AlterSchema

A growing collection of JSON Schema transformation rules. More...

Classes
class	sourcemeta::blaze::SchemaRule
class	sourcemeta::blaze::SchemaRuleMissingNameError
class	sourcemeta::blaze::SchemaRuleInvalidNameError
class	sourcemeta::blaze::SchemaRuleInvalidNamePatternError
class	sourcemeta::blaze::SchemaAbortError
class	sourcemeta::blaze::SchemaBrokenReferenceError
class	sourcemeta::blaze::SchemaTransformRuleProcessedTwiceError
class	sourcemeta::blaze::SchemaTransformRule
class	sourcemeta::blaze::SchemaTransformer

Enumerations
enum class	sourcemeta::blaze::AlterSchemaMode : std::uint8_t { AlterSchemaMode::Linter }

Functions
SOURCEMETA_BLAZE_ALTERSCHEMA_EXPORT auto	sourcemeta::blaze::add (SchemaTransformer &bundle, const AlterSchemaMode mode) -> void
SOURCEMETA_BLAZE_ALTERSCHEMA_EXPORT auto	sourcemeta::blaze::wrap (const sourcemeta::core::JSON &schema, const sourcemeta::core::SchemaFrame &frame, const sourcemeta::core::SchemaFrame::Location &location, const sourcemeta::core::SchemaWalker &walker, const sourcemeta::core::SchemaResolver &resolver, sourcemeta::core::WeakPointer &base) -> sourcemeta::core::JSON

Detailed Description

A growing collection of JSON Schema transformation rules.

This functionality is included as follows:

#include <sourcemeta/blaze/alterschema.h>

---

Class Documentation

sourcemeta::blaze::SchemaRule

class sourcemeta::blaze::SchemaRule

A linter rule driven by a JSON Schema. By default, every subschema in the document under inspection is validated as a JSON instance against the provided rule schema, though a rule may be scoped to only run against the document root. When a subschema does not conform, the rule fires and reports the validation errors. The rule name is extracted from the title keyword of the rule schema, and the rule description from the description keyword. The title must consist only of lowercase ASCII letters, digits, underscores, or slashes.

Inheritance diagram for sourcemeta::blaze::SchemaRule:

Public Types
enum class	Scope : std::uint8_t { All , TopLevel }
	The locations of the schema that the rule applies to. More...
using	mutates = std::false_type
using	reframe_after_transform = std::false_type
Public Member Functions
	SchemaRule (const sourcemeta::core::JSON &schema, const sourcemeta::core::SchemaWalker &walker, const sourcemeta::core::SchemaResolver &resolver, const Compiler &compiler, const std::string_view default_dialect="", const std::optional< Tweaks > &tweaks=std::nullopt, const Scope scope=Scope::All)
auto	condition (const sourcemeta::core::JSON &, const sourcemeta::core::JSON &, const sourcemeta::core::SchemaVocabularies &, const sourcemeta::core::SchemaFrame &, const sourcemeta::core::SchemaFrame::Location &, const sourcemeta::core::SchemaWalker &, const sourcemeta::core::SchemaResolver &) const -> SchemaTransformRule::Result override
Public Member Functions inherited from sourcemeta::blaze::SchemaTransformRule
	SchemaTransformRule (const std::string_view name, const std::string_view message)
	SchemaTransformRule (const SchemaTransformRule &)=delete
	SchemaTransformRule (SchemaTransformRule &&)=delete
auto	operator= (const SchemaTransformRule &) -> SchemaTransformRule &=delete
auto	operator= (SchemaTransformRule &&) -> SchemaTransformRule &=delete
auto	operator== (const SchemaTransformRule &other) const -> bool
	Compare a rule against another rule.
auto	name () const noexcept -> std::string_view
	Fetch the name of a rule.
auto	message () const noexcept -> std::string_view
	Fetch the message of a rule.
auto	check (const sourcemeta::core::JSON &schema, const sourcemeta::core::JSON &root, const sourcemeta::core::SchemaVocabularies &vocabularies, const sourcemeta::core::SchemaWalker &walker, const sourcemeta::core::SchemaResolver &resolver, const sourcemeta::core::SchemaFrame &frame, const sourcemeta::core::SchemaFrame::Location &location, const sourcemeta::core::JSON::String &exclude_keyword) const -> Result
	Check if the rule applies to a schema.
virtual auto	rereference (const std::string_view reference, const sourcemeta::core::Pointer &origin, const sourcemeta::core::Pointer &target, const sourcemeta::core::Pointer &current) const -> sourcemeta::core::Pointer
virtual auto	condition (const sourcemeta::core::JSON &schema, const sourcemeta::core::JSON &root, const sourcemeta::core::SchemaVocabularies &vocabularies, const sourcemeta::core::SchemaFrame &frame, const sourcemeta::core::SchemaFrame::Location &location, const sourcemeta::core::SchemaWalker &walker, const sourcemeta::core::SchemaResolver &resolver) const -> Result=0
	The rule condition.
virtual auto	transform (sourcemeta::core::JSON &schema, const Result &result) const -> void

Member Enumeration Documentation

Scope

enum class sourcemeta::blaze::SchemaRule::Scope : std::uint8_t

strong

The locations of the schema that the rule applies to.

