cb95425f59
Uses json patch format for defaults: json patch (RFC 6902) makes it clearer in case of array contents. It is supported by nlohmann::json and can be applied with `patch` to fill up the json with defaults.
101 lines
2.8 KiB
C++
101 lines
2.8 KiB
C++
#include <iomanip>
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#include <iostream>
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#include <nlohmann/json-schema.hpp>
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using nlohmann::json;
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using nlohmann::json_schema::json_validator;
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// The schema is defined based upon a string literal
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static json person_schema = R"(
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{
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"$schema": "http://json-schema.org/draft-07/schema#",
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"title": "A person",
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"properties": {
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"name": {
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"description": "Name",
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"type": "string"
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},
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"age": {
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"description": "Age of the person",
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"type": "number",
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"minimum": 2,
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"maximum": 200
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},
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"address":{
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"type": "object",
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"properties":{
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"street":{
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"type": "string",
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"default": "Abbey Road"
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}
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}
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}
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},
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"required": [
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"name",
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"age"
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],
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"type": "object"
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}
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)"_json;
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// The people are defined with brace initialization
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static json bad_person = {{"age", 42}};
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static json good_person = {{"name", "Albert"}, {"age", 42}, {"address", {{"street", "Main Street"}}}};
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static json good_defaulted_person = {{"name", "Knut"}, {"age", 69}, {"address", {}}};
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int main()
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{
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/* json-parse the schema */
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json_validator validator; // create validator
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try {
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validator.set_root_schema(person_schema); // insert root-schema
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} catch (const std::exception &e) {
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std::cerr << "Validation of schema failed, here is why: " << e.what() << "\n";
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return EXIT_FAILURE;
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}
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/* json-parse the people - API of 1.0.0, default throwing error handler */
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for (auto &person : {bad_person, good_person, good_defaulted_person}) {
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std::cout << "About to validate this person:\n"
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<< std::setw(2) << person << std::endl;
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try {
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auto defaultPatch = validator.validate(person); // validate the document - uses the default throwing error-handler
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std::cout << "Validation succeeded\n";
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std::cout << "Patch with defaults: " << defaultPatch.dump(2) << std::endl;
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} catch (const std::exception &e) {
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std::cerr << "Validation failed, here is why: " << e.what() << "\n";
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}
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}
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/* json-parse the people - with custom error handler */
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class custom_error_handler : public nlohmann::json_schema::basic_error_handler
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{
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void error(const nlohmann::json::json_pointer &ptr, const json &instance, const std::string &message) override
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{
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nlohmann::json_schema::basic_error_handler::error(ptr, instance, message);
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std::cerr << "ERROR: '" << ptr << "' - '" << instance << "': " << message << "\n";
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}
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};
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for (auto &person : {bad_person, good_person}) {
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std::cout << "About to validate this person:\n"
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<< std::setw(2) << person << std::endl;
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custom_error_handler err;
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validator.validate(person, err); // validate the document
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if (err)
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std::cerr << "Validation failed\n";
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else
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std::cout << "Validation succeeded\n";
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}
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return EXIT_SUCCESS;
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}
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