json_schema.h File Reference

Functions for validating a string against a JSON Schema. More...

#include <cstddef>
#include <string>
#include "my_alloc.h"
#include "sql-common/json_error_handler.h"

Go to the source code of this file.

Classes
class	Json_schema_validation_report
	Json_schema_validation_report contains a more detailed report about a failed JSON Schema validation. More...
class	Json_schema_validator
	This is just a facade to the Json_schema_validator and it is used to hide the dependency on the rapidjson lib. More...

Functions
bool	is_valid_json_schema (const char *document_str, size_t document_length, const char *json_schema_str, size_t json_schema_length, const JsonSchemaErrorHandler &error_handler, const JsonErrorHandler &depth_handler, bool *is_valid, Json_schema_validation_report *report)
	This function will validate a JSON document against a JSON Schema using the validation provided by rapidjson. More...

Detailed Description

Functions for validating a string against a JSON Schema.

A JSON Schema is a way to describe the structure of a JSON document. The JSON Schema is a JSON document in itself, and allows you to define required names/attributes, data types etc. As an example, here is a minimal example of a JSON Schema describing that the JSON document MUST be an object:

{ "type": "object" }

If the JSON document to be validated is anything else than an object (array, scalar), the validation will fail.

This file contains one class for validation JSON documents against a cached JSON Schema, and free functions for validation any string input against a (unparsed) JSON Schema. We use the rapidjson library to do the actual validation with the following notable behaviors:

1) Remote references are not supported. If the user provides a JSON Schema with a remote reference, an error will be raised. 2) JSON Schema supports regex patterns, and we use std::regex as the regex engine. If an invalid regex pattern is provided in the JSON Schema, the regex pattern will be silently ignored. 3) rapidjson currently supports JSON Schema draft-v4, while there are newer versions available (as of writing, draft-v7 is the latest version).

Function Documentation

is_valid_json_schema()

bool is_valid_json_schema	(	const char *	document_str,
		size_t	document_length,
		const char *	json_schema_str,
		size_t	json_schema_length,
		const JsonSchemaErrorHandler &	error_handler,
		const JsonErrorHandler &	depth_handler,
		bool *	is_valid,
		Json_schema_validation_report *	report
	)

This function will validate a JSON document against a JSON Schema using the validation provided by rapidjson.

Parameters

	document_str	A pointer to the JSON document to be validated.
	document_length	The length of the JSON document to be validated.
	json_schema_str	A pointer to the JSON Schema.
	json_schema_length	The length of the JSON Schema.
	error_handler	Error handlers to be called when parsing errors occur.
	depth_handler	Pointer to a function that should handle error occurred when depth is exceeded.
[out]	is_valid	A variable containing the result of the validation. If true, the JSON document is valid according to the given JSON Schema.
[out]	report	A structure containing a detailed report from the validation. Is only populated if is_valid is set to "false". Can be nullptr if a detailed report isn't needed.

Return values

true	if anything went wrong (like parsing the JSON inputs). my_error has been called with an appropriate error message.
false	if the validation succeeded. The result of the validation can be found in the output variable "is_valid".