Unless otherwise configured, the client libraries use Application Default Credentials to authenticate with Google Cloud Services. While this works for most applications, in some cases you may need to override this default. You can do so by providing the UnifiedCredentialsOption The following example shows how to explicitly load a service account key file:
[](std::string const& keyfile) {
auto is = std::ifstream(keyfile);
is.exceptions(std::ios::badbit); // Minimal error handling in examples
auto contents = std::string(std::istreambuf_iterator<char>(is.rdbuf()), {});
auto options =
google::cloud::Options{}.set<google::cloud::UnifiedCredentialsOption>(
google::cloud::MakeServiceAccountCredentials(contents));
return google::cloud::documentai_v1::DocumentProcessorServiceClient(
google::cloud::documentai_v1::MakeDocumentProcessorServiceConnection(
options));
}
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-03-14 UTC."],[[["This page details the different versions of the Document AI C++ client library, ranging from version 2.11.0 to the latest release candidate 2.37.0-rc."],["The latest version of the C++ client library is 2.37.0-rc, with previous stable versions also listed for reference, allowing users to access specific features and documentation for each release."],["The default authentication for the client libraries relies on Application Default Credentials, but users can override this by utilizing the UnifiedCredentialsOption."],["An example is given on how to override the default authentication by loading a service account key file and using it to construct a `DocumentProcessorServiceClient`."],["Users are advised to refer to the \"Best practices for managing service account keys\" guide and the \"Authentication Components\" for more information on managing credentials."]]],[]]