Enumerator
All	Every subschema of the document under inspection.
TopLevel	Only the document root.

sourcemeta::blaze::SchemaRuleMissingNameError

class sourcemeta::blaze::SchemaRuleMissingNameError

An error that represents a missing schema rule name

Inheritance diagram for sourcemeta::blaze::SchemaRuleMissingNameError:

Public Member Functions
auto	what () const noexcept -> const char *override

sourcemeta::blaze::SchemaRuleInvalidNameError

class sourcemeta::blaze::SchemaRuleInvalidNameError

An error that represents an invalid schema rule name. The name must consist only of lowercase ASCII letters, digits, underscores, or slashes.

Inheritance diagram for sourcemeta::blaze::SchemaRuleInvalidNameError:

Public Member Functions
	SchemaRuleInvalidNameError (const std::string_view identifier, const char *message)
	SchemaRuleInvalidNameError (const std::string_view identifier, std::string message)=delete
	SchemaRuleInvalidNameError (const std::string_view identifier, std::string &&message)=delete
	SchemaRuleInvalidNameError (const std::string_view identifier, std::string_view message)=delete
auto	what () const noexcept -> const char *override
auto	identifier () const noexcept -> const std::string &

sourcemeta::blaze::SchemaRuleInvalidNamePatternError

class sourcemeta::blaze::SchemaRuleInvalidNamePatternError

An error that represents a schema rule name that does not match the required pattern

Inheritance diagram for sourcemeta::blaze::SchemaRuleInvalidNamePatternError:

Public Member Functions
	SchemaRuleInvalidNamePatternError (const std::string_view identifier, const std::string_view regex)
auto	what () const noexcept -> const char *override
auto	identifier () const noexcept -> const std::string &
auto	regex () const noexcept -> const std::string &

sourcemeta::blaze::SchemaAbortError

class sourcemeta::blaze::SchemaAbortError

An error that represents that a schema operation cannot continue

Inheritance diagram for sourcemeta::blaze::SchemaAbortError:

Public Member Functions
	SchemaAbortError (const char *message)
	SchemaAbortError (std::string message)=delete
	SchemaAbortError (std::string &&message)=delete
	SchemaAbortError (std::string_view message)=delete
auto	what () const noexcept -> const char *override

sourcemeta::blaze::SchemaBrokenReferenceError

class sourcemeta::blaze::SchemaBrokenReferenceError

An error that represents a broken schema reference after transformation

Inheritance diagram for sourcemeta::blaze::SchemaBrokenReferenceError:

Public Member Functions
	SchemaBrokenReferenceError (const std::string_view identifier, sourcemeta::core::Pointer schema_location, const char *message)
auto	what () const noexcept -> const char *override
auto	identifier () const noexcept -> std::string_view
auto	location () const noexcept -> const sourcemeta::core::Pointer &

sourcemeta::blaze::SchemaTransformRuleProcessedTwiceError

class sourcemeta::blaze::SchemaTransformRuleProcessedTwiceError

An error that signifies that a transform rule was applied more than once

Inheritance diagram for sourcemeta::blaze::SchemaTransformRuleProcessedTwiceError:

Public Member Functions
	SchemaTransformRuleProcessedTwiceError (const std::string_view name, sourcemeta::core::Pointer location)
auto	what () const noexcept -> const char *override
auto	name () const noexcept -> std::string_view
auto	location () const noexcept -> const sourcemeta::core::Pointer &

sourcemeta::blaze::SchemaTransformRule

class sourcemeta::blaze::SchemaTransformRule

A class that represents a transformation rule. Clients of this class are expected to subclass and implement their own condition and transformation methods.

