[
https://issues.apache.org/jira/browse/AVRO-3274?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17559013#comment-17559013
]
Kalle Niemitalo commented on AVRO-3274:
---------------------------------------
I have been trying to implement an Avro JSON encoder in a proprietary
application, as a C# class that implements the Avro.IO.Encoder interface. A
difficulty in this is that Encoder.WriteNull is called by
Resolver.EncodeDefaultValue but not by GenericWriter.WriteNull, so the JSON
{{null}} for Schema.Type.Null has to be written in some other way. This differs
from the Java org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion
method.
Also, Avro.IO.Encoder does not have WriteRecordStart and WriteRecordEnd
methods. This means methods like WriteInt have to detect where records start or
end, and write the JSON {{{}} and {{}}} delimiters when needed. If
empty record schemas (that do not have any fields) are to be supported, then
that becomes more difficult, as a single WriteInt(42) call may have to write
something like {{"field": 42, "almost_empty":
{"inner_empty":{}}, "empty": {}}}}}. It
is implementable, but I think it would be easier to implement something that
avoids the Avro.IO.Encoder interface and instead reads from an Avro.IO.Decoder
and writes JSON from that.
> Request for C# API to implement a JSON Encoder
> ----------------------------------------------
>
> Key: AVRO-3274
> URL: https://issues.apache.org/jira/browse/AVRO-3274
> Project: Apache Avro
> Issue Type: Improvement
> Components: csharp
> Affects Versions: 1.10.2
> Reporter: Andrew Benedek
> Priority: Major
>
> This is a request or improvement.
> I have a .NET Core application that needs to publish AVRO JSON encoded
> messages to our Confluent Kafka REST API. I can see that the Java and C++
> API's have a JSON encoder, but I couldn't tell from the documentation whether
> the C# API has it, or at least it doesn't seem to. The documentation for the
> C# API is a little light on for details. The Kafka REST API supports JSON,
> and AVRO JSON, but not binary AVRO from what I understand.
> The main problem facing the plain JSON we are currently publishing is that
> when using an AVRO schema and the union type, we hit the problem described
> here https://issues.apache.org/jira/browse/AVRO-2899. We need to generate
> the type information in the JSON in order to satisfy the validation in the
> Kafka REST API. Hence, the need for an AVRO JSON encoder.
> I can't re-write the .NET application, so I'm faced with the prospect of
> using either the Java or C++ API's with some sort of wrappers or
> interoperability framework, which I'm desperately trying to avoid.
> Any assistance or suggestions would be much appreciated.
--
This message was sent by Atlassian Jira
(v8.20.7#820007)
