Google Cloud Natural Language

Google Cloud Natural Language extracts insights from text, including sentiment, entities and content categories. The gRPC API is exposed through the google.cloud.language.v1.LanguageService service, reached at language.googleapis.com:443 over TLS, with the main methods AnalyzeSentiment, AnalyzeEntities and ClassifyText.

Requests are built with typed classes such as TsgcGRPCLanguageAnalyzeSentimentRequest and TsgcGRPCLanguageAnalyzeEntitiesRequest, each carrying a Document whose DocType is set to PLAIN_TEXT together with the text content to analyze.

The example below authenticates with a service-account JWT, wires a TsgcGRPCClient over a TsgcHTTP2Client to the Natural Language host, sets the authorization Bearer metadata and calls AnalyzeSentiment on a plain-text sentence:

    oHTTP2 := TsgcHTTP2Client.Create(nil);
    oHTTP2.Host := 'language.googleapis.com';
    oHTTP2.Port := 443;
    oHTTP2.TLS := True;

    oGRPC := TsgcGRPCClient.Create(nil);
    oGRPC.Client := oHTTP2;

    // service-account JWT authentication
    oGRPC.GoogleCloudOptions.JWT.KeyFile := 'service-account.json';
    oGRPC.GoogleCloudOptions.JWT.API_Endpoint := 'https://language.googleapis.com/';
    oGRPC.DefaultMetadata.AddValue('authorization', 'Bearer ' + oGRPC.GoogleCloudOptions.JWT.Token);

    // build the typed request and call the method
    oRequest := TsgcGRPCLanguageAnalyzeSentimentRequest.Create;
    try
      oRequest.Document.DocType := 'PLAIN_TEXT';
      oRequest.Document.Content := 'I really love this product, it works great!';
      oResponse := oGRPC.Call('google.cloud.language.v1.LanguageService', 'AnalyzeSentiment', oRequest.ToBytes);
      ShowMessage(oResponse.DataString);
    finally
      oRequest.Free;
    end;