How to deserialize cosmos document for desired POCO class?

Question

I have a web job with CosmosDBTrigger. I want to deserialize this Document per my POCO class, but I am getting 'S' is an invalid start of a value. Path: $ | LineNumber: 0 | BytePositionInLine: 0. error.

Approaches:

I tried var mappedObject = JsonSerializer.Deserialize<T>(document.ToString()); but received error.
Same with var mappedObject = JsonConvert.DeserializeObject<Inspection>(document.ToString());. This is with Newtonsoft.
This question talks about document.Resource.ToString() but I don't even see .Resource option. Is this related to the packages I am using? (see below)

Nuget Packages:

<PackageReference Include="Microsoft.Azure.DocumentDB.Core" Version="2.18.0" />
<PackageReference Include="Microsoft.Azure.WebJobs.Extensions.CosmosDB" Version="4.2.0" />

General Questions:

Why deleting record is not triggering CosmosDBTrigger?
Why am I not seeing .Resource property in Document?
Can I see the DB action such as insert, update, delete on back end when CosmosDBTrigger is triggered?

Code:

Program.cs (snippet of adding cosmos in webjob)

var builder = new HostBuilder()
    .UseEnvironment(environment)
    .ConfigureWebJobs(b =>
    {
        b.AddCosmosDB(_ =>
        {
            _.ConnectionMode = ConnectionMode.Direct;
        });
    })

Listener.cs

public class Listener
{
    private readonly ILogger<Listener> _logger;

    public Listener(ILogger<Listener> logger)
    {
        _logger = logger;
    }

    public async Task ProcessDocumentAsync(
        [CosmosDBTrigger(
            databaseName: Configurations.DatabaseName,
            containerName: Configurations.ContainerName,
            Connection = Configurations.ConnectionString,
            CreateLeaseContainerIfNotExists = true
        )]
        IReadOnlyList<Document> documents) 
// If I change this to IReadOnlyList<MyContainerObject> documents then it works but I would also like to know if this is update,insert or delete by using `Document` properties. (Not sure if this is possible or not)
    {
        var totalDocuments = documents.Count;
       
        _logger.Info(
            $"[{nameof(Listener)}]: Received {Configurations.DatabaseName}/{Configurations.ContainerName}, deliveryCount:{totalDocuments}");

        foreach (var document in documents)
        {
            await ProcessDocument(document);
        }
    }

    public async Task ProcessDocument(Document document)
    {
        try
        {
            // Getting error here
            var mappedObject = JsonSerializer.Deserialize<MyContainerObject>(document.ToString());
            _logger.Info($"ProcessDocument: {{@document}}", args: new object[] { document });
        }
        catch (Exception exception)
        {
            _logger.Error(
                $"Exception while processing : {{@exception}} document: {{@document}}",
                args: new object[] { exception.GetBaseException(), document });
            throw;
        }
    }
}

How to deserialize cosmos document for desired POCO class?

0 Answers0