# PHP SDK Reference

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[ConfigCat PHP SDK on GitHub](https://github.com/configcat/php-sdk)

## Getting started[​](#getting-started "Direct link to Getting started")

### 1. Install the package with [Composer](https://getcomposer.org/)[​](#1-install-the-package-with-composer "Direct link to 1-install-the-package-with-composer")

```bash
composer require configcat/configcat-client

```

### 2. Create the *ConfigCat* client with your *SDK Key*[​](#2-create-the-configcat-client-with-your-sdk-key "Direct link to 2-create-the-configcat-client-with-your-sdk-key")

```php
$client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
  \ConfigCat\ClientOptions::CACHE => new \ConfigCat\Cache\LaravelCache(\Illuminate\Support\Facades\Cache::store()),
]);

```

warning

Due to the nature of PHP, for each HTTP request, it spawns a dedicated PHP process that will instantiate a new ConfigCat client every time. Therefore, to avoid the download of all feature flag data at every initialization, it's crucial to set up appropriate caching.

For more caching options, see the [Cache](#cache) section of this documentation.

### 3. Get your setting value[​](#3-get-your-setting-value "Direct link to 3. Get your setting value")

```php
$isMyAwesomeFeatureEnabled = $client->getValue("isMyAwesomeFeatureEnabled", false);
if (is_bool($isMyAwesomeFeatureEnabled) && $isMyAwesomeFeatureEnabled) {
    doTheNewThing();
} else {
    doTheOldThing();
}

```

## Creating the *ConfigCat Client*[​](#creating-the-configcat-client "Direct link to creating-the-configcat-client")

*ConfigCat Client* is responsible for:

* managing the communication between your application and ConfigCat servers.
* caching your setting values and feature flags.
* serving values quickly in a failsafe way.

Constructor parameters:

| Name      | Type     | Description                                                                                       |
| --------- | -------- | ------------------------------------------------------------------------------------------------- |
| `sdkKey`  | `string` | **REQUIRED.** SDK Key to access your feature flag and setting. Get it from *ConfigCat Dashboard*. |
| `options` | `array`  | **Optional.** Additional SDK options, see below for the detailed list.                            |

Available options:

| Name                     | Type                                                                                                                         | Description                                                                                                                                                                                                                                                                                                                                                                         |
| ------------------------ | ---------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `data-governance`        | `int`                                                                                                                        | Optional, defaults to `DataGovernance::GLOBAL_`. Describes the location of your feature flag and setting data within the ConfigCat CDN. This parameter needs to be in sync with your Data Governance preferences. [More about Data Governance](https://configcat.com/docs/advanced/data-governance.md). Available options: `GLOBAL_`, `EU_ONLY`.                                    |
| `logger`                 | [`\Psr\Log\LoggerInterface`](https://github.com/php-fig/log/blob/master/src/LoggerInterface.php)                             | Optional, sets the logger for errors and warnings produced by the SDK, defaults to [Monolog](https://github.com/Seldaek/monolog). [More about logging](#logging).                                                                                                                                                                                                                   |
| `log-level`              | `int`                                                                                                                        | Optional, defaults to `LogLevel::WARNING`. Sets the internal log level. [More about log levels](#logging).                                                                                                                                                                                                                                                                          |
| `cache`                  | [`\ConfigCat\Cache\ConfigCache`](https://github.com/configcat/php-sdk/blob/master/src/Cache/ConfigCache.php)                 | Optional, sets a `\ConfigCat\Cache\ConfigCache` implementation for caching the latest feature flag and setting values. [More about cache](#cache). You can check the currently available implementations [here](https://github.com/configcat/php-sdk/tree/master/src/Cache).                                                                                                        |
| `cache-refresh-interval` | `int`                                                                                                                        | Optional, sets the refresh interval of the cache in seconds, after the initial cached value is set this value will be used to determine how much time must pass before initiating a [config JSON download](https://configcat.com/docs/requests.md). Defaults to 60.                                                                                                                 |
| `request-options`        | `array`                                                                                                                      | *(Deprecated)* Optional, sets the request options (e.g. [HTTP Timeout](#http-timeout), [HTTP Proxy](#http-proxy)) for the underlying `Guzzle` HTTP client used for [downloading the config JSON](https://configcat.com/docs/requests.md) files. See Guzzle's [official documentation](https://docs.guzzlephp.org/en/stable/request-options.html) for the available request options. |
| `fetch-client`           | [`\ConfigCat\Http\FetchClientInterface`](https://github.com/configcat/php-sdk/blob/master/src/Http/FetchClientInterface.php) | Custom fetch client that wraps an actual HTTP client used to make HTTP requests towards ConfigCat. When it's not set, [`\ConfigCat\Http\GuzzleFetchClient`](https://github.com/configcat/php-sdk/blob/master/src/Http/GuzzleFetchClient.php) is used by default.                                                                                                                    |
| `flag-overrides`         | [`\ConfigCat\Override\FlagOverrides`](https://github.com/configcat/php-sdk/blob/master/src/Override/FlagOverrides.php)       | Optional, sets the local feature flag & setting overrides. [More about feature flag overrides](#flag-overrides).                                                                                                                                                                                                                                                                    |
| `exceptions-to-ignore`   | `array`                                                                                                                      | Optional, sets an array of exception classes that should be ignored from logs.                                                                                                                                                                                                                                                                                                      |
| `base-url`               | `string`                                                                                                                     | Optional, sets the CDN base url (forward proxy, dedicated subscription) from where the SDK will download the feature flags and settings.                                                                                                                                                                                                                                            |
| `default-user`           | [`\ConfigCat\User`](https://github.com/configcat/php-sdk/blob/master/src/User.php)                                           | Optional, sets the default user. [More about default user](#default-user).                                                                                                                                                                                                                                                                                                          |
| `offline`                | `bool`                                                                                                                       | Optional, defaults to `false`. Indicates whether the SDK should be initialized in offline mode. [More about offline mode](#online--offline-mode).                                                                                                                                                                                                                                   |

