Apache Camel to Firebase Cloud Messaging API 400 Bad Request Error NOT_A_JSON_REQUEST

Question

Calling the Firebase API is successful from Postman but Apache Camel-Spring Boot app returns an error.

API: https://fcm.googleapis.com/fcm/notification?notification_key_name=expectedvalue

Http Method: GET

Headers:
Authorization: expectedvalue
Content-Type: application/json
project_id: expectedvalue

Response Code: 400
Response Text: Bad Request
Response: {"error":"NOT_A_JSON_REQUEST"}

Calling from the Java app with below syntax:
.toD(https://fcm.googleapis.com/fcm/notification?notification_key_name=expectedvalue)

All required headers are set. Body is empty. HttpMethod also set as GET.

Update: --Added code--

public class MyRouteBuilder extends RouteBuilder{  

@Override  
    public void configure() throws Exception {  
        from("direct:notifyroute")  
        .bean(FirebaseNM.class, "getNotificationKey")  
        .setHeader("CamelHttpMethod", constant("GET"))  
        .toD("https://fcm.googleapis.com/fcm/notification?notification_key_name=expectedvalue").log("${body}");  
        //.to("https://fcm.googleapis.com/fcm/notification?notification_key_name=expectedvalue").log("${body}"); //Same error is thrown when I use 'to'  
    }  
}  

public class FirebaseNM{  
public void getNotificationKey(Exchange exchange){  
        exchange.getIn().removeHeaders("*"); //Code throws same error with or without this  
        exchange.removeProperties("*"); //Code throws same error with or without this  
        exchange.getIn().setBody(""); //Code throws same error with or without this  
        exchange.getIn().setHeader("Authorization", SERVER_KEY_VALUE);  
        exchange.getIn().setHeader("Content-Type", "application/json");  
        exchange.getIn().setHeader("project_id", PROJECT_ID_VALUE);          
    }  
}  

Alternate code that doesn't work:  
    rest().get("/nKey").route().removeHeaders("*")  
        .setHeader("Authorization", constant("server-key-value"))  
        .setHeader("Content-Type", constant("application/json"))  
        .setHeader("project_id", constant("project-id-value"))  
        .to("https://fcm.googleapis.com/fcm/notification?notification_key_name=key-name-value")  
        .endRest();

Update: --Question--
Is there a way to view error/exception details on Firebase console or to get detailed response from the API?

Update: --Question 2-- Firebase cloud messaging documentation does not mention the error(in the Enums columns) I'm receiving.
https://firebase.google.com/docs/reference/fcm/rest/v1/ErrorCode
Any other documentation I should look at?

without seeing your spring code, we wouldn't know where the error could be — beastlyCoder

Prashant Prashant · Accepted Answer · 2020-08-10T05:32:56

Have you considered https://firebase.google.com/docs/functions/writing-and-viewing-logs? If you have access to the server this might be an option.

Apache Camel to Firebase Cloud Messaging API 400 Bad Request Error NOT_A_JSON_REQUEST

1 Answers