# Firebase Token Generator - Erlang

Helper module for generating custom Firebase token in Erlang. Custom Firebase tokens are used on applications with totally different authentication methods. These tokens are in JWT (JSON Web Token) format and can be then used by client applications on authenticating to Firebase.

Only supports Firebase 3.x.x. See https://firebase.google.com/docs/auth/server/create-custom-tokens for more information.

## Setup

This can be added as a dependency from [hex.pm](https://hex.pm/packages/firebase_token)

```
{deps, [

  %% ... other dependencies

  {firebase_token, "1.0.0"}
]}. 
```

## Usage

One of the requirements for this library is the service account key JSON file that can be obtained from the [Google API Manager Console](https://console.developers.google.com/apis/credentials)

```erlang
Account = firebase_token:load_account("/path/to/service_account.json"),
Extra = #{
  %% Arbitrary values
  admin => true
},
{token, _FirebaseToken} = firebase_token:generate(Account, Uid, 3600, Extra).
```

> **NOTE**: Extras cannot have the following keys: **acr**, **amr**, **at_hash**, **aud**, **auth_time**, **azp**, **cnf**, **c_hash**, **exp**, **firebase**, **iat**, **iss**, **jti**, **nbf**, **nonce** and **sub**.