info

Each option name is available through constants of the [\ConfigCat\ClientOptions](https://github.com/configcat/php-sdk/blob/master/src/ClientOptions.php) class.

Example:

```php
$client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
    \ConfigCat\ClientOptions::CACHE => new \ConfigCat\Cache\LaravelCache(Cache::store()),
    \ConfigCat\ClientOptions::CACHE_REFRESH_INTERVAL => 5
]);

```

## Anatomy of `getValue()`[​](#anatomy-of-getvalue "Direct link to anatomy-of-getvalue")

| Parameters     | Description                                                                                                                                       |
| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- |
| `key`          | **REQUIRED.** Setting-specific key. Set on *ConfigCat Dashboard* for each setting.                                                                |
| `defaultValue` | **REQUIRED.** This value will be returned in case of an error.                                                                                    |
| `user`         | Optional, *User Object*. Essential when using Targeting. [Read more about Targeting.](https://configcat.com/docs/targeting/targeting-overview.md) |

```php
$value = $client->getValue(
    "keyOfMySetting", # Setting Key
    false, # Default value
    new \ConfigCat\User('#UNIQUE-USER-IDENTIFIER#') # Optional User Object
);

```

## Anatomy of `getValueDetails()`[​](#anatomy-of-getvaluedetails "Direct link to anatomy-of-getvaluedetails")

`getValueDetails()` is similar to `getValue()` but instead of returning the evaluated value only, it gives more detailed information about the evaluation result.

| Parameters     | Description                                                                                                                                       |
| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- |
| `key`          | **REQUIRED.** The key of a specific setting or feature flag. Set on *ConfigCat Dashboard* for each setting.                                       |
| `defaultValue` | **REQUIRED.** This value will be returned in case of an error.                                                                                    |
| `user`         | Optional, *User Object*. Essential when using Targeting. [Read more about Targeting.](https://configcat.com/docs/targeting/targeting-overview.md) |

```php
$details = $client->getValueDetails(
    "keyOfMySetting", # Setting Key
    false, # Default value
    new \ConfigCat\User('#UNIQUE-USER-IDENTIFIER#') # Optional User Object
);

