types

package
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 Go to latest Published: Aug 10, 2026 License: MIT, BSD-3-Clause Imports: 15 Imported by: 0

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Index

Constants

This section is empty.

Variables

View Source 
var BoolKeyword = Keyword{
	Name:     "$bool",
	ArgType:  ArgTypeBool,
	Validate: validateBool,
}

BoolKeyword is not a real keyword, but is used to represent the special schema values "true" and "false".

View Source 
var ErrInvalidSchema = errors.New("invalid schema")

ErrInvalidSchema indicates that a schema document itself is invalid: unparseable JSON, a keyword argument of the wrong type, or an unresolvable reference. It is not a validation failure of an instance, and deliberately does not match the Motmedel client-input error categories: an invalid schema is a programming error.

View Source 
var SchemaKeyword = Keyword{
	Name:     "$schema",
	ArgType:  ArgTypeString,
	Validate: validateTrue,
}

SchemaKeyword is a keyword to hold the schema version.

Functions

func AddError 

func AddError(perr *error, err error, loc string)

AddError adds an error, which may be a validation error, to another error.

func AddValidationErrorStruct 

func AddValidationErrorStruct(perr *error, ve *ValidationError)

AddValidationErrorStruct adds a ValidationError to an existing error. The provided ve should already have basic fields populated. An existing error that is not a validation error is not disturbed.

func ClearVocabularies 

func ClearVocabularies()

ClearVocabularies discards the vocabulary registry. This is for tests.

func EnsureInstanceLocation 

func EnsureInstanceLocation(err error, ptr string) error

EnsureInstanceLocation sets InstanceLocation on validation errors if empty.

func IsValidationError 

func IsValidationError(err error) bool

IsValidationError reports whether err is a validation error. This deliberately matches only direct validation error values; validation errors are aggregated, not wrapped.

func NewValidateError 

func NewValidateError(err error, errs []*ValidationError) error

NewValidateError returns a *ValidateError wrapping err and collecting errs.

func RegisterVocabulary 

func RegisterVocabulary(v *Vocabulary, def bool)

RegisterVocabulary registers a vocabulary. The def argument is true for the default vocabulary. It's normally not necessary to call this; importing a JSON schema version package will register it.

func SetDefaultSchema 

func SetDefaultSchema(s string) error

SetDefaultSchema sets the default schema. The argument should be something like "draft7" or "draft2020-12". This is a global property, as there is no way to pass the desired value into the JSON decoder. Callers should use appropriate locking. This is mainly for tests.

func SetLoader 

func SetLoader(fn func(schemaID string, uri *url.URL) (*Schema, error)) func(string, *url.URL) (*Schema, error)

SetLoader sets a function to call when resolving a $ref to an external schema. This is a global property, as there is no way to pass the desired value into the JSON decoder. Callers should use appropriate locking.

Note that when unmarshaling user-written schemas, the loader function can be called with arbitrary URIs. It's probably unwise to simply call net/http.Get in all cases.

To fully support JSON schema cross references, the loader should call SchemaFromJSON. The caller will handle calling Schema.Resolve.

This returns the old loader function. The default loader function is nil, which will produce an error for a $ref to an external schema.

Types

type ArgType 

type ArgType int

ArgType is an enumeration of the possible schema part types. 

const (
	ArgTypeBool ArgType = iota + 1
	ArgTypeString
	ArgTypeStrings
	ArgTypeStringOrStrings
	ArgTypeInt
	ArgTypeFloat
	ArgTypeSchema
	ArgTypeSchemas
	ArgTypeMapSchema
	ArgTypeSchemaOrSchemas
	ArgTypeMapArrayOrSchema
	ArgTypeAny
)

type ArrayOrSchema 

type ArrayOrSchema struct {
	Array  []string // a zero-length slice is []string{}, not nil
	Schema *Schema
}

ArrayOrSchema is the element type of the PartMapArrayOrSchema map. Exactly one of the fields will be nil.

type Keyword 

type Keyword struct {
	// Name is the keyword, such as allOf, anyOf, and so forth.
	Name string

	// ArgType is the type of argument expected.
	ArgType ArgType

	// Validate is a function that checks whether the schema matches
	// the keyword. arg is the value from the schema, which is [Part.Value].
	// instance is the object to validate.
	//
	// The function returns an error if any.
	// A failure to validate will be type [*ValidationError]
	// or type [*ValidationErrors].
	// Any other error type indicates a problem with the schema itself,
	// not the instance.
	Validate func(arg PartValue, instance any, state *ValidationState) error

