json-schema-validator/app/readme.cpp
Luke Kersting 8a7d1d3fde Adapt CMake project name to be coherent with nlohmann::json's naming
Now when json-schema-validator is installed CMake config files are installed in the lib/cmake/json-schema-validator directory.
The install json-schema-validatorTargets.cmake file properly imports the json-hpp and json-schema-validator libraries.
The install json-schema-validatorConfig.cmake file is used by CMake find_package function to include the json-schema-validatorTargets.cmake file and to set the variable JSON_SCHEMA_VALIDATOR_INCLUDE_DIRS to the install include directory.
To use find_package to find the json-schema-validator simply include.
A new test (test_cmake_install) has been added.

When NLohmann's JSON is install with CMake, it follows a certain
naming convention.

As we learned to do proper CMake-install thanks to @lkersting's work
this project now adapts to the way NLohmann is doing it. Namely:

- json-schema.hpp is now located (and installed)
  in a nlohmann/-subdirectory
- the CMake library and project's name is now
  nlohmann_json_schema_validator

Instead of doing non-standard acrobatics to find the json.hpp
now find_package is used in order to find NLohmann's package

Co-Authored-By: Patrick Boettcher <p@yai.se>
2019-12-05 11:12:23 +01:00

91 lines
2.4 KiB
C++

#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;
}