```

The `details` result contains the following information:

| Property                         | Type                                 | Description                                                                                                |
| -------------------------------- | ------------------------------------ | ---------------------------------------------------------------------------------------------------------- |
| `getKey()`                       | `string`                             | The key of the evaluated feature flag or setting.                                                          |
| `getValue()`                     | `bool` / `string` / `int` / `double` | The evaluated value of the feature flag or setting.                                                        |
| `getUser()`                      | `?\ConfigCat\User`                   | The User Object used for the evaluation.                                                                   |
| `isDefaultValue()`               | `bool`                               | True when the default value passed to `getValueDetails()` is returned due to an error.                     |
| `getErrorMessage()`              | `?string`                            | In case of an error, this property contains the error message.                                             |
| `getErrorException()`            | `?Throwable`                         | In case of an error, this property contains the related exception object (if any).                         |
| `getMatchedTargetingRule()`      | `?array`                             | The Targeting Rule (if any) that matched during the evaluation and was used to return the evaluated value. |
| `getMatchedPercentageOption()`   | `?array`                             | The Percentage Option (if any) that was used to select the evaluated value.                                |
| `getFetchTimeUnixMilliseconds()` | `float`                              | The last download time of the current config in unix milliseconds format.                                  |

## User Object[​](#user-object "Direct link to User Object")

The [User Object](https://configcat.com/docs/targeting/user-object.md) is essential if you'd like to use ConfigCat's [Targeting](https://configcat.com/docs/targeting/targeting-overview.md) feature.

```php
$user = new \ConfigCat\User("#UNIQUE-USER-IDENTIFIER#");

```

```php
$user = new \ConfigCat\User("john@example.com");

```

### Customized User Object creation[​](#customized-user-object-creation "Direct link to Customized User Object creation")

| Parameters   | Description                                                                                                                                                                                                                                                        |
| ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `identifier` | **REQUIRED.** Unique identifier of a user in your application. Can be any `string` value, even an email address.                                                                                                                                                   |
| `email`      | Optional parameter for easier Targeting Rule definitions.                                                                                                                                                                                                          |
| `country`    | Optional parameter for easier Targeting Rule definitions.                                                                                                                                                                                                          |
| `custom`     | Optional associative array representing the custom attributes of a user for advanced Targeting Rule definitions. e.g. User role, Subscription type. The value's type of the array must be a `string`, `int`, `float`, `DateTimeInterface` or an array of `string`. |

```php
$user = new \ConfigCat\User(
    '#UNIQUE-USER-IDENTIFIER#',
    'john@example',
    'United Kingdom',
    [
        'SubscriptionType' => 'Pro',
        'UserRole' => 'Admin'
    ]);

```

caution

If you want to use a `string` value containing non-ASCII characters as a user attribute, please make sure that the content of the string is a UTF-8 byte sequence. ([A PHP string is just a sequence of bytes](https://www.php.net/manual/en/language.types.string.php), it doesn't use any internal character encoding, that is, doesn't offer native Unicode support. Thus, to support Unicode text, the ConfigCat SDK assumes UTF-8 encoding.)

The `custom` array also allows attribute values other than `string` values:

```php
$user = new \ConfigCat\User(
    '#UNIQUE-USER-IDENTIFIER#',
    null,
    null,
    [
        'Rating' => 4.5,
        'RegisteredAt' => new DateTimeImmutable('2023-11-22T12:34:56.0000000Z'),
        'Roles' => ['Role1', 'Role2']
    ]);

```

### User Object Attribute Types[​](#user-object-attribute-types "Direct link to User Object Attribute Types")

All comparators support `string` values as User Object attribute (in some cases they need to be provided in a specific format though, see below), but some of them also support other types of values. It depends on the comparator how the values will be handled. The following rules apply:

**Text-based comparators** (EQUALS, IS ONE OF, etc.)

* accept `string` values,
* all other values are automatically converted to `string` (a warning will be logged but evaluation will continue as normal).

**SemVer-based comparators** (IS ONE OF, <, >=, etc.)

* accept `string` values containing a properly formatted, valid semver value,
* all other values are considered invalid (a warning will be logged and the currently evaluated Targeting Rule will be skipped).

**Number-based comparators** (=, <, >=, etc.)

* accept `int` or `float` values,
* accept `string` values containing a properly formatted, valid `int` or `float` value,
* all other values are considered invalid (a warning will be logged and the currently evaluated Targeting Rule will be skipped).

**Date time-based comparators** (BEFORE / AFTER)

* accept `DateTimeInterface` values, which are automatically converted to a second-based Unix timestamp,
* accept `int` or `float` values representing a second-based Unix timestamp,
* accept `string` values containing a properly formatted, valid `int` or `float` value,
* all other values are considered invalid (a warning will be logged and the currently evaluated Targeting Rule will be skipped).

