/* __ _____ _____ _____ __| | __| | | | JSON for Modern C++ (test suite) | | |__ | | | | | | version 2.0.8 |_____|_____|_____|_|___| https://github.com/nlohmann/json Licensed under the MIT License . Copyright (c) 2013-2016 Niels Lohmann . Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #include "catch.hpp" #include "json.hpp" using nlohmann::json; #include #include #include #include #include TEST_CASE("README", "[hide]") { { // redirect std::cout for the README file auto old_cout_buffer = std::cout.rdbuf(); std::ostringstream new_stream; std::cout.rdbuf(new_stream.rdbuf()); { // create an empty structure (null) json j; // add a number that is stored as double (note the implicit conversion of j to an object) j["pi"] = 3.141; // add a Boolean that is stored as bool j["happy"] = true; // add a string that is stored as std::string j["name"] = "Niels"; // add another null object by passing nullptr j["nothing"] = nullptr; // add an object inside the object j["answer"]["everything"] = 42; // add an array that is stored as std::vector (using an initializer list) j["list"] = { 1, 0, 2 }; // add another object (using an initializer list of pairs) j["object"] = { {"currency", "USD"}, {"value", 42.99} }; // instead, you could also write (which looks very similar to the JSON above) json j2 = { {"pi", 3.141}, {"happy", true}, {"name", "Niels"}, {"nothing", nullptr}, { "answer", { {"everything", 42} } }, {"list", {1, 0, 2}}, { "object", { {"currency", "USD"}, {"value", 42.99} } } }; } { // ways to express the empty array [] json empty_array_implicit = {{}}; json empty_array_explicit = json::array(); // a way to express the empty object {} json empty_object_explicit = json::object(); // a way to express an _array_ of key/value pairs [["currency", "USD"], ["value", 42.99]] json array_not_object = { json::array({"currency", "USD"}), json::array({"value", 42.99}) }; } { // create object from string literal json j = "{ \"happy\": true, \"pi\": 3.141 }"_json; // or even nicer with a raw string literal auto j2 = R"( { "happy": true, "pi": 3.141 } )"_json; // or explicitly auto j3 = json::parse("{ \"happy\": true, \"pi\": 3.141 }"); // explicit conversion to string std::string s = j.dump(); // {\"happy\":true,\"pi\":3.141} // serialization with pretty printing // pass in the amount of spaces to indent std::cout << j.dump(4) << std::endl; // { // "happy": true, // "pi": 3.141 // } std::cout << std::setw(2) << j << std::endl; } { // create an array using push_back json j; j.push_back("foo"); j.push_back(1); j.push_back(true); // iterate the array for (json::iterator it = j.begin(); it != j.end(); ++it) { std::cout << *it << '\n'; } // range-based for for (auto element : j) { std::cout << element << '\n'; } // getter/setter const std::string tmp = j[0]; j[1] = 42; bool foo = j.at(2); // other stuff j.size(); // 3 entries j.empty(); // false j.type(); // json::value_t::array j.clear(); // the array is empty again // comparison j == "[\"foo\", 1, true]"_json; // true // create an object json o; o["foo"] = 23; o["bar"] = false; o["baz"] = 3.141; // find an entry if (o.find("foo") != o.end()) { // there is an entry with key "foo" } } { std::vector c_vector {1, 2, 3, 4}; json j_vec(c_vector); // [1, 2, 3, 4] std::deque c_deque {1.2f, 2.3f, 3.4f, 5.6f}; json j_deque(c_deque); // [1.2, 2.3, 3.4, 5.6] std::list c_list {true, true, false, true}; json j_list(c_list); // [true, true, false, true] std::forward_list c_flist {12345678909876, 23456789098765, 34567890987654, 45678909876543}; json j_flist(c_flist); // [12345678909876, 23456789098765, 34567890987654, 45678909876543] std::array c_array {{1, 2, 3, 4}}; json j_array(c_array); // [1, 2, 3, 4] std::set c_set {"one", "two", "three", "four", "one"}; json j_set(c_set); // only one entry for "one" is used // ["four", "one", "three", "two"] std::unordered_set c_uset {"one", "two", "three", "four", "one"}; json j_uset(c_uset); // only one entry for "one" is used // maybe ["two", "three", "four", "one"] std::multiset c_mset {"one", "two", "one", "four"}; json j_mset(c_mset); // both entries for "one" are used // maybe ["one", "two", "one", "four"] std::unordered_multiset c_umset {"one", "two", "one", "four"}; json j_umset(c_umset); // both entries for "one" are used // maybe ["one", "two", "one", "four"] } { std::map c_map { {"one", 1}, {"two", 2}, {"three", 3} }; json j_map(c_map); // {"one": 1, "two": 2, "three": 3} std::unordered_map c_umap { {"one", 1.2f}, {"two", 2.3f}, {"three", 3.4f} }; json j_umap(c_umap); // {"one": 1.2, "two": 2.3, "three": 3.4} std::multimap c_mmap { {"one", true}, {"two", true}, {"three", false}, {"three", true} }; json j_mmap(c_mmap); // only one entry for key "three" is used // maybe {"one": true, "two": true, "three": true} std::unordered_multimap c_ummap { {"one", true}, {"two", true}, {"three", false}, {"three", true} }; json j_ummap(c_ummap); // only one entry for key "three" is used // maybe {"one": true, "two": true, "three": true} } { // strings std::string s1 = "Hello, world!"; json js = s1; std::string s2 = js; // Booleans bool b1 = true; json jb = b1; bool b2 = jb; // numbers int i = 42; json jn = i; double f = jn; // etc. std::string vs = js.get(); bool vb = jb.get(); int vi = jn.get(); // etc. } { // a JSON value json j_original = R"({ "baz": ["one", "two", "three"], "foo": "bar" })"_json; // access members with a JSON pointer (RFC 6901) j_original["/baz/1"_json_pointer]; // "two" // a JSON patch (RFC 6902) json j_patch = R"([ { "op": "replace", "path": "/baz", "value": "boo" }, { "op": "add", "path": "/hello", "value": ["world"] }, { "op": "remove", "path": "/foo"} ])"_json; // apply the patch json j_result = j_original.patch(j_patch); // { // "baz": "boo", // "hello": ["world"] // } // calculate a JSON patch from two JSON values json::diff(j_result, j_original); // [ // { "op":" replace", "path": "/baz", "value": ["one", "two", "three"] }, // { "op":"remove","path":"/hello" }, // { "op":"add","path":"/foo","value":"bar" } // ] } // restore old std::cout std::cout.rdbuf(old_cout_buffer); } }