Revalidate an already validated document

When parsing a YAML document you may wish to do more than one validation pass over a document.

This is needed when:

  • It simplifies your code to apply validation in stages.
  • You want to validate recursively.
  • One part of the document validation depends upon another (this is the example given below).

Example yaml_snippet:

capitals:
  UK: 1
  Germany: 2
countries:
  - Germany
  - UK
from strictyaml import Str, Int, Map, Seq, Any, load
from ensure import Ensure

overall_schema = Map({"capitals": Any(), "countries": Seq(Str())})
parsed = load(yaml_snippet, overall_schema)

Reparse mapping:

Ensure(parsed.data['capitals']['UK']).equals("1")
parsed['capitals'].revalidate(Map({capital: Int() for capital in parsed.data['countries']}))
Ensure(parsed.data['capitals']['UK']).equals(1)

Reparse scalar:

Ensure(parsed.data['capitals']['UK']).equals("1")
parsed['capitals']['UK'].revalidate(Int())

Ensure(parsed.data['capitals']['UK']).equals(1)
Ensure(parsed['capitals']['UK'].data).is_an(int)

Parse error:

capitals:
  UK: 1
  Germany: 2
  France: 3
countries:
  - Germany
  - UK
parsed['capitals'].revalidate(Map({capital: Int() for capital in parsed.data['countries']}))
strictyaml.exceptions.YAMLValidationError:
while parsing a mapping
unexpected key not in schema 'France'
  in "<unicode string>", line 4, column 1:
      France: '3'
    ^ (line: 4)

Executable specification

Page automatically generated from revalidation.story.