**String array-based comparators** (ARRAY CONTAINS ANY OF / ARRAY NOT CONTAINS ANY OF)

* accept arrays of `string`,
* accept `string` values containing a valid JSON string which can be deserialized to an array of `string`,
* all other values are considered invalid (a warning will be logged and the currently evaluated Targeting Rule will be skipped).

### Default user[​](#default-user "Direct link to Default user")

There's an option to set a default User Object that will be used at feature flag and setting evaluation. It can be useful when your application has a single user only, or rarely switches users.

You can set the default User Object either on SDK initialization:

```php
$client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
    \ConfigCat\ClientOptions::DEFAULT_USER => new \ConfigCat\User("john@example.com"),
]);

```

or with the `setDefaultUser()` method of the ConfigCat client.

```php
$client->setDefaultUser(new \ConfigCat\User("john@example.com"));

```

Whenever the `getValue()`, `getValueDetails()`, `getAllValues()`, or `getAllVariationIds()` methods are called without an explicit `user` parameter, the SDK will automatically use the default user as a User Object.

```php
$user = new \ConfigCat\User("john@example.com");
$client->setDefaultUser($user);

// The default user will be used at the evaluation process.
$value = $client->getValue("keyOfMySetting", false);

```

When the `user` parameter is specified on the requesting method, it takes precedence over the default user.

```php
$user = new \ConfigCat\User("john@example.com");
$client->setDefaultUser($user);

$otherUser = new \ConfigCat\User("brian@example.com");

// $otherUser will be used at the evaluation process.
$value = $client->getValue("keyOfMySetting", false, $otherUser);

```

For deleting the default user, you can do the following:

```php
$client->clearDefaultUser();

```

## `getAllKeys()`[​](#getallkeys "Direct link to getallkeys")

You can get the keys for all available feature flags and settings by calling the `getAllKeys()` method.

```php
$client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#");
$keys = $client->getAllKeys();

```

## `getAllValues()`[​](#getallvalues "Direct link to getallvalues")

Evaluates and returns the values of all feature flags and settings. Passing a User Object is optional.

```php
$client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#");
$settingValues = $client->getAllValues();

// invoke with User Object
$user = new \ConfigCat\User("john@example.com");
$settingValuesTargeting = $client->getAllValues($user);

```

## Hooks[​](#hooks "Direct link to Hooks")

The SDK provides several hooks (events), by means of which you can get notified of its actions. You can subscribe to the following events emitted by the *ConfigCat* client:

* `onConfigChanged([key => setting])`: This event is emitted first when the client's internal cache gets populated. Afterwards, it is emitted again each time the internally cached config is updated to a newer version, either as a result of synchronization with the external cache, or as a result of fetching a newer version from the ConfigCat CDN.
* `onFlagEvaluated(EvaluationDetails)`: This event is emitted each time the client evaluates a feature flag or setting. The event provides the same evaluation details that you would get from [`getValueDetails()`](#anatomy-of-getvaluedetails).
* `onError(string)`: This event is emitted when an error occurs within the client.

You can subscribe to these events with the `hooks` property of the ConfigCat client:

```php
$client->hooks()->addOnFlagEvaluated(function (EvaluationDetails $details) {
    /* handle the event */
});

```

## Online / Offline mode[​](#online--offline-mode "Direct link to Online / Offline mode")

In cases when you'd want to prevent the SDK from making HTTP calls, you can put it in offline mode:

```php
$client->setOffline();

```

In offline mode, the SDK won't initiate HTTP requests and will work only from its cache.

To put the SDK back in online mode, you can do the following:

```php
$client->setOnline();

```

> With `$client->isOffline()` you can check whether the SDK is in offline mode.

## Flag Overrides[​](#flag-overrides "Direct link to Flag Overrides")

With flag overrides you can overwrite the feature flags & settings downloaded from the ConfigCat CDN with local values. Moreover, you can specify how the overrides should apply over the downloaded values. The following 3 behaviours are supported:

* **Local only** (`OverrideBehaviour::LOCAL_ONLY`): When evaluating values, the SDK will not use feature flags & settings from the ConfigCat CDN, but it will use all feature flags & settings that are loaded from local-override sources.

