ruby/csv

====== Option +field_size_limit+

Specifies the \Integer field size limit.

Default value:
  CSV::DEFAULT_OPTIONS.fetch(:field_size_limit) # => nil

This is a maximum size CSV will read ahead looking for the closing quote for a field.
(In truth, it reads to the first line ending beyond this size.)
If a quote cannot be found within the limit CSV will raise a MalformedCSVError,
assuming the data is faulty.
You can use this limit to prevent what are effectively DoS attacks on the parser.
However, this limit can cause a legitimate parse to fail;
therefore the default value is +nil+ (no limit).

For the examples in this section:
  str = <<~EOT
    "a","b"
    "
    2345
    ",""
  EOT
  str # => "\"a\",\"b\"\n\"\n2345\n\",\"\"\n"

Using the default +nil+:
  ary = CSV.parse(str)
  ary # => [["a", "b"], ["\n2345\n", ""]]

Using <tt>50</tt>:
  field_size_limit = 50
  ary = CSV.parse(str, field_size_limit: field_size_limit)
  ary # => [["a", "b"], ["\n2345\n", ""]]

---

Raises an exception if a field is too long:
  big_str = "123456789\n" * 1024
  # Raises CSV::MalformedCSVError (Field size exceeded in line 1.)
  CSV.parse('valid,fields,"' + big_str + '"', field_size_limit: 2048)