Upstream Firebase User Auth

This policy adds a Firebase Admin token to the outgoing Authentication header allowing requests to Firebase using Service Account admin permissions. This can be useful for calling Firebase services such as Firestore through a Zuplo endpoint that is secured with other means of Authentication such as API keys. Additionally, this policy can be useful for service content to all API users (for example serving a specific Firestore document containing configuration data)

We recommend reading the serviceAccountJson from environment variables (so it is not checked in to source control) using the $env(ENV_VAR) syntax.

Configuration

The configuration shows how to configure the policy in the 'policies.json' document.

{
  "name": "my-upstream-firebase-user-auth-inbound-policy",
  "policyType": "upstream-firebase-user-auth-inbound",
  "handler": {
    "export": "UpstreamFirebaseUserAuthInboundPolicy",
    "module": "$import(@zuplo/runtime)",
    "options": {
      "developerClaims": {
        "premium": true
      },
      "expirationOffsetSeconds": 300,
      "serviceAccountJson": "$env(SERVICE_ACCOUNT_JSON)",
      "tokenRetries": 3,
      "userId": "1234",
      "webApiKey": "$env(WEB_API_KEY)"
    }
  }
}

Policy Options

The options for this policy are specified below. All properties are optional unless specifically marked as required.

serviceAccountJson <string> (Required) -
The Google Service Account key in JSON format. Note you can load this from environment variables using the $env(ENV_VAR) syntax.
userId <string> -
The userId to use as the custom token's subject.
userIdPropertyPath <string> -
The property on the incoming request.user object to retrieve the value of the userId.
developerClaims <object> -
Additional claims to include in the custom token's payload.
webApiKey <string> (Required) -
The Firebase Web API Key (found in project settings)
tokenRetries <number> -
The number of times to retry fetching the token in the event of a failure.
Defaults to 3.
expirationOffsetSeconds <number> -
The number of seconds less than the token expiration to cache the token.
Defaults to 300.

Upstream Firebase User Auth Policy

Configuration

Policy Options

Using the Policy