Create Document in Google Cloud Firestore Using v1 Client Library Wrapper

Question

I am trying to create and add a document to GCP Firestore using the .Net library for GCP: Google.Cloud.Firestore.V1 , however, I cannot figure out how to use the CreateDocumentRequest object to call the CreateDocumentAsync method. Here's a snippet of a method that takes in a document which is then passed to the CreateDocumentRequest. I attempt to cast the document object to type Document but I get an Invalid cast exception:

public async Task<Document> CreateDocumentAsync(object document,
        CancellationToken cancellationToken = default)
    {

        var docRequest = new CreateDocumentRequest
        {
            Document = (Document)document,
            CollectionId = _collectionName,
            Parent = _collectionReference.Parent.Path
        };

        return await _fireStoreDb.Client.CreateDocumentAsync(
            docRequest, cancellationToken);
    }

How can I convert a custom object into type Google.Cloud.Firestore.V1 so that I may set the document data when creating the document?

The documentation for Google.Cloud.Firestore.V1 shows snippets that use it in the following way:

 public async Task CreateDocumentRequestObjectAsync()
    {
        // Snippet: CreateDocumentAsync(CreateDocumentRequest, CallSettings)
        // Additional: CreateDocumentAsync(CreateDocumentRequest, CancellationToken)
        // Create client
        FirestoreClient firestoreClient = await FirestoreClient.CreateAsync();
        // Initialize request argument(s)
        CreateDocumentRequest request = new CreateDocumentRequest
        {
            Parent = "",
            CollectionId = "",
            DocumentId = "",
            Document = new Document(),
            Mask = new DocumentMask(),
        };
        // Make the request
        Document response = await firestoreClient.CreateDocumentAsync(request);
        // End snippet
    }

My intent is to replace the "Document" property within the CreateDocumentRequest with my own document and add that to firestore.

I can see how it is done using the Google.Cloud.Firestore library as shown below:

public async Task AddAsync()
    {
        string projectId = _fixture.ProjectId;
        // Sample: AddAsync
        FirestoreDb db = FirestoreDb.Create(projectId);

        // Create a document with a random ID in the "cities" collection.
        CollectionReference collection = db.Collection("cities");
        City city = new City
        {
            Name = "Los Angeles",
            Country = "USA",
            State = "CA",
            IsCapital = false,
            Population = 3900000L
        };

        // Alternatively, collection.Document("los-angeles").Create(city);
        DocumentReference document = await collection.AddAsync(city);
        // End sample
    }

However, I would like to do the same using Google.Cloud.Firestore.V1 client library wrapper provided.

Answer 1

Unfortunately, the implementation you are trying to make with the Google.Cloud.Firestore.V1 library, passing a different object from the Document object class and trying to use it in the CreateDocumentRequest is not possible, or at least is not as simple as your last snippet example with Google.Cloud.Firestore library.

To achieve this, you would need to create a custom object with the MapField and other similar properties that could pass through as a Document Object with the same format the documentation describes.

If it’s possible to use the normal procedure that is described in the quoted documentation snippet that would be the best option, lastly open a feature request. Here is the template for this case with Cloud functions.