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// Schema Validator example
// The example validates JSON text from stdin with a JSON schema specified in the argument.
#include "rapidjson/error/en.h"
#include "rapidjson/filereadstream.h"
#include "rapidjson/schema.h"
#include "rapidjson/stringbuffer.h"
#include "rapidjson/prettywriter.h"
#include <string>
#include <iostream>
#include <sstream>
using namespace rapidjson;
typedef GenericValue<UTF8<>, CrtAllocator > ValueType;
// Forward ref
static void CreateErrorMessages(const ValueType& errors, size_t depth, const char* context);
// Convert GenericValue to std::string
static std::string GetString(const ValueType& val) {
std::ostringstream s;
if (val.IsString())
s << val.GetString();
else if (val.IsDouble())
s << val.GetDouble();
else if (val.IsUint())
s << val.GetUint();
else if (val.IsInt())
s << val.GetInt();
else if (val.IsUint64())
s << val.GetUint64();
else if (val.IsInt64())
s << val.GetInt64();
else if (val.IsBool() && val.GetBool())
s << "true";
else if (val.IsBool())
s << "false";
else if (val.IsFloat())
s << val.GetFloat();
return s.str();}
// Create the error message for a named error
// The error object can either be empty or contain at least member properties:
// {"errorCode": <code>, "instanceRef": "<pointer>", "schemaRef": "<pointer>" }
// Additional properties may be present for use as inserts.
// An "errors" property may be present if there are child errors.
static void HandleError(const char* errorName, const ValueType& error, size_t depth, const char* context) {
if (!error.ObjectEmpty()) {
// Get error code and look up error message text (English)
int code = error["errorCode"].GetInt();
std::string message(GetValidateError_En(static_cast<ValidateErrorCode>(code)));
// For each member property in the error, see if its name exists as an insert in the error message and if so replace with the stringified property value
// So for example - "Number '%actual' is not a multiple of the 'multipleOf' value '%expected'." - we would expect "actual" and "expected" members.
for (ValueType::ConstMemberIterator insertsItr = error.MemberBegin();
insertsItr != error.MemberEnd(); ++insertsItr) {
std::string insertName("%");
insertName += insertsItr->name.GetString(); // eg "%actual"
size_t insertPos = message.find(insertName);
if (insertPos != std::string::npos) {
std::string insertString("");
const ValueType &insert = insertsItr->value;
if (insert.IsArray()) {
// Member is an array so create comma-separated list of items for the insert string
for (ValueType::ConstValueIterator itemsItr = insert.Begin(); itemsItr != insert.End(); ++itemsItr) {
if (itemsItr != insert.Begin()) insertString += ",";
insertString += GetString(*itemsItr);
} else {
insertString += GetString(insert);
message.replace(insertPos, insertName.length(), insertString);
// Output error message, references, context
std::string indent(depth * 2, ' ');
std::cout << indent << "Error Name: " << errorName << std::endl;
std::cout << indent << "Message: " << message.c_str() << std::endl;
std::cout << indent << "Instance: " << error["instanceRef"].GetString() << std::endl;
std::cout << indent << "Schema: " << error["schemaRef"].GetString() << std::endl;
if (depth > 0) std::cout << indent << "Context: " << context << std::endl;
std::cout << std::endl;
// If child errors exist, apply the process recursively to each error structure.
// This occurs for "oneOf", "allOf", "anyOf" and "dependencies" errors, so pass the error name as context.
if (error.HasMember("errors")) {
const ValueType &childErrors = error["errors"];
if (childErrors.IsArray()) {
// Array - each item is an error structure - example
// "anyOf": {"errorCode": ..., "errors":[{"pattern": {"errorCode\": ...\"}}, {"pattern": {"errorCode\": ...}}]
for (ValueType::ConstValueIterator errorsItr = childErrors.Begin();
errorsItr != childErrors.End(); ++errorsItr) {
CreateErrorMessages(*errorsItr, depth, errorName);
} else if (childErrors.IsObject()) {
// Object - each member is an error structure - example
// "dependencies": {"errorCode": ..., "errors": {"address": {"required": {"errorCode": ...}}, "name": {"required": {"errorCode": ...}}}
for (ValueType::ConstMemberIterator propsItr = childErrors.MemberBegin();
propsItr != childErrors.MemberEnd(); ++propsItr) {
CreateErrorMessages(propsItr->value, depth, errorName);
// Create error message for all errors in an error structure
// Context is used to indicate whether the error structure has a parent 'dependencies', 'allOf', 'anyOf' or 'oneOf' error
static void CreateErrorMessages(const ValueType& errors, size_t depth = 0, const char* context = 0) {
// Each member property contains one or more errors of a given type
for (ValueType::ConstMemberIterator errorTypeItr = errors.MemberBegin(); errorTypeItr != errors.MemberEnd(); ++errorTypeItr) {
const char* errorName = errorTypeItr->name.GetString();
const ValueType& errorContent = errorTypeItr->value;
if (errorContent.IsArray()) {
// Member is an array where each item is an error - eg "type": [{"errorCode": ...}, {"errorCode": ...}]
for (ValueType::ConstValueIterator contentItr = errorContent.Begin(); contentItr != errorContent.End(); ++contentItr) {
HandleError(errorName, *contentItr, depth, context);
} else if (errorContent.IsObject()) {
// Member is an object which is a single error - eg "type": {"errorCode": ... }
HandleError(errorName, errorContent, depth, context);
int main(int argc, char *argv[]) {
if (argc != 2) {
fprintf(stderr, "Usage: schemavalidator schema.json < input.json\n");
// Read a JSON schema from file into Document
Document d;
char buffer[4096];
FILE *fp = fopen(argv[1], "r");
if (!fp) {
printf("Schema file '%s' not found\n", argv[1]);
return -1;
FileReadStream fs(fp, buffer, sizeof(buffer));
if (d.HasParseError()) {
fprintf(stderr, "Schema file '%s' is not a valid JSON\n", argv[1]);
fprintf(stderr, "Error(offset %u): %s\n",
// Then convert the Document into SchemaDocument
SchemaDocument sd(d);
// Use reader to parse the JSON in stdin, and forward SAX events to validator
SchemaValidator validator(sd);
Reader reader;
FileReadStream is(stdin, buffer, sizeof(buffer));
if (!reader.Parse(is, validator) && reader.GetParseErrorCode() != kParseErrorTermination) {
// Schema validator error would cause kParseErrorTermination, which will handle it in next step.
fprintf(stderr, "Input is not a valid JSON\n");
fprintf(stderr, "Error(offset %u): %s\n",
// Check the validation result
if (validator.IsValid()) {
printf("Input JSON is valid.\n");
else {
printf("Input JSON is invalid.\n");
StringBuffer sb;
fprintf(stderr, "Invalid schema: %s\n", sb.GetString());
fprintf(stderr, "Invalid keyword: %s\n", validator.GetInvalidSchemaKeyword());
fprintf(stderr, "Invalid code: %d\n", validator.GetInvalidSchemaCode());
fprintf(stderr, "Invalid message: %s\n", GetValidateError_En(validator.GetInvalidSchemaCode()));
fprintf(stderr, "Invalid document: %s\n", sb.GetString());
// Detailed violation report is available as a JSON value
PrettyWriter<StringBuffer> w(sb);
fprintf(stderr, "Error report:\n%s\n", sb.GetString());