Transfer data between the Arrow memory format and JSON line-delimited records.
See the module level documentation for the
[`reader`] and [`writer`] for usage examples.
# Binary Data
As per [RFC7159] JSON cannot encode arbitrary binary data. A common approach to workaround
this is to use a [binary-to-text encoding] scheme, such as base64, to encode the
input data and then decode it on output.
```
# use std::io::Cursor;
# use std::sync::Arc;
# use arrow_array::{BinaryArray, RecordBatch, StringArray};
# use arrow_array::cast::AsArray;
# use arrow_cast::base64::{b64_decode, b64_encode, BASE64_STANDARD};
# use arrow_json::{LineDelimitedWriter, ReaderBuilder};
#
// The data we want to write
let input = BinaryArray::from(vec![b"\xDE\x00\xFF".as_ref()]);
// Base64 encode it to a string
let encoded: StringArray = b64_encode(&BASE64_STANDARD, &input);
// Write the StringArray to JSON
let batch = RecordBatch::try_from_iter([("col", Arc::new(encoded) as _)]).unwrap();
let mut buf = Vec::with_capacity(1024);
let mut writer = LineDelimitedWriter::new(&mut buf);
writer.write(&batch).unwrap();
writer.finish().unwrap();
// Read the JSON data
let cursor = Cursor::new(buf);
let mut reader = ReaderBuilder::new(batch.schema()).build(cursor).unwrap();
let batch = reader.next().unwrap().unwrap();
// Reverse the base64 encoding
let col: BinaryArray = batch.column(0).as_string::().clone().into();
let output = b64_decode(&BASE64_STANDARD, &col).unwrap();
assert_eq!(input, output);
```
[RFC7159]: https://datatracker.ietf.org/doc/html/rfc7159#section-8.1
[binary-to-text encoding]: https://en.wikipedia.org/wiki/Binary-to-text_encoding