Cosmos DB Recipe — C# (.NET) — REFERENCE ONLY

Cosmos DB SDK Setup

NuGet Packages

<PackageReference Include="Microsoft.Azure.Cosmos" Version="3.*" />
<PackageReference Include="Azure.Identity" Version="1.13.*" />

Program.cs (additions)

Add these lines — do NOT replace the existing file:

using Azure.Identity;
using Microsoft.Azure.Cosmos;

builder.Services.AddSingleton(_ =>
{
    var endpoint = builder.Configuration["COSMOS_ENDPOINT"];
    return new CosmosClient(endpoint, new DefaultAzureCredential());
});

CRUD Endpoints

Add to Program.cs after app is built:

app.MapGet("/api/items", async (CosmosClient cosmos) =>
{
    var container = cosmos
        .GetDatabase(Environment.GetEnvironmentVariable("COSMOS_DATABASE_NAME"))
        .GetContainer(Environment.GetEnvironmentVariable("COSMOS_CONTAINER_NAME"));
    var query = container.GetItemQueryIterator<dynamic>("SELECT * FROM c");
    var results = new List<dynamic>();
    while (query.HasMoreResults)
        results.AddRange(await query.ReadNextAsync());
    return Results.Ok(results);
});

Files to Modify