erl_web_push

Web push library in Erlang. Provides helpers for encrypting (RFC-8188) messages, preparing requests (RFC-8291) and opting in to VAPID (RFC-8292).

Installation

erl_web_push is published on hex.pm.

Configuration

In order to leverage VAPID, certain configuration keys have to be set:

• vapid_public_key: A base64 (optionally url-safe) encoded P256 public key.

  The public key is communicated through the k parameter of the authorization header, returned by vapid_request/{2,3}

• vapid_private_key: Corresponding base64 (optionally url-safe) encoded P256 private key.

  Used to sign the JWT token, communicated through the t parameter of the authorization header, returned by vapid_request/{2,3}

• vapid_contact: Either a mailto: (email) or https: URI where push providers can contact you

• json_encode: An {M, F} or {M, F, A} tuple describing a function to encode json.

  When {M, F} is provided, erl_web_push will call M:F(Map) (where Map is some JSON to encode). When {M, F, A} is provided, A is expected to be a list of arguments, which will follow Map. In other words, expect evaluation equivalent to apply(M, F, [Map | A]).

These keys are expected to be found as configuration parameters in the erl_web_application. Accordingly, add a section like so to your sys.config or otherwise ensure these configuration parameters can be retrieved.

[ ...
, {erl_web_push, [ {vapid_public_key, <<...>>}
                 , {vapid_private_key, <<...>>}
                 , ...
                 ]}
].

Calling erl_web_push:generate_vapid_keys() will generate a keypair, returning it as a formatted list of tuples which can be used in sys.config.