Configuration

VAPID support

To enable the VAPID header feature, you must install a JWS Provider (see installation) and configure it with your public and private key (see this page to create these keys)

config/packages/webpush.yaml

webpush:
  vapid:
    enabled: true # Enable the feature
    subject: 'https://my-service.com:8000' # An URL or an email address
    web_token:
      enabled: true # We use web-token in this example
      public_key: 'BB4W1qfBi7MF_Lnrc6i2oL-glAuKF4kevy9T0k2vyKV4qvuBrN3T6o9-7-NR3mKHwzDXzD3fe7XvIqIU1iADpGQ'
      private_key: 'C40jLFSa5UWxstkFvdwzT3eHONE2FIJSEsVIncSCAqU'

When using lcobucci/jwt, the configuration is very similar.

config/packages/webpush.yaml

webpush:
  vapid:
    enabled: true
    subject: 'https://my-service.com:8000'
    lcobucci:
      enabled: true # We use lcobucci/jwt in this example
      public_key: 'BB4W1qfBi7MF_Lnrc6i2oL-glAuKF4kevy9T0k2vyKV4qvuBrN3T6o9-7-NR3mKHwzDXzD3fe7XvIqIU1iADpGQ'
      private_key: 'C40jLFSa5UWxstkFvdwzT3eHONE2FIJSEsVIncSCAqU'

Danger

You cannot enable both web-token and lcobucci/jwt at the same time

Custom JWS provider

If you want to use a custom JWS Provider (not web-token or lcobucci/jwt), you can configure it as follows:

config/packages/webpush.yaml

webpush:
  vapid:
    enabled: true
    subject: 'https://my-service.com:8000'
    custom:
      enabled: true
      id: 'app.my_custom_jws_provider' # The service ID of your custom provider

Your custom provider must implement the WebPush\VAPID\JWSProvider interface.

Token lifetime

By default, the library generates VAPID headers that are valid for 1 hour. You can change this value if needed. The parameter requires a relative string as showed in the PHP documentation.

config/packages/webpush.yaml

webpush:
  vapid:
    enabled: true
    token_lifetime: 'now +2 hours'

Warning

The token lifetime should not be greater than 24 hours. Most of the Web Push Services will reject such long-life tokens

Payload support

Padding

To obfuscate the real length of the notifications, messages can be padded before encryption. This operation consists in the concatenation of your message and arbitrary data in front of it. When encrypted, the messages will have the same size which reduces attacks.

By default, the padding is set to recommended i.e. ~3k bytes.

Acceptable values for this parameter are:

• none: no padding
• recommended: default value
• max: see warning below
• an integer: should be between 0 and 4078 or 3993 for AESGCM and AES128GCM respectively

config/packages/webpush.yaml

webpush:
  payload:
    aesgcm:
      padding: 'none' # "none", "recommended", "max" or an integer (0 to 4078)
    aes128gcm:
      padding: 'none' # "none", "recommended", "max" or an integer (0 to 3993)

Danger

Please don't use "none" unless you are sending notifications in a development environment.

Warning

The value "max" increases the integrity protection of the messages, but there are known issues on Android and notifications are not correctly delivered.

Caching

The notifications may have a payload. This payload is encrypted on server side and, during this process, a random key is generated.

The creation of this random key takes approximately 150ms and can impact your server performance when sending thousand of notifications at once.

To reduce the impact on your server, you can enable the caching feature and reuse the encryption key for a defined period of time.

Danger

As encryption keys will be stored in the cache, you should make sure the cache is not shared otherwise you may have a security issue.

This parameter requires a PSR-6 Cache compatible service. If you set Psr\Log\CacheItemPoolInterface, the default Symfony cache will be used.

config/packages/webpush.yaml

webpush:
  payload:
    aesgcm:
      cache: Psr\Cache\CacheItemPoolInterface
      cache_lifetime: '+1 hour' #Default: now +30min
    aes128gcm:
      cache: Psr\Cache\CacheItemPoolInterface
      cache_lifetime: '+1 hour' #Default: now +30min

Success

You can see the impact of this feature on the CI/CD Pipelines of this library. Go the https://github.com/Spomky-Labs/web-push/actions?query=workflow%3ABenchmark and find a summary table displayed at the end of each test.

Debugging

If you have troubles sending notifications, you can log some messages from the library. To do so, you just have to set the parameter logger in the configuration.

This parameter requires a PSR-3 logger. If you set Psr\Log\LoggerInterface, the Symfony logger will be used (PSR-3 compatible).

config/packages/webpush.yaml

webpush:
  logger: Psr\Log\LoggerInterface