Inheritance diagram for sourcemeta::blaze::SchemaTransformRule:

Public Member Functions
	SchemaTransformRule (const std::string_view name, const std::string_view message)
	SchemaTransformRule (const SchemaTransformRule &)=delete
	SchemaTransformRule (SchemaTransformRule &&)=delete
auto	operator= (const SchemaTransformRule &) -> SchemaTransformRule &=delete
auto	operator= (SchemaTransformRule &&) -> SchemaTransformRule &=delete
auto	operator== (const SchemaTransformRule &other) const -> bool
	Compare a rule against another rule.
auto	name () const noexcept -> std::string_view
	Fetch the name of a rule.
auto	message () const noexcept -> std::string_view
	Fetch the message of a rule.
auto	check (const sourcemeta::core::JSON &schema, const sourcemeta::core::JSON &root, const sourcemeta::core::SchemaVocabularies &vocabularies, const sourcemeta::core::SchemaWalker &walker, const sourcemeta::core::SchemaResolver &resolver, const sourcemeta::core::SchemaFrame &frame, const sourcemeta::core::SchemaFrame::Location &location, const sourcemeta::core::JSON::String &exclude_keyword) const -> Result
	Check if the rule applies to a schema.
virtual auto	rereference (const std::string_view reference, const sourcemeta::core::Pointer &origin, const sourcemeta::core::Pointer &target, const sourcemeta::core::Pointer &current) const -> sourcemeta::core::Pointer
virtual auto	condition (const sourcemeta::core::JSON &schema, const sourcemeta::core::JSON &root, const sourcemeta::core::SchemaVocabularies &vocabularies, const sourcemeta::core::SchemaFrame &frame, const sourcemeta::core::SchemaFrame::Location &location, const sourcemeta::core::SchemaWalker &walker, const sourcemeta::core::SchemaResolver &resolver) const -> Result=0
	The rule condition.
virtual auto	transform (sourcemeta::core::JSON &schema, const Result &result) const -> void

Member Function Documentation

rereference()

virtual auto sourcemeta::blaze::SchemaTransformRule::rereference ( const std::string_view reference, const sourcemeta::core::Pointer & origin, const sourcemeta::core::Pointer & target, const sourcemeta::core::Pointer & current ) const->sourcemeta::core::Pointer

nodiscardvirtual

A method to optionally fix any reference location that was affected by the transformation

transform()

virtual auto sourcemeta::blaze::SchemaTransformRule::transform ( sourcemeta::core::JSON & schema, const Result & result ) const->void

virtual

The rule transformation. If this virtual method is not overriden, then the rule is considered to not mutate the schema

sourcemeta::blaze::SchemaTransformer

class sourcemeta::blaze::SchemaTransformer

You can use this class to perform top-down transformations on subschemas given a set of rules. Every registered rule is applied to every subschema of the passed schema until no longer of them applies.

Public Types
using	Callback
	The callback that is called whenever the condition of a rule holds true.
using	Framer
Public Member Functions
template<std::derived_from< SchemaTransformRule > T, typename... Args>
auto	add (Args &&...args) -> std::string_view
auto	remove (const std::string_view name) -> bool
	Remove a rule from the bundle.
auto	apply (sourcemeta::core::JSON &schema, const sourcemeta::core::SchemaWalker &walker, const sourcemeta::core::SchemaResolver &resolver, const Callback &callback, std::string_view default_dialect="", std::string_view default_id="", const sourcemeta::core::JSON::String &exclude_keyword="") const -> std::pair< bool, std::uint8_t >
	Apply the bundle of rules to a schema.
auto	apply (sourcemeta::core::JSON &document, const Framer &framer, const sourcemeta::core::SchemaWalker &walker, const sourcemeta::core::SchemaResolver &resolver, const Callback &callback, const sourcemeta::core::JSON::String &exclude_keyword="") const -> std::pair< bool, std::uint8_t >
auto	check (const sourcemeta::core::JSON &schema, const sourcemeta::core::SchemaWalker &walker, const sourcemeta::core::SchemaResolver &resolver, const Callback &callback, std::string_view default_dialect="", std::string_view default_id="", const sourcemeta::core::JSON::String &exclude_keyword="") const -> std::pair< bool, std::uint8_t >
auto	check (const sourcemeta::core::JSON &document, const sourcemeta::core::SchemaFrame &frame, const sourcemeta::core::SchemaWalker &walker, const sourcemeta::core::SchemaResolver &resolver, const Callback &callback, const sourcemeta::core::JSON::String &exclude_keyword="") const -> std::pair< bool, std::uint8_t >
auto	begin () const -> auto
auto	end () const -> auto

Member Typedef Documentation

Callback

using sourcemeta::blaze::SchemaTransformer::Callback

Initial value:

 std::function<void(
      const sourcemeta::core::Pointer &, const std::string_view,
      const std::string_view, const SchemaTransformRule::Result &, const bool)>

The callback that is called whenever the condition of a rule holds true.

