s-exp.legba.json-schema — com.s-exp/legba 1.0.0-alpha117

JSON Schema validation utilities. Provides helpers to load, cache, and validate JSON Schemas

schema clj

(schema schema-uri
        &
        {:as _opts
         :keys [schema-validator-config]
         :or {schema-validator-config schema-validator-config}})

Loads and builds a JSON Schema validator instance from a URI or file path.

Arguments:

• schema-uri (string): Location of the JSON Schema (file:/..., http:/..., classpath:/..., etc)

• :schema-validator-config (optional): Custom SchemaValidatorsConfig (default: this namespace's schema-validator-config).

Returns:

An instance of the JSON Schema validator (com.networknt.schema.JsonSchema). This object can be reused to validate multiple values or payloads.

Example: (schema "classpath:///tmp/foo.schema.json") (schema "file:///data/schema/bar.json") (schema "https://schemas.org/example.schema.json")

schema-validator-config clj

Default reusable SchemaValidatorsConfig instance.

This configures the validator to:

• Enable JSON Schema reference preloading and caching
• Enable format assertions (per the JSON Schema spec)
• Set maximum reference nesting depth to 40
• Handle nullable fields correctly
• Use JSON_PATH for error paths in validation results

This config can be reused for schema load/validation for performance and consistency.

validate clj

(validate schema
          val
          &
          {:as _opts
           :keys [validation-result]
           :or {validation-result validation-result}})

Validates a value against a previously loaded or constructed schema.

Arguments:

• schema: The schema object returned from schema
• val: The input to validate. Can be a JsonNode or a JSON string.
• :validation-result (optional): Override for the function used to extract validation errors (defaults to this namespace's validation-result).

Returns: A sequence of error maps (see validation-result), or nil if valid.

Example: (validate myschema "{"foo":42}") (validate myschema my-jackson-json-node)

validate! clj

(validate! schema val & {:as opts})

Validates a value against a given JSON Schema and throws if invalid.

Arguments:

• schema (JsonSchema): A schema instance created by the schema function.
• val: The data to validate (can be a Jackson JsonNode or a JSON string).
• Optional keyword arguments:
  • :validation-result: Custom function to extract validation errors (defaults to this namespace's validation-result).

Behavior:

• If validation succeeds (no errors), returns nil.
• If validation fails, throws an ex-info exception with: :type --> :s-exp.legba.json-schema/failed-validation :errors --> Sequence of error maps (see validation-result). :val --> The input value that failed validation.

Example: (validate! myschema "{"name":42}") ; throws if invalid (validate! myschema my-jackson-json-node)

Useful for workflows where validation failure should abort or be handled via exception.

validation-result clj

(validation-result r)

Extracts and formats schema validation errors from a ValidationResult object.

Takes a NetworkNT ValidationResult and returns a vector of error maps, where each map contains:

• :path (string) JSON path of the error location
• :pointer (string) JSON pointer to the schema fragment
• :location (string) Instance location in the JSON document
• :detail (string) Validation error message/detail

Returns nil if there are no errors. Useful for turning validator output into a more consumable shape for clients, APIs, or error reporting.