Module json_schema

Provides interfaces to generate a regular expression based on a given JSON schema.

An optional custom pattern could be passed as well to handle whitespace within the regex. If None, the default WHITESPACE pattern is used.

Returns errors if JSON schema’s content is invalid or some feature is not yet supported for regex generation.

Supported features

Note, that only some of the features of JSON schema are supported for regex generation.

Supported constraints

Common

• type
  • Specifies the data type (string, number, integer, boolean, array, object, null).
• enum
  • Lists the allowed values.
• const
  • Specifies a single allowed value.

Object

• properties
  • Defines the expected properties of an object and their schemas.
• required
  • Lists the properties that must be present.
• additionalProperties
  • Specifies whether additional properties are allowed or defines their schema.
• minProperties
  • Minimum number of properties required.
• maxProperties
  • Maximum number of properties allowed.

Array

• items
  • Defines the schema for array elements (single schema or a schema per index).
• prefixItems
  • Specifies schemas for the first few elements of an array (tuple validation).
• minItems
  • Minimum number of items required in the array.
• maxItems
  • Maximum number of items allowed in the array.

String

• minLength
  • Minimum string length.
• maxLength
  • Maximum string length.
• pattern
  • Regular expression the string must match.
• format
  • Specifies a pre-defined format, these are supported FormatType

Number

• minDigitsInteger
  • Specifies minimum number of digits in the integer part of a numeric value.
• maxDigitsInteger
  • Specifies maximum number of digits in the integer part of a numeric value.
• minDigitsFraction
  • Constraints on minimum number of digits allowed in the fractional part of a numeric value.
• maxDigitsFraction
  • Constraints on maximum number of digits allowed in the fractional part of a numeric value.
• minDigitsExponent
  • Defines minimum number of digits in the exponent part of a scientific notation number.
• maxDigitsExponent
  • Defines maximum number of digits in the exponent part of a scientific notation number.

Integer

• minDigits
  • Defines the minimum number of digits.
• maxDigits
  • Defines the maximum number of digits.

Logical

• allOf
  • Combines multiple schemas; all must be valid.
• anyOf
  • Combines multiple schemas; at least one must be valid.
• oneOf
  • Combines multiple schemas; exactly one must be valid.

Recursion

Currently maximum recursion depth is cautiously defined at the level 3.

Note, that in general recursion in regular expressions is not the best approach due to inherent limitations and inefficiencies, especially when applied to complex patterns or large input.

But often, even simple referential JSON schemas will produce enormous regex size, since it increases exponentially in recursive case, which likely to introduce performance issues by consuming large amounts of time, resources and memory.

References

Only local references are currently being supported.

Unconstrained objects

An empty object means unconstrained, allowing any JSON type.

Re-exports

pub use types::*;

Modules

types

Static collection of regular expressions for JSON and format types used in generating a regular expression string based on a given JSON schema.

Functions

regex_from_str

Generates a regular expression string from given JSON schema string.

regex_from_value

Generates a regular expression string from serde_json::Value type of JSON schema.