Framer

using sourcemeta::blaze::SchemaTransformer::Framer

Initial value:

 std::function<const sourcemeta::core::SchemaFrame &(
      const sourcemeta::core::JSON &)>

Frame a document as it currently stands, in References mode. Applying rules calls it again whenever a transformation needs a new frame, so the frame it returns only has to remain valid until the next call

Member Function Documentation

add()

template<std::derived_from< SchemaTransformRule > T, typename... Args>

auto sourcemeta::blaze::SchemaTransformer::add ( Args &&... args ) ->std::string_view

inline

Add a rule to the bundle. Rules are evaluated in the order they are added. It is the caller's responsibility to not add duplicate rules.

apply()

auto sourcemeta::blaze::SchemaTransformer::apply ( sourcemeta::core::JSON & document, const Framer & framer, const sourcemeta::core::SchemaWalker & walker, const sourcemeta::core::SchemaResolver & resolver, const Callback & callback, const sourcemeta::core::JSON::String & exclude_keyword = "" ) const->std::pair< bool, std::uint8_t >

nodiscard

Apply the bundle of rules to every subschema that a framer locates within a document

check() [1/2]

auto sourcemeta::blaze::SchemaTransformer::check ( const sourcemeta::core::JSON & document, const sourcemeta::core::SchemaFrame & frame, const sourcemeta::core::SchemaWalker & walker, const sourcemeta::core::SchemaResolver & resolver, const Callback & callback, const sourcemeta::core::JSON::String & exclude_keyword = "" ) const->std::pair< bool, std::uint8_t >

nodiscard

Report back the rules from the bundle that need to be applied to every subschema that a frame locates within a document

check() [2/2]

auto sourcemeta::blaze::SchemaTransformer::check ( const sourcemeta::core::JSON & schema, const sourcemeta::core::SchemaWalker & walker, const sourcemeta::core::SchemaResolver & resolver, const Callback & callback, std::string_view default_dialect = "", std::string_view default_id = "", const sourcemeta::core::JSON::String & exclude_keyword = "" ) const->std::pair< bool, std::uint8_t >

nodiscard

Report back the rules from the bundle that need to be applied to a schema

Enumeration Type Documentation

AlterSchemaMode

enum class sourcemeta::blaze::AlterSchemaMode : std::uint8_t

strong

The category of a built-in transformation rule

Enumerator
Linter	Rules that simplify the given schema for both human readability and performance

Function Documentation

add()

SOURCEMETA_BLAZE_ALTERSCHEMA_EXPORT auto sourcemeta::blaze::add	(	SchemaTransformer &	bundle,
		const AlterSchemaMode	mode )->void

Add a set of built-in schema transformation rules given a category. For example:

#include <sourcemeta/core/jsonschema.h>
#include <sourcemeta/blaze/alterschema.h>
 
sourcemeta::blaze::SchemaTransformer bundle;
 
sourcemeta::blaze::add(bundle,
  sourcemeta::blaze::AlterSchemaMode::Linter);
 
auto schema = sourcemeta::core::parse_json(R"JSON({
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "foo": 1,
  "items": {
    "type": "string",
    "foo": 2
  }
})JSON");
 
const auto result{bundle.apply(schema,
  sourcemeta::core::schema_walker,
  sourcemeta::core::schema_resolver,
  [](const auto &pointer,
     const auto &name,
     const auto &message,
     const auto &outcome,
     const auto dismissed) {
    // Do something with the information
  })};

wrap()

SOURCEMETA_BLAZE_ALTERSCHEMA_EXPORT auto sourcemeta::blaze::wrap	(	const sourcemeta::core::JSON &	schema,
		const sourcemeta::core::SchemaFrame &	frame,
		const sourcemeta::core::SchemaFrame::Location &	location,
		const sourcemeta::core::SchemaWalker &	walker,
		const sourcemeta::core::SchemaResolver &	resolver,
		sourcemeta::core::WeakPointer &	base )->sourcemeta::core::JSON

Wrap a schema to only access one of its subschemas. This is useful if you want to perform validation on only a specific part of the schema without having to reinvent the wheel. For example:

#include <sourcemeta/core/json.h>
#include <sourcemeta/core/jsonpointer.h>
#include <sourcemeta/core/jsonschema.h>
#include <sourcemeta/blaze/alterschema.h>
#include <iostream>
 
const sourcemeta::core::JSON document =
    sourcemeta::core::parse_json(R"JSON({
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "items": { "type": "string" }
})JSON");
 
const sourcemeta::core::SchemaFrame frame{
    sourcemeta::core::SchemaFrame::Mode::References, document,
    sourcemeta::core::schema_walker, sourcemeta::core::schema_resolver};
 
const sourcemeta::core::Pointer pointer{"items"};
const auto location{frame.traverse(
    sourcemeta::core::to_weak_pointer(pointer),
    sourcemeta::core::SchemaFrame::LocationType::Subschema)};
 
sourcemeta::core::WeakPointer base;
const sourcemeta::core::JSON result =
  sourcemeta::blaze::wrap(document, frame, location.value().get(),
    sourcemeta::core::schema_walker, sourcemeta::core::schema_resolver,
    base);
 
sourcemeta::core::prettify(result, std::cerr);
std::cerr << "\n";