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From Miki Tebeka <miki.teb...@gmail.com>
Subject Re: Generic Avro Classification and Deserialization
Date Fri, 18 Jan 2013 18:49:08 GMT
Avro files have a "magic" prefix of "Obj\0x1", this might help.
The schema is always embedded in the avro file in the "meta" field.

On Thu, Jan 17, 2013 at 2:11 PM, Public Network Services <
publicnetworkservices@gmail.com> wrote:

> Folks,
> I am involved in a project to extract data from a large number of files
> (to be provided at some point), in numerous formats, among which is some
> Avro files (both binary and JSON-encoded), and thus I am looking for the
> best way to tackle this.
> One of the things we would (ideally) like to do is auto-classify the data
> generically, i.e. read a few lines or bytes off a file and be able to tell
> what kind of format it is.
> This is fairly easy to do with, say, (non-Avro) JSON files, but I am not
> sure how this would be done for Avro.
> For one thing, there is the necessity of a Schema, about which the
> documentation says that
>    - "Avro data is always serialized with its schema. Files that store
>    Avro data should always also include the schema for that data in the same
>    file."
> However, the Java code examples posted on the project website imply that
> the Schema is supplied as a separate file and I am not sure whether this is
> only the case with RPC.
> Are there any code examples for detecting the encoding format
> (binary/json) of the data file, assessing whether there is a schema
> embedded in it and extracting that schema?
> Thanks!

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