Stream-Deserialize JSON from Azure Blob Storage in .NET

March 15, 2023 1 min read BEN ABT

System.Text.Json is currently the most modern way to handle Json files efficiently. Efficiency here also means that memory sparing files are read in.

A very efficient way to handle Json files is not to load them into a string first, but to implement the deserialization via streams. This keeps the application more scalable and performant.

System.Text.Json has this built in, so such an implementation can be done within a few lines.

C#
 1// Create Client
 2BlobContainerClient container = new(_options.ConnectionString, _options.ContainerName);
 3BlobClient blobClient = container.GetBlobClient(_options.BlobPath);
 4
 5// check if blob exists
 6Azure.Response<bool> exists = await blobClient.ExistsAsync(ct).ConfigureAwait(false);
 7if (exists.Value is false)
 8{
 9    return null;
10}
11
12// Get Blob Stream
13BlobOpenReadOptions readOptions = new(allowModifications: false);
14using Stream stream = await blobClient.OpenReadAsync(readOptions, ct).ConfigureAwait(false);
15
16// read json
17JsonSerializerOptions jsonOpions = new();
18
19MyDeserializationTargetClass? myDeserializedObject = await JsonSerializer
20    .DeserializeAsync<MyDeserializationTargetClass>(stream, jsonOpions, ct)
21    .ConfigureAwait(false);