* **Local over remote** (`OverrideBehaviour::LOCAL_OVER_REMOTE`): When evaluating values, the SDK will use all feature flags & settings that are downloaded from the ConfigCat CDN, plus all feature flags & settings that are loaded from local-override sources. If a feature flag or a setting is defined both in the downloaded and the local-override source then the local-override version will take precedence.

* **Remote over local** (`OverrideBehaviour::REMOTE_OVER_LOCAL`): When evaluating values, the SDK will use all feature flags & settings that are downloaded from the ConfigCat CDN, plus all feature flags & settings that are loaded from local-override sources. If a feature flag or a setting is defined both in the downloaded and the local-override source then the downloaded version will take precedence.

You can load your feature flag & setting overrides from a file or from a simple associative array.

### JSON File[​](#json-file "Direct link to JSON File")

The SDK can be set up to load your feature flag & setting overrides from a file. You can also specify whether the file should be reloaded when it gets modified.

```php
$client = new \ConfigCat\ConfigCatClient("localhost", [
  \ConfigCat\ClientOptions::FLAG_OVERRIDES => new \ConfigCat\Override\FlagOverrides(
    \ConfigCat\Override\OverrideDataSource::localFile("path/to/the/local_flags.json"), // path to the file
    \ConfigCat\Override\OverrideBehaviour::LOCAL_ONLY
  ),
]);

```

#### JSON File Structure[​](#json-file-structure "Direct link to JSON File Structure")

The SDK supports 2 types of JSON structures to describe feature flags & settings.

##### 1. Simple (key-value) structure[​](#1-simple-key-value-structure "Direct link to 1. Simple (key-value) structure")

```json
{
  "flags": {
    "enabledFeature": true,
    "disabledFeature": false,
    "intSetting": 5,
    "doubleSetting": 3.14,
    "stringSetting": "test"
  }
}

```

##### 2. Complex (full-featured) structure[​](#2-complex-full-featured-structure "Direct link to 2. Complex (full-featured) structure")

This is the same format that the SDK downloads from the ConfigCat CDN. It allows the usage of all features that are available on the ConfigCat Dashboard.

You can download your current config JSON from ConfigCat's CDN and use it as a baseline.

The URL to your current config JSON is based on your [Data Governance](https://configcat.com/docs/advanced/data-governance.md) settings:

* GLOBAL: `https://cdn-global.configcat.com/configuration-files/{YOUR-SDK-KEY}/config_v6.json`
* EU: `https://cdn-eu.configcat.com/configuration-files/{YOUR-SDK-KEY}/config_v6.json`

```json
{
  "f": {
    // list of feature flags & settings
    "isFeatureEnabled": {
      // key of a particular flag
      "v": false, // default value, served when no rules are defined
      "i": "430bded3", // variation id (for analytical purposes)
      "t": 0, // feature flag's type, possible values:
      // 0 -> BOOLEAN
      // 1 -> STRING
      // 2 -> INT
      // 3 -> DOUBLE
      "p": [
        // list of percentage rules
        {
          "o": 0, // rule's order
          "v": true, // value served when the rule is selected during evaluation
          "p": 10, // % value
          "i": "bcfb84a7" // variation id (for analytical purposes)
        },
        {
          "o": 1, // rule's order
          "v": false, // value served when the rule is selected during evaluation
          "p": 90, // % value
          "i": "bddac6ae" // variation id (for analytical purposes)
        }
      ],
      "r": [
        // list of Targeting Rules
        {
          "o": 0, // rule's order
          "a": "Identifier", // comparison attribute
          "t": 2, // comparator, possible values:
          // 0  -> 'IS ONE OF',
          // 1  -> 'IS NOT ONE OF',
          // 2  -> 'CONTAINS',
          // 3  -> 'DOES NOT CONTAIN',
          // 4  -> 'IS ONE OF (SemVer)',
          // 5  -> 'IS NOT ONE OF (SemVer)',
          // 6  -> '< (SemVer)',
          // 7  -> '<= (SemVer)',
          // 8  -> '> (SemVer)',
          // 9  -> '>= (SemVer)',
          // 10 -> '= (Number)',
          // 11 -> '<> (Number)',
          // 12 -> '< (Number)',
          // 13 -> '<= (Number)',
          // 14 -> '> (Number)',
          // 15 -> '>= (Number)',
          // 16 -> 'IS ONE OF (Hashed)',
          // 17 -> 'IS NOT ONE OF Hashed)'
          "c": "@example.com", // comparison value
          "v": true, // value served when the rule is selected during evaluation
          "i": "bcfb84a7" // variation id (for analytical purposes)
        }
      ]
    }
  }
}