	// Generated is true if this keyword is not represented in JSON,
	// but is added to record additional information.
	// If this is true the keyword should be ignored by anything
	// that wants to treat the Schema as a JSON object.
	Generated bool
}

Keyword is a schema keyword.

func (Keyword) Equal 

func (k1 Keyword) Equal(k2 Keyword) bool

Equal reports whether two keywords are equal. This is for the benefit of comparison packages such as github.com/Motmedel/utils_go/pkg/testing/cmp, which use it instead of comparing the Validate function values.

type Part 

type Part struct {
	Keyword *Keyword
	Value   PartValue
}

Part is one part of a JSON schema. This is a keyword, such as "$id" or "properties", along with the value associated with that keyword in the schema.

func MakePart 

func MakePart(keyword *Keyword, value PartValue) Part

MakePart builds a Part.

type PartAny 

type PartAny struct {
	V any
}

PartAny is a schema part value that is an arbitrary type. For example, the schema keyword "$vocabulary" expects an object where each property is a URI. For example, the schema keyword "enum" expects an array, and matches an instance if the instance is equal to one of the elements in the array.

type PartBool 

type PartBool bool

PartBool is a schema part value that is a bool. This is a compact representation of a JSON schema. A value of true is the schema that matches every value. A value of false is the schema that matches no values.

type PartFloat 

type PartFloat float64

PartFloat is a schema part value that is a floating-point number. For example, the schema keyword "maximum" specifies the maximum value of a number.

type PartInt 

type PartInt int64

PartInt is a schema part value that is an integer. For example, the schema keyword "minLength" specifies the minimum length of a string.

type PartMapArrayOrSchema 

type PartMapArrayOrSchema map[string]ArrayOrSchema

PartMapArrayOrSchema is a map from strings to elements, where each element is either an array of strings or a schema. This is used for the draft7 "dependencies" keyword.

type PartMapSchema 

type PartMapSchema map[string]*Schema

PartMapSchema is a schema part value that is a map from strings to schemas. For example, the schema keyword "properties" has a mapping from field names to schemas, and matches an instance if the corresponding instance fields match the schemas.

type PartSchema 

type PartSchema struct {
	S *Schema
}

PartSchema is a schema part value that is a reference to a schema. For example, the schema keyword "not" refers to a schema; the instance matches if it does not match that schema.

type PartSchemaOrSchemas 

type PartSchemaOrSchemas struct {
	Schema  *Schema
	Schemas []*Schema
}

PartSchemaOrSchemas is either a single schema (like PartSchema) or a list of schemas (like PartSchemas). For example, the draft201909 keyword "items" takes either a single schema or a list of schemas. Exactly one of the fields will be nil.

type PartSchemas 

type PartSchemas []*Schema

PartSchemas is a schema part value that is a list of schemas. For example, the schema keyword "allOf" matches an instance if the instance matches each schema in the list.

type PartString 

type PartString string

PartString is a schema part value that is a string. For example, the schema keyword "pattern" has a string value that must be a regexp that must match the instance value.

type PartStringOrStrings 

type PartStringOrStrings struct {
	String  string
	Strings []string
}

PartStringOrStrings is a schema part that is either a single string or a list of strings. This is basically just for the "type" keyword, which takes either a single type string or an array of type strings. If the Strings is not nil, the String field must be the empty string.

type PartStrings 

type PartStrings []string

PartStrings is a schema part value that is a list of strings. For example, the schema keyword "required" takes a list of strings where each string is a property that the instance is required to have.

type PartValue 

type PartValue interface {
	// contains filtered or unexported methods
}

PartValue is the value of a JSON schema element. This is accessed via a type switch. The possible types are

type ResolveOpts 

type ResolveOpts struct {
	// The vocabulary to use.
	// This overrides anything recorded with the schema.
	Vocabulary *Vocabulary
	// URI of root of schema.
	// This is overridden by a $id keyword, if present.
	URI *url.URL
	// Load a remote reference, specifying the default schema.
	// This will be resolved by the resolver of the schema that
	// references it; no need for Loader to call (*Schema).Resolve.
	Loader func(schemaID string, uri *url.URL) (*Schema, error)
}

ResolveOpts is options to use when resolving the schema. These are all optional.

type Schema 

type Schema struct {
	// The different elements of this Schema.
	Parts []Part
}

Schema is a JSON schema. A JSON schema determines whether an instance is valid or not. Do not create values of this type directly. Instead, unmarshal from JSON or use a draft-specific Builder.

