(my_flags));
  // create a client
  std::shared_ptr<openfeature::Client> client = api.GetClient();
  // get a bool flag value
  bool flag_value = client->GetBooleanValue("v2_enabled", false);
}
```

--------------------------------

### NPM Global Install for OpenFeature MCP Server

Source: https://openfeature.dev/docs/reference/other-technologies/mcp

Install the MCP server globally using NPM. This makes the `openfeature-mcp` command available system-wide.

```bash
npm install -g @openfeature/mcp
```

--------------------------------

### Set Up MultiProvider with Default Strategy

Source: https://openfeature.dev/docs/reference/sdks/client/swift

Initializes and sets a MultiProvider globally, combining primary and fallback providers using the default FirstMatchStrategy. This requires an asynchronous task to ensure the provider is set before use.

```swift
import OpenFeature  
  
Task {  
  
    // Create individual providers  

    let primaryProvider = PrimaryProvider()  

    let fallbackProvider = FallbackProvider()  
  
    // Create a MultiProvider with default FirstMatchStrategy  

    let multiProvider = MultiProvider(providers: [primaryProvider, fallbackProvider])  
  
    // Set the MultiProvider as the global provider  

    await OpenFeatureAPI.shared.setProviderAndWait(provider: multiProvider)  
  
    // Use flags normally - the MultiProvider will handle provider selection  

    let client = OpenFeatureAPI.shared.getClient()  

    let flagValue = client.getBooleanValue(key: "my-flag", defaultValue: false)  

}  
```

--------------------------------

### Provider Registration

Source: https://openfeature.dev/docs/reference/sdks/server/ruby

Register a provider with OpenFeature. The example shows registering an InMemoryProvider.

```APIDOC
OpenFeature::SDK.configure do |config|
  config.set_provider(OpenFeature::SDK::Provider::InMemoryProvider.new({
    "v2_enabled" => true
  }))
end
```

--------------------------------

### Add OpenFeature to requirements.txt

Source: https://openfeature.dev/docs/reference/sdks/server/python

Dependency declaration and installation command for requirements files.

```text
openfeature-sdk==0.10.0
```

```bash
pip install -r requirements.txt
```

--------------------------------

### Initialize and use OpenFeature client

Source: https://openfeature.dev/docs/reference/sdks/server/java

Demonstrates configuring an InMemoryProvider and evaluating a boolean flag using the OpenFeature API.

```java
public void example(){  

  

    // flags defined in memory  

    Map<String, Flag<?>> myFlags = new HashMap<>();  

    myFlags.put("v2_enabled", Flag.builder()  

        .variant("on", true)  

        .variant("off", false)  

        .defaultVariant("on")  

        .build());  

  

    // configure a provider  

    OpenFeatureAPI api = OpenFeatureAPI.getInstance();  

    try {  

        api.setProviderAndWait(new InMemoryProvider(myFlags));  

    } catch (Exception e) {  

        // handle initialization failure  

        e.printStackTrace();  

    }  

  

    // create a client  

    Client client = api.getClient();  

  

    // get a bool flag value  

    boolean flagValue = client.getBooleanValue("v2_enabled", false);  

}
```

--------------------------------

### Get OpenFeature Client

Source: https://openfeature.dev/docs/tutorials/getting-started/node

Obtain an OpenFeature client instance after importing the SDK.

```javascript
const port = 8080;
const client = OpenFeature.getClient();
```

--------------------------------

### Run Express App (TypeScript)

Source: https://openfeature.dev/docs/tutorials/getting-started/node

Start the Express server using ts-node.

```bash
npx ts-node index.ts
```
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