#include <iostream>
#include <iomanip>
#include <nlohmann/json-schema.hpp>
using nlohmann::json;
using nlohmann::json_schema::json_validator;
// The schema is defined based upon a string literal
static json person_schema = R"(
{
"$schema": "http://json-schema.org/draft-07/schema#",
"title": "A person",
"properties": {
"name": {
"description": "Name",
"type": "string"
},
"age": {
"description": "Age of the person",
"type": "number",
"minimum": 2,
"maximum": 200
}
},
"required": [
"name",
"age"
],
"type": "object"
}
)"_json;
// The people are defined with brace initialization
static json bad_person = {{"age", 42}};
static json good_person = {{"name", "Albert"}, {"age", 42}};
int main()
{
/* json-parse the schema */
json_validator validator; // create validator
try {
validator.set_root_schema(person_schema); // insert root-schema
} catch (const std::exception &e) {
std::cerr << "Validation of schema failed, here is why: " << e.what() << "\n";
return EXIT_FAILURE;
}
/* json-parse the people - API of 1.0.0, default throwing error handler */
for (auto &person : {bad_person, good_person}) {
std::cout << "About to validate this person:\n"
<< std::setw(2) << person << std::endl;
try {
validator.validate(person); // validate the document - uses the default throwing error-handler
std::cout << "Validation succeeded\n";
} catch (const std::exception &e) {
std::cerr << "Validation failed, here is why: " << e.what() << "\n";
}
}
/* json-parse the people - with custom error handler */
class custom_error_handler : public nlohmann::json_schema::basic_error_handler
{
void error(const nlohmann::json::json_pointer &ptr, const json &instance, const std::string &message) override
{
nlohmann::json_schema::basic_error_handler::error(ptr, instance, message);
std::cerr << "ERROR: '" << ptr << "' - '" << instance << "': " << message << "\n";
}
};
for (auto &person : {bad_person, good_person}) {
std::cout << "About to validate this person:\n"
<< std::setw(2) << person << std::endl;
custom_error_handler err;
validator.validate(person, err); // validate the document
if (err)
std::cerr << "Validation failed\n";
else
std::cout << "Validation succeeded\n";
}
return EXIT_SUCCESS;
}
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