```

### Associative Array[​](#associative-array "Direct link to Associative Array")

You can set up the SDK to load your feature flag & setting overrides from an associative array.

```php
$client = new \ConfigCat\ConfigCatClient("localhost", [
  \ConfigCat\ClientOptions::FLAG_OVERRIDES => new \ConfigCat\Override\FlagOverrides(
    \ConfigCat\Override\OverrideDataSource::localArray([
      'enabledFeature' => true,
      'disabledFeature' => false,
      'intSetting' => 5,
      'doubleSetting' => 3.14,
      'stringSetting' => "test",
    ]), \ConfigCat\Override\OverrideBehaviour::LOCAL_ONLY),
]);

```

## Cache[​](#cache "Direct link to Cache")

You can use the following caching options:

* Laravel:

  ```php
  $client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
    \ConfigCat\ClientOptions::CACHE => new \ConfigCat\Cache\LaravelCache(\Illuminate\Support\Facades\Cache::store()),
  ]);

  ```

* PSR-6 cache (e.g. the [redis adapter](https://github.com/php-cache/redis-adapter) for PSR-6):

  ```php
  $client = new \RedisArray(['127.0.0.1:6379', '127.0.0.2:6379']);
  $pool = new RedisCachePool($client);

  $client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
    \ConfigCat\ClientOptions::CACHE => new \ConfigCat\Cache\Psr6Cache($pool),
  ]);

  ```

  or with the [file system adapter](https://github.com/php-cache/filesystem-adapter):

  ```php
  $filesystemAdapter = new \League\Flysystem\Adapter\Local(__DIR__.'/');
  $filesystem = new \League\Flysystem\Filesystem($filesystemAdapter);
  $pool = new \Cache\Adapter\Filesystem\FilesystemCachePool($filesystem);

  $client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
    \ConfigCat\ClientOptions::CACHE => new \ConfigCat\Cache\Psr6Cache($pool),
  ]);

  ```

* PSR-16 cache (e.g. the [redis adapter](https://github.com/php-cache/redis-adapter) for PSR-6 and the [PSR-6 to PSR-16 cache bridge](https://github.com/php-cache/simple-cache-bridge)):

  ```php
  $client = new \RedisArray(['127.0.0.1:6379', '127.0.0.2:6379']);
  $pool = new RedisCachePool($client);
  $simpleCache = new SimpleCacheBridge($pool);

  $client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
    \ConfigCat\ClientOptions::CACHE => new \ConfigCat\Cache\Psr16Cache($simpleCache),
  ]);

  ```

  or with the [file system adapter](https://github.com/php-cache/filesystem-adapter):

  ```php
  $filesystemAdapter = new \League\Flysystem\Adapter\Local(__DIR__.'/');
  $filesystem = new \League\Flysystem\Filesystem($filesystemAdapter);
  $pool = new \Cache\Adapter\Filesystem\FilesystemCachePool($filesystem);
  $simpleCache = new SimpleCacheBridge($pool);

  $client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
    \ConfigCat\ClientOptions::CACHE => new \ConfigCat\Cache\Psr16Cache($simpleCache),
  ]);

  ```

* Custom cache implementation

  ```php
  class CustomCache extends \ConfigCat\Cache\ConfigCache
  {
      protected function get(string $key): ?string
      {
          // load from cache
      }

      protected function set(string $key, string $value): void
      {
          // save into cache
      }
  }

  ```

info

The PHP SDK supports *shared caching*. You can read more about this feature and the required minimum SDK versions [here](https://configcat.com/docs/advanced/caching.md#shared-cache).

