json_stream_writer_task.md

JsonStreamWriterTask

Writes each received array as a JSON document on its own line (JSON Lines format), in a file whose path is set in the options. As a blocking task, it waits until all inputs have been received and then outputs the file path.

Task reference

• Service: CleverAge\ProcessBundle\Task\File\JsonStream\JsonStreamWriterTask
• Code: json_stream_writer (task: json_stream_writer)
• Blocking task

Accepted inputs

array: data to encode. An UnexpectedValueException is thrown for any other type. Underlying method is json_encode.

Possible outputs

string: path of the written file (with placeholders replaced), once all inputs have been processed.

Options

Code	Type	Required	Default	Description
file_path	string	X		Path of the file to write to; missing parent directories are created. Placeholders {date}, {date_time}, {timestamp} and {unique_token} are replaced in the path
mode	string		wb	File open mode (see fopen mode parameter): wb overwrites the file, ab appends to it
spl_file_object_flags	array|null		null	List of SplFileObject flags, summed and passed to SplFileObject::setFlags. null means DROP_NEW_LINE, READ_AHEAD and SKIP_EMPTY; an empty array means no flag
json_flags	array|null		null	List of JSON flags, summed and passed to json_encode. null means JSON_THROW_ON_ERROR; an empty array means no flag

Examples

# Task configuration level
entry:
  task: constant_iterable_output
  options:
    output:
      - column1: value1-1
        column2: value2-1
      - column1: value1-2
        column2: value2-2
  outputs: [write]
write:
  task: json_stream_writer
  options:
    file_path: '%kernel.project_dir%/var/data/json_stream_writer_{date_time}.json'
    json_flags:
      - !php/const JSON_THROW_ON_ERROR
      - !php/const JSON_UNESCAPED_SLASHES
      - !php/const JSON_UNESCAPED_UNICODE

Notes

• {date} is replaced by Ymd, {date_time} by Ymd_His, {timestamp} by the Unix timestamp and {unique_token} by a uniqid('', true) value (23 characters, containing a dot).
• The parent directory of the file is created (recursively) if it does not exist.
• Using JSON_PRETTY_PRINT produces multi-line documents: the file can no longer be read by JsonStreamReaderTask.
• The file is released at the end of the process.