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class method

Psych.safe_dump

Psych.safe_dump(o) → string of yaml

Psych.safe_dump(o, options) → string of yaml

Psych.safe_dump(o, io) → io object passed in

Psych.safe_dump(o, io, options) → io object passed in

# File tmp/rubies/ruby-3.2.0/ext/psych/lib/psych.rb, line 578
def self.safe_dump o, io = nil, options = {}
  if Hash === io
    options = io
    io      = nil
  end

  visitor = Psych::Visitors::RestrictedYAMLTree.create options
  visitor << o
  visitor.tree.yaml io, options
end

Safely dump Ruby object o to a YAML string. Optional options may be passed in to control the output format. If an IO object is passed in, the YAML will be dumped to that IO object. By default, only the following classes are allowed to be serialized:

Arbitrary classes can be allowed by adding those classes to the permitted_classes keyword argument. They are additive. For example, to allow Date serialization:

Example

Psych.safe_dump(yaml, permitted_classes: [Date])

Now the Date class can be dumped in addition to the classes listed above.

A Psych::DisallowedClass exception will be raised if the object contains a class that isn’t in the permitted_classes list.

Currently supported options are:

:indentation

Number of space characters used to indent. Acceptable value should be in 0..9 range, otherwise option is ignored.

Default: 2.

:line_width

Max character to wrap line at.

Default: 0 (meaning “wrap at 81”).

:canonical

Write “canonical” YAML form (very verbose, yet strictly formal).

Default: false.

:header

Write %YAML [version] at the beginning of document.

Default: false.

Example:

Example

# Dump an array, get back a YAML string
Psych.safe_dump(['a', 'b'])  # => "---\n- a\n- b\n"

# Dump an array to an IO object
Psych.safe_dump(['a', 'b'], StringIO.new)  # => #<StringIO:0x000001009d0890>

# Dump an array with indentation set
Psych.safe_dump(['a', ['b']], indentation: 3) # => "---\n- a\n-  - b\n"

# Dump an array to an IO with indentation set
Psych.safe_dump(['a', ['b']], StringIO.new, indentation: 3)

See also .parse_stream .safe_load .parser .safe_load_file also in 4.1 · 4.0 · 3.4 · 3.3 · 3.1

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