Javascript Object Notation

Specification: http://json.org

Implementation

The source code of the format-type is available here: https://git.rwth-aachen.de/acs/public/villas/node/-/blob/master/lib/formats/json.cpp

Configuration

The Javascript Object Notation format-type supports all generic format options plus the following:

indent (integer) = 0

Pretty-print the result, using newlines between array and object items, and indenting with n spaces. The valid range for n is between 0 and 31 (inclusive), other values result in an undefined output. If the settings is not used or is 0, no newlines are inserted between array and object items.

compact (boolean) = false

This flag enables a compact representation, i.e. sets the separator between array and object items to "," and between object keys and values to ":". Without this flag, the corresponding separators are ", " and ": " for more readable output.

ensure_ascii (boolean) = false

If this flag is used, the output is guaranteed to consist only of ASCII characters. This is achieved by escaping all Unicode characters outside the ASCII range.

sort_keys (boolean) = false

If this flag is used, all the objects in output are sorted by key. This is useful e.g. if two JSON texts are diffed or visually compared.

escape_slash (boolean) = false

Escape the / characters in strings with \/.

Example Configuration

nodes = {
        node = {
                type = "file"
                uri = "/dev/null"

                format = {
                        type = "json"

                        indent = 4
                        compact = true
                        ensure_ascii = true
                        escape_slash = false
                        sort_keys = true
                }
        }
}

Example Payload

The structure of the JSON format is closely aligned with VILLASnode's internal data representation.

[
  {
    "ts": {
      "origin": [
        1556787289,
        492436800
      ]
    },
    "sequence": 55,
    "data": [
      0.022245,
      -1,
      true,
      {
          "real": 1.23,
          "imag": 4.56
      }
    ]
  }
]