# Interface CredentialsHelper

All Known Implementing Classes:
  `GoogleCredentialsHelper`

public interface CredentialsHelper
This interface provides a method to convert a service account JSON string to a Google Credentials object.

Additionally, contains helper methods that aid with transfering the credentials' data to the HttpRequest.Builder object

- ## Method Summary

  Modifier and Type
  Method
  Description
  `com.google.auth.Credentials`
  `getGoogleCredentials(@Nullable String serviceAccountJson)`
  Converts a service account JSON string to a Google Credentials object.
  `static HttpRequest.Builder`
  `populateHeaders(HttpRequest.Builder builder, com.google.auth.Credentials credentials)`
  Populates the headers (such as Authorization or x-goog-project) in the HttpRequest.Builder with the metadata from the credentials.

- ## Method Details

  - ### getGoogleCredentials

    com.google.auth.Credentials getGoogleCredentials(@Nullable String serviceAccountJson) throws IOException
    Converts a service account JSON string to a Google Credentials object.
    Parameters:
      `serviceAccountJson` - The service account JSON string.
    Returns:
      A Google Credentials object.
    Throws:
      `IOException` - when an error occurs during the conversion.

  - ### populateHeaders

    static HttpRequest.Builder populateHeaders(HttpRequest.Builder builder, com.google.auth.Credentials credentials) throws IOException
    Populates the headers (such as Authorization or x-goog-project) in the HttpRequest.Builder with the metadata from the credentials.
    Parameters:
      `builder` - HttpRequest.Builder object to populate the headers
      `credentials` - Credentials object containing the metadata
    Returns:
      HttpRequest.Builder object with the headers populated
    Throws:
      `IOException` - if an error occurs when getting the metadata from the credentials