JsonWriter

class cometa.json.json_writer.JsonWriter(json_format=JsonFormat.COMPACT)

Bases: object

Provides a API for forward-only, non-cached writing of UTF-8 encoded JSON text.

This class allows for the incremental creation of JSON documents. It manages internal state to ensure syntactically valid JSON output.

Parameters:

json_format (JsonFormat)

__init__(json_format=JsonFormat.COMPACT)

Creates a new JSON writer instance.

Parameters:

json_format (JsonFormat) – The desired output format (COMPACT or PRETTY). Defaults to COMPACT.

Return type:

None

property refcount: int

Returns the number of active references to the underlying C object.

property encoded_size: int

Returns the current size of the encoded data in bytes.

property context: JsonContext

Returns the current context (ROOT, OBJECT, or ARRAY).

property last_error: str

Returns the last error message recorded for this writer.

reset()

Resets the writer, clearing all written data. The writer can be reused for new data without creating a new instance.

Return type:

None

encode()

Finalizes the JSON encoding and returns the resulting string.

Returns:

The generated JSON text.

Return type:

str

to_dict()

Parses the JSON into a Python dictionary for inspection.

Return type:

dict

write_start_object()

Begins a JSON object (‘{’) in the output.

Return type:

None

write_end_object()

Ends a JSON object (‘}’) in the output.

Return type:

None

write_start_array()

Begins a JSON array (‘[’) in the output.

Return type:

None

write_end_array()

Ends a JSON array (‘[’) in the output.

Return type:

None

write_property_name(name)

Writes a property name. Must be called within an Object context.

Parameters:

name (str) – The property key.

Return type:

None

write_null()

Writes a JSON null value.

Return type:

None

write_bool(value)

Writes a boolean value (true or false).

Parameters:

value (bool)

Return type:

None

write_str(value)

Writes a string value. The writer handles escaping automatically.

Parameters:

value (str) – The string content.

Return type:

None

write_int(value, as_string=False)

Writes an integer value.

Parameters:

• value (int | BigInt) – The integer to write.

• as_string (bool) – If True, writes the number as a string (e.g. “123”). Note: Very large integers (BigInts) are always written as strings by the underlying library to preserve precision.

Return type:

None

write_float(value, as_string=False)

Writes a floating point number.

Parameters:

• value (float) – The number to write.

• as_string (bool) – If True, writes the number as a quoted string.

Return type:

None

write_raw_value(value)

Writes a raw JSON fragment directly to the output.

Warning: The caller must ensure value is valid JSON.

Parameters:

value (str) – The raw JSON string (e.g., “[1, 2]”).

Return type:

None

write_json_object(obj)

Writes an existing JsonObject to the stream.

Parameters:

obj (JsonObject) – The parsed JSON object to write.

Return type:

None

write_bytes(data)

Writes binary data as a hexadecimal string.

Parameters:

data (bytes | Buffer) – The data to write.

Return type:

None

write_bech32(hrp, data)

Writes binary data encoded as a Bech32 string.

Parameters:

• hrp (str) – The human-readable part (prefix).

• data (bytes | Buffer) – The binary payload.

Return type:

None

__enter__()

Context manager entry. Returns self.

Return type:

JsonWriter

__exit__(exc_type, exc_val, exc_tb)

Context manager exit. Cleans up resources.

Return type:

None

__repr__()

Returns a string representation of the JsonWriter.

Return type:

str