Can this be used to deserialize an avro file to json?

[famattsson]

I have an avro file in binary that I want to convert into a json string. Does this project support that?

[dstelljes]

It does, you should be able to do something like:

var schema = new JsonSchemaReader.Read("...");
var deserialize = new BinaryDeserializerBuilder().BuildDelegate<dynamic>(schema);
var serialize = new JsonSerializerBuilder().BuildDelegate<dynamic>(schema);

using var stream = new MemoryStream();
using var writer = new Utf8JsonWriter(stream)
{
    serialize(deserialize(new BinaryReader(File.ReadAllBytes("..."))), writer);
}

var json = stream.ToString();

If you want "regular JSON" instead of Avro JSON, you could also just use the System.Text.Json serializer instead of the Chr.Avro one.

[famattsson]

Hm i've tried it now.

fileDownload.Value.Content.CopyTo(ms);
var fileBytes = ms.ToArray();
var avroSchema = new JsonSchemaReader().Read(File.ReadAllText("AvroSchema.json"));
var deserialize = new BinaryDeserializerBuilder().BuildDelegate<dynamic>(avroSchema);
var reader = new BinaryReader(fileBytes);
var deserialized = deserialize(ref reader);
var json = JsonSerializer.Serialize(deserialized);

Here is the schema

{
    "name": "Microsoft.Streaming.Avro.GenericFromIRecord0",
    "type": "record",
    "fields": [
        {
            "name": "deviceId",
            "type": [
                "null",
                "string"
            ]
        },
        {
            "name": "error",
            "type": [
                "null",
                "string"
            ]
        },
        {
            "name": "entityId",
            "type": [
                "null",
                "string"
            ]
        },
        {
            "name": "ts",
            "type": [
                "null",
                "string"
            ]
        },
        {
            "name": "value",
            "type": [
                "null",
                "string"
            ]
        },
        {
            "name": "parameterId",
            "type": [
                "null",
                "string"
            ]
        },
        {
            "name": "valueType",
            "type": [
                "null",
                "string"
            ]
        },
        {
            "name": "EventProcessedUtcTime",
            "type": [
                "null",
                "string"
            ]
        }
    ]
}

I'm getting this error though: Exception: Chr.Avro.InvalidEncodingException: Invalid union index; expected a value in [0-2). This may indicate invalid encoding earlier in the stream.

[famattsson]

Here is the avro written to a file.
avrofile.txt

[dstelljes]

Ah okay, it looks like that's an object container file. Unfortunately Chr.Avro currently doesn't implement a reader for that format: #156

[famattsson]

Oh, okay. That's a shame. Thanks for your help. Do you know of any other package that supports this format?

[dstelljes]

Apache.Avro implements it here: https://github.com/apache/avro/blob/main/lang/csharp/src/apache/main/File/DataFileReader.cs