If you have an existing Schema, you can edit the Parts list, but you must call Schema.Finalize afterward. When adding a new Part it will help to use Vocabulary.Keywords; each supported JSON schema draft has a Vocabulary package variable. You can't add keywords that refer to other parts of the schema by name, such as $ref.

func SchemaFromJSON 

func SchemaFromJSON(schemaID string, uri *url.URL, v any) (*Schema, error)

SchemaFromJSON builds a Schema from a JSON value that has already been parsed. This could be used as something like 

var v any
if err := json.Unmarshal(data, &v); err != nil { ... }
s, err := schema.SchemaFromJSON(schemaID, uri, v)

This can be useful in cases where it's not clear whether the JSON encoding contains a schema or not.

The optional schemaID argument is something like [draft202012.SchemaID]. The optional uri is where the schema was loaded from.

It is normally necessary to call Resolve on the result.

func (*Schema) Children 

func (s *Schema) Children() iter.Seq2[string, *Schema]

Children returns an iterator over the immediate subschemas. The first iterator value is the name of the schema as used in a JSON pointer, the second is the schema itself.

func (*Schema) Clone 

func (s *Schema) Clone() *Schema

Clone returns a copy of a Schema.

func (*Schema) Finalize 

func (s *Schema) Finalize(v *Vocabulary)

Finalize sorts the schema keywords into the order required for validation. Normally there is no need to call this explicitly. It will be called automatically by a Builder or by the JSON unmarshaler.

func (*Schema) LookupKeyword 

func (s *Schema) LookupKeyword(keyword string) (PartValue, bool)

LookupKeyword returns the value associated with a keyword in the schema. The bool result reports whether the keyword is present at all.

func (*Schema) MarshalJSON 

func (s *Schema) MarshalJSON() ([]byte, error)

MarshalJSON marshals a Schema into JSON format. This implements encoding/json.Marshaler.

func (*Schema) MarshalJSONTo 

func (s *Schema) MarshalJSONTo(enc *jsontext.Encoder) error

MarshalJSONTo marshals a Schema into JSON format, writing the result to enc. This implements jsonv2.MarshalerTo.

func (*Schema) Resolve 

func (s *Schema) Resolve(opts *ResolveOpts) error

Resolve resolves references across a schema and its subschemas. Normally there is no need to call this explicitly. It will be called automatically by the JSON unmarshaler.

func (*Schema) String 

func (s *Schema) String() string

String returns a somewhat readable representation of a Schema. The format differs from JSON output, and also includes internal information not stored in JSON.

func (*Schema) UnmarshalJSON 

func (s *Schema) UnmarshalJSON(data []byte) error

UnmarshalJSON decodes the JSON representation of a Schema. This implements encoding/json.Unmarshaler.

func (*Schema) UnmarshalJSONFrom 

func (s *Schema) UnmarshalJSONFrom(dec *jsontext.Decoder) error

UnmarshalJSONFrom decodes the JSON representation of a Schema read from dec. This implements jsonv2.UnmarshalerFrom.

The schema is decoded directly from the JSON text, without building an intermediate representation.

func (*Schema) Validate 

func (s *Schema) Validate(instance any) error

Validate reports whether instance satisfies the schema. If it does, this returns nil. If it does not, this returns a *ValidateError that collects the individual *ValidationError values. A non-nil error of a different type indicates some error during validation processing.

func (*Schema) ValidateInPlaceSchema 

func (s *Schema) ValidateInPlaceSchema(instance any, state *ValidationState) error

ValidateInPlaceSchema reports whether instance satisfies schema, where schema is a subschema that is evaluated in the same context as the parent schema.

func (*Schema) ValidateSubSchema 

func (s *Schema) ValidateSubSchema(instance any, state *ValidationState) error

ValidateSubSchema reports whether instance satisfies schema, where schema is a sub-schema of some larger validation request. This is like Validate but also accepts the current validation state.

func (*Schema) ValidateWithOpts 

func (s *Schema) ValidateWithOpts(instance any, opts *ValidateOpts) error

ValidateWithOpts is like Validate but supports options.

type ValidateError 

type ValidateError struct {
	Errors []*ValidationError
	// contains filtered or unexported fields
}

ValidateError is the error returned by Schema.Validate when an instance fails validation. It wraps the underlying error and collects the individual validation errors.

func (*ValidateError) Is 

func (ve *ValidateError) Is(target error) bool

Is marks a ValidateError as a client-input validation failure, so that errors.Is(err, motmedelErrors.ErrValidationError) reports true.

func (*ValidateError) Unwrap 

func (ve *ValidateError) Unwrap() error

Unwrap returns the wrapped error.

