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Upstream Firebase User Auth Policy

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

{
"name": "my-upstream-firebase-user-auth-inbound-policy",
"policyType": "upstream-firebase-user-auth-inbound",
"handler": {
"export": "UpstreamFirebaseUserAuthInboundPolicy",
"module": "$import(@zuplo/runtime)",
"options": {
"serviceAccountJson": "$env(SERVICE_ACCOUNT_JSON)",
"webApiKey": "$env(WEB_API_KEY)",
"userId": "1234",
"developerClaims": {
"premium": true
}
}
}
}
  • name the name of your policy instance. This is used as a reference in your routes.
  • policyType the identifier of the policy. This is used by the Zuplo UI. Value should be upstream-firebase-user-auth-inbound.
  • handler/export The name of the exported type. Value should be UpstreamFirebaseUserAuthInboundPolicy.
  • handler/module the module containing the policy. Value should be $import(@zuplo/runtime).
  • handler/options The options for this policy:
    • serviceAccountJson

      The Google Service Account key in JSON format. Note you can load this from environment variables using the $env(ENV_VAR) syntax.

    • userId

      The userId to use as the custom token's subject.

    • userIdPropertyPath

      The property on the incoming request.user object to retrieve the value of the userId

    • developerClaims

      Optional additional claims to include in the custom token's payload.

    • webApiKey

      The Firebase Web API Key (found in project settings)

    • tokenRetries

      The number of times to retry fetching the token in the event of a failure. Defaults to 3.

    • expirationOffsetSeconds

      The number of seconds less than the token expiration to cache the token. Defaults to 300 seconds.

Read more about how policies work