Gokul Kulkarni Gokul Kulkarni - 2 months ago 8
Android Question

Android: Firebase auth for Cloud End Point not working

I have followed the link and have done the configuration on the server as mentioned.

"/users":
post:
description: "<Description>"
operationId: "<OperationID>"
produces:
- "application/json"
responses:
200:
description: "user List"
schema:
$ref: "#/definitions/echoMessage"
parameters:
- description: "Search Criteria"
in: body
name: message
required: true
schema:
$ref: "#/definitions/echoMessage"
security:
- firebase: []


and

firebase:
authorizationUrl: ""
flow: "implicit"
type: "oauth2"
x-google-issuer: "https://securetoken.google.com/<Project-ID>"
x-google-jwks_uri: "https://www.googleapis.com/service_accounts/v1/metadata/x509/securetoken@system.gserviceaccount.com"


And after going through JWT standards I came to know that while calling calling the service we have to add Authorization header with Bearer so I have added the header as follows,

Authorization: Bearer

I initially tried with

String token = FirebaseInstanceId.getInstance().getToken();


But it gave error so I tried with,

FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
if (firebaseUser != null) {

firebaseUser.getIdToken(true)
.addOnSuccessListener(new OnSuccessListener<GetTokenResult>() {
@Override
public void onSuccess(GetTokenResult getTokenResult) {
String token = getTokenResult.getToken();
SharedPreferences.Editor editor = mSharedPreferences.edit();
editor.putString(Constants.PREFS_FCM_TOKEN, token);
editor.apply();
}
});
}


But even with both codes I am getting error as 401 and invalid_token

Answer Source

After so many days of struggle I am able to solve the issue.

I solved the issue by following this,

    "/users":
post:
  description: "<Description>"
  operationId: "<OperationID>"
  produces:
  - "application/json"
  responses:
    200:
      description: "user List"
      schema:
        $ref: "#/definitions/echoMessage"
  parameters:
  - description: "Search Criteria"
    in: body
    name: message
    required: true
    schema:
      $ref: "#/definitions/echoMessage"
  security:
    - firebase: []

and

firebase:
authorizationUrl: ""
flow: "implicit"
type: "oauth2"
x-google-issuer: "https://securetoken.google.com/<Project-ID>"
x-google-jwks_uri: "https://www.googleapis.com/service_accounts/v1/metadata/x509/securetoken@system.gserviceaccount.com"
x-google-audiences: "<Project-ID>" //I have added this, this was the main culprit.

as mentioned in the comment, I was missing

x-google-audiences: ""

in the server configuration.

And for another clarification for which token to use: We have to use the second approach that I have mentioned in the question, i.e, as below,

FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
    if (firebaseUser != null) { 

        firebaseUser.getIdToken(true)
                .addOnSuccessListener(new OnSuccessListener<GetTokenResult>() { 
                    @Override 
                    public void onSuccess(GetTokenResult getTokenResult) {
                        String token = getTokenResult.getToken();
                        SharedPreferences.Editor editor = mSharedPreferences.edit();
                        editor.putString(Constants.PREFS_FCM_TOKEN, token);
                        editor.apply();
                    } 
                }); 
    }