## Logging[​](#logging "Direct link to Logging")

The SDK uses the PSR-3 `LoggerInterface` for logging, so you can use any implementor package like [Monolog](https://github.com/Seldaek/monolog).

```php
$client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
    \ConfigCat\ClientOptions::LOGGER => new \Monolog\Logger("name"),
]);

```

You can change the verbosity of the logs by setting the `log-level` option.

```php
$client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
    \ConfigCat\ClientOptions::LOG_LEVEL => \ConfigCat\Log\LogLevel::INFO
]);

```

The following levels are used by the ConfigCat SDK:

| Level     | Description                                                                             |
| --------- | --------------------------------------------------------------------------------------- |
| `NO_LOG`  | Turn the logging off.                                                                   |
| `ERROR`   | Only error level events are logged.                                                     |
| `WARNING` | Default. Errors and Warnings are logged.                                                |
| `INFO`    | Errors, Warnings and feature flag evaluation is logged.                                 |
| `DEBUG`   | All of the above plus debug info is logged. Debug logs can be different for other SDKs. |

Info level logging helps to inspect how a feature flag was evaluated:

```bash
[2022-01-06T18:34:16.846039+00:00] ConfigCat.INFO: [5000] Evaluating 'isPOCFeatureEnabled' for User '{"Identifier":"<SOME USERID>","Email":"configcat@example.com","Country":"US","SubscriptionType":"Pro","Role":"Admin","version":"1.0.0"}'
  Evaluating targeting rules and applying the first match if any:
  - IF User.Email CONTAINS ANY OF ['@something.com'] THEN 'false' => no match
  - IF User.Email CONTAINS ANY OF ['@example.com'] THEN 'true' => MATCH, applying rule
  Returning 'true'.

```

## HTTP Client[​](#http-client "Direct link to HTTP Client")

The SDK by default uses [Guzzle](https://docs.guzzlephp.org/en/stable/index.html) for the underlying HTTP calls. The default HTTP client is customizable through the `\ConfigCat\Http\GuzzleFetchClient::create()` method at the SDK's initialization. To learn more about Guzzle's customization options see the [official documentaion](https://docs.guzzlephp.org/en/stable/request-options.html).

```php
$client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
     \ConfigCat\ClientOptions::FETCH_CLIENT => \ConfigCat\Http\GuzzleFetchClient::create([
         \GuzzleHttp\RequestOptions::CONNECT_TIMEOUT => 5,
     ]),
]);

```

Through the `\ConfigCat\ClientOptions::FETCH_CLIENT` option you can pass your own HTTP client by providing a `\ConfigCat\Http\FetchClientInterface` implementation.

```php
class CustomFetchClient implements \ConfigCat\Http\FetchClientInterface
{
    public function getClient(): \Psr\Http\Client\ClientInterface
    {
        // return with a \Psr\Http\Client\ClientInterface implementation.
    }

    public function createRequest(string $method, string $uri): \Psr\Http\Message\RequestInterface
    {
        // return with a \Psr\Http\Message\RequestInterface implementation
    }
}

```

```php
$client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
     \ConfigCat\ClientOptions::FETCH_CLIENT => new CustomFetchClient(),
]);

```

### HTTP Proxy[​](#http-proxy "Direct link to HTTP Proxy")

If your application runs behind a proxy you can do the following:

```php
$client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
    \ConfigCat\ClientOptions::REQUEST_OPTIONS => [
        \GuzzleHttp\RequestOptions::PROXY => [
            'http'  => 'tcp://localhost:8125',
            'https' => 'tcp://localhost:9124',
        ]
    ],
]);

```

### HTTP Timeout[​](#http-timeout "Direct link to HTTP Timeout")

You can set the maximum wait time for a ConfigCat HTTP response by using Guzzle's timeouts.

```php
$client = new \ConfigCat\ConfigCatClient("#YOUR-SDK-KEY#", [
    \ConfigCat\ClientOptions::REQUEST_OPTIONS => [
        \GuzzleHttp\RequestOptions::CONNECT_TIMEOUT => 5,
        \GuzzleHttp\RequestOptions::TIMEOUT => 10
    ],
]);

```

## Sample Applications[​](#sample-applications "Direct link to Sample Applications")

* [Sample Laravel App](https://github.com/configcat/php-sdk/tree/master/samples/laravel)

## Guides[​](#guides "Direct link to Guides")

See [this](https://configcat.com/blog/2022/09/16/how-to-use-feature-flags-in-php/) guide on how to use ConfigCat's PHP SDK.

## Look under the hood[​](#look-under-the-hood "Direct link to Look under the hood")

* [ConfigCat PHP SDK's repository on GitHub](https://github.com/configcat/php-sdk)
* [ConfigCat PHP SDK on packagist.org](https://packagist.org/packages/configcat/configcat-client)