type ValidateOpts 

type ValidateOpts struct {
	// Whether to modify the instance being validated by setting defaults.
	// If this is true, then defaults are applied when:
	//   - a "properties" keyword is applied to a map or a struct
	//   - a "prefixItems" keyword is applied to a slice or array
	//   - a "items" keyword with an array argument (pre draft2020-12)
	//     is applied to a slice or array.
	// In these cases, if the subschema has a "default" keyword,
	// and the value in question is the zero value of its type
	// (or, in the case of a map, is missing), then the instance
	// is modified to be set to the default.
	// Defaults are ignored for required properties,
	// as the user must supply them.
	//
	// This operation may panic if the instance can't be modified.
	//
	// The modification is made before validation;
	// if the default value is not permitted by the rest of
	// the schema, validation may fail.
	ApplyDefaults bool

	// Whether to validate the format keyword.
	// In order for this to be effective, the package
	// jsonschema/format must be blank imported;
	// by default the format keyword always matches.
	ValidateFormat bool
}

ValidateOpts describes validation options. These are uncommon so we use a separate method for them.

type ValidationError 

type ValidationError struct {
	// Basic output fields per JSON Schema output format (basic):
	// https://json-schema.org/draft/2020-12/json-schema-core.html#name-output-formats
	// These are the canonical fields consumers should use.
	Message          string `json:"error"`
	KeywordLocation  string `json:"keywordLocation"`
	InstanceLocation string `json:"instanceLocation"`
}

ValidationError is returned by a validation function when an instance fails validation.

func (*ValidationError) Error 

func (ve *ValidationError) Error() string

Error returns the error message that a user should see. This implements the error interface.

type ValidationErrors 

type ValidationErrors struct {
	Errs []*ValidationError
}

ValidationErrors is a collection of ValidationError values.

func (*ValidationErrors) Error 

func (ves *ValidationErrors) Error() string

Error returns the error message that a user should see. This implements the error interface.

type ValidationState 

type ValidationState struct {
	// The root of the Schema being validated.
	Root *Schema
	// The ValidationState attached to the root Schema,
	// for global information.
	RootState *ValidationState
	// The Schema being validated.
	Schema *Schema
	// The index in schema.Parts of the keyword currently being validated.
	Index int
	// Current URI, from $id keyword.
	URI *url.URL
	// Notes created during validation.
	Notes notes.Notes
	// Depth of tree when validating. Used to avoid infinite recursion.
	Depth int
	// Validation options. Nil for the defaults.
	Opts *ValidateOpts
	// For use by version-specific code.
	VersionData *any

	// InstancePath holds the JSON Pointer tokens to the current location
	// within the instance being validated.
	InstancePath []string
}

ValidationState is state we maintain while validating a schema. This does not apply to subschemas or parent schemas. This is exported for use by additional schema implementations. It is not expected to be used by code that just wants to validate a schema.

func (*ValidationState) Child 

func (vs *ValidationState) Child() (*ValidationState, error)

Child returns a new ValidationState that is a child of vs. This can be used to validate a subschema without changing the notes stored in vs.

func (*ValidationState) InstancePointer 

func (vs *ValidationState) InstancePointer() string

InstancePointer returns the current instance location as a JSON Pointer string starting with '#'.

func (*ValidationState) PopInstanceToken 

func (vs *ValidationState) PopInstanceToken()

PopInstanceToken removes the last token from the instance path.

func (*ValidationState) PushInstanceToken 

func (vs *ValidationState) PushInstanceToken(tok string)

PushInstanceToken appends a token to the instance path.

type Vocabulary 

type Vocabulary struct {
	// The name of this schema version, for messages.
	// Something like draft-2020-12.
	Name string
	// The URI that describes this schema version.
	// The value of the $schema keyword.
	// Something like "https://json-schema.org/draft/2020-12/schema".
	Schema string
	// The keywords of this schema version.
	Keywords map[string]*Keyword
	// A function that resolves references within a schema.
	Resolve func(*Schema, *ResolveOpts) error
	// The sorting function of this schema.
	// Used to sort the keywords of an instance of the schema.
	Cmp func(string, string) int
}

Vocabulary is a vocabulary type: a list of known keywords. Each schema version defines an instance of this type.

func DefaultVocabulary 

func DefaultVocabulary() *Vocabulary

DefaultVocabulary returns the default vocabulary, or nil if there isn't one.

func LookupVocabulary 

func LookupVocabulary(s string) *Vocabulary

LookupVocabulary returns a registered vocabulary, or nil if no vocabulary was registered under that name. It's normally not necessary to call this; instead use something like draft202012.Vocabulary.

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