Configuration Overview

PHP Constants

Your web/index.php file can define certain PHP constants, which Craft’s bootstrap script will check for while loading and configuring Craft.

General Config Settings

Craft supports several general config settings. You can override their default values in your config/general.php file.

return [
    'devMode' => true, 
];

Database Connection Settings

Craft supports several database connection settings. You can override their default values in your config/db.php file.

Data Caching Config

By default, Craft will store data caches in the storage/runtime/cache/ folder. You can configure Craft to use an alternative cache storage by overriding the cache application component from config/app.php.

<?php
return [
    'components' => [
        'cache' => [
            'class' => yii\caching\ApcCache::class,
            'useApcu' => true,
        ],
    ],
];

Examples

Here are a couple common examples of cache storage configurations:

Memcached

<?php
return [
    'components' => [
        'cache' => [
            'class' => yii\caching\MemCache::class,
            'useMemcached' => true,
            'username' => getenv('MEMCACHED_USERNAME'),
            'password' => getenv('MEMCACHED_PASSWORD'),
            'defaultDuration' => 86400,
            'servers' => [
                [
                    'host' => 'localhost',
                    'persistent' => true,
                    'port' => 11211,
                    'retryInterval' => 15,
                    'status' => true,
                    'timeout' => 15,
                    'weight' => 1,
                ],
            ],
        ],
    ],
];

Redis

To use Redis cache storage, you will first need to install the yii2-redis library. Then configure Craft’s cache component to use it:

<?php
return [
    'components' => [
        'cache' => [
            'class' => yii\redis\Cache::class,
            'defaultDuration' => 86400,
            'redis' => [
                'hostname' => 'localhost',
                'port' => 6379,
                'password' => getenv('REDIS_PASSWORD'),
                'database' => 0,
            ],
        ],
    ],
];

Guzzle Config

Craft uses Guzzle 6 whenever creating HTTP requests, such as:

  • when checking for Craft updates
  • when sending in a support request from the Craft Support widget
  • when loading RSS feeds from the Feeds widget
  • when working with assets on remote volumes, like Amazon S3

You can customize the config settings Guzzle uses when sending these requests by creating a guzzle.php file in your config/ folder. The file should return an array, with your config overrides.

<?php

return [
    'headers' => ['Foo' => 'Bar'],
    'query'   => ['testing' => '123'],
    'auth'    => ['username', 'password'],
    'proxy'   => 'tcp://localhost:80',
];

The options defined here will be passed into new GuzzleHttp\Client instances. See Guzzle’s documentation for a list of available options.

Aliases

Some settings and functions in Craft support Yii aliases, which are basically placeholders for base file system paths and URLs. These include:

The following aliases are available out of the box:

AliasDescription
@appThe path to vendor/craftcms/cms/src/
@configThe path to your config/ folder
@contentMigrationsThe path to your migrations/ folder
@craftThe path to vendor/craftcms/cms/src/
@libThe path to vendor/craftcms/cms/lib/
@rootThe root project path (same as the CRAFT_BASE_PATH PHP constant)
@runtimeThe path to your storage/runtime/ folder
@storageThe path to your storage/ folder
@templatesThe path to your templates/ folder
@translationsThe path to your translations/ folder
@vendorThe path to your vendor/ folder
@webThe URL to the folder that contains the index.php file that was loaded for the request
@webrootThe path to the folder that contains the index.php file that was loaded for the request

You can define additional custom aliases using the aliases config setting. For example, you may wish to create aliases that define the base URL and base path that your asset volumes will live in.

'aliases' => [
    '@assetBaseUrl' => 'http://my-project.com/assets',
    '@assetBasePath' => '/path/to/web/assets',
],

With those in place, you could begin your asset volumes’ Base URL and File System Path settings with them, e.g. @assetBaseUrl/user-photos and @assetBasePath/user-photos.

If you’d like, you can set the alias values with environment variables, either from your .env file or somewhere in your environment’s configuration:

ASSET_BASE_URL=http://my-project.com/assets
ASSET_BASE_PATH=/path/to/web/assets

Then you can pull them into the alias definitions using getenv():

'aliases' => [
    '@assetBaseUrl' => getenv('ASSET_BASE_URL'),
    '@assetBasePath' => getenv('ASSET_BASE_PATH'),
],

Overriding Volume Settings

If you would prefer to define volume settings with a config file, you can do that from config/volumes.php. The file should return an array whose keys map to your volume handles, and values are nested arrays that define the overridden setting values.

WARNING

You must create your volumes within the Control Panel before Craft will start checking config/volumes.php for overrides.

return [
    'siteAssets' => [
        'path' => getenv('ASSETS_BASE_PATH').'/site',
        'url' => getenv('ASSETS_BASE_URL').'/site',
    ],
    'companyLogos' => [
        'path' => getenv('ASSETS_BASE_PATH').'/logos',
        'url' => getenv('ASSETS_BASE_URL').'/logos',
    ],
];

URL Rules

You can define custom URL rules in config/routes.php. See Routing for more details.

Application Config

You can customize Craft’s entire application configuration from config/app.php. Any items returned by that array will get merged into the main application configuration array.

Mailer Component

To override the mailer component config (which is responsible for sending emails), do this in config/app.php:

<?php

return [
    'components' => [
        'mailer' => function() {
            // Get the stored email settings
            $settings = Craft::$app->systemSettings->getEmailSettings();

            // Override the transport adapter class
            $settings->transportType = craft\mailgun\MailgunAdapter::class;

            // Override the transport adapter settings
            $settings->transportSettings = [
                'domain' => 'foo.com',
                'apiKey' => 'key-xxxxxxxxxx',
            ];

            return craft\helpers\MailerHelper::createMailer($settings);
        },

        // ...
    ],

    // ...
];

Queue Component

Craft’s job queue is powered by the Yii2 Queue Extension. By default Craft will use a custom queue driver based on the extension’s DB driver, but you can switch to a different driver by overriding Craft’s queue component from config/app.php:

<?php

return [
    'components' => [
        'queue' => [
            'class' => \yii\queue\redis\Queue::class,
            'redis' => 'redis', // Redis connection component or its config
            'channel' => 'queue', // Queue channel key
        ], 
    ],
    
    // ...
];

Available drivers are listed in the Yii2 Queue Extension documentation.

WARNING

Only drivers that implement craft\queue\QueueInterface will be visible within the Control Panel.

TIP

If your queue driver supplies its own worker, set the runQueueAutomatically config setting to false in config/general.php.