SystemTextJsonForCosmosDb 0.1.1

SystemTextJsonForCosmosDb

A tiny package for using System.Text.Json with Cosmos DB.

Installing

Add the package to your project:

Using Package Manager

Install-Package SystemTextJsonForCosmosDb

PackageReference in your project file

<PackageReference Include="SystemTextJsonForCosmosDb" Version="0.1.0" />

Quick start (ASP.NET Core using Microsoft.Extensions.DependencyInjection)

Add the following code to your services registration code (e.g., in Startup's ConfigureServices, or anywhere you're adding to your IServiceCollection):

// replace with your options
JsonSerializerOptions mySerializerOptions = new()
{
    MaxDepth = 64,
    PropertyNamingPolicy = NamingPolicy.CamelCase,
};

services
    .AddSystemTextJsonForCosmosDb()
    .AddSingleton<IJsonSerializerOptionsProvider>(new JsonSerializerOptionsProvider(mySerializerOptions));

When you want to initialize a connection to Cosmos DB, you can inject the ICosmosClientOptionsProvider like this:

internal class MyRepository
{
    private CosmosClient client;

    public MyRepository(ICosmosClientOptionsProvider clientOptionsProvider)
    {
        config = options.Value;
        CosmosClientOptions clientOptions = clientOptionsProvider.GetCosmosClientOptions();
        client = new(
            // you should definitely be getting this from configuration, not hardcoding it...
            "https://myaccount.documents.azure.com",
            // You're using RBAC, not secret credentials, right?
            new DefaultAzureCredential(),
            clientOptions);
    }

    // ... methods that use the client in fun and interesting ways
}

Customizing

ICosmosSerializer

If you prefer to have full control over the serialization, perhaps because you already have a serializer implemented, you can implement the ICosmosSerializer interface and provide that instead:

services
    .AddSystemTextJsonForCosmosDb()
    .AddSingleton<ICosmosSerializer, MySerializer>();

NOTE: If both ICosmosSerializer AND IJsonSerializerOptionsProvider are registered, ICosmosSerializer will be used.

The following converters are highly recommended to be used if you implement your own serializer:

CosmosDateTimeOffsetJsonConverter
CosmosDateTimeJsonConverter
JsonStringEnumConverter
CosmosNullableDateTimeOffsetJsonConverter
CosmosNullableDateTimeJsonConverter
PatchOperationJsonConverter

IJsonSerializerOptionsProvider

This interface exposes just one method: GetJsonSerializerOptions(), which returns System.Text.Json.JsonSerializerOptions.

When using IJsonSerializerOptionsProvider, the library guarantees to:

• Not mutate your options. A new copy is created and used internally.
• Honor naming policies, except for two cases: the id and etag/_etag properties (case-insensitive) of any object being (de)serialized will be converted to "id" and "_etag", respectively.
• Preempt certain data type conversions:
  • DateTime, DateTimeOffset, and nullable variants will always use the format yyyy-MM-ddTHH:mm:ss.fffffffZ to conform to Cosmos DB standards.
  • Microsoft.Azure.Cosmos.PatchOperation will be converted using Cosmos DB naming, according to the RFC standard.