#include "crow.h" class ExampleLogHandler : public crow::ILogHandler { public: void log(std::string /*message*/, crow::LogLevel /*level*/) override { // cerr << "ExampleLogHandler -> " << message; } }; struct ExampleMiddleware { std::string message; ExampleMiddleware(): message("foo") { } void setMessage(const std::string& newMsg) { message = newMsg; } struct context {}; void before_handle(crow::request& /*req*/, crow::response& /*res*/, context& /*ctx*/) { CROW_LOG_DEBUG << " - MESSAGE: " << message; } void after_handle(crow::request& /*req*/, crow::response& /*res*/, context& /*ctx*/) { // no-op } }; int main() { crow::App app; app.get_middleware().setMessage("hello"); CROW_ROUTE(app, "/") .name("hello")([] { return "Hello World!"; }); CROW_ROUTE(app, "/about") ([]() { return "About Crow example."; }); // a request to /path should be forwarded to /path/ CROW_ROUTE(app, "/path/") ([]() { return "Trailing slash test case.."; }); // simple json response CROW_ROUTE(app, "/json") ([] { crow::json::wvalue x({{"message", "Hello, World!"}}); x["message2"] = "Hello, World.. Again!"; return x; }); CROW_ROUTE(app, "/json-initializer-list-constructor") ([] { return crow::json::wvalue({ {"first", "Hello world!"}, /* stores a char const* hence a json::type::String */ {"second", std::string("How are you today?")}, /* stores a std::string hence a json::type::String. */ {"third", std::int64_t(54)}, /* stores a 64-bit int hence a std::int64_t. */ {"fourth", std::uint64_t(54)}, /* stores a 64-bit unsigned int hence a std::uint64_t. */ {"fifth", 54}, /* stores an int (as 54 is an int literal) hence a std::int64_t. */ {"sixth", 54u}, /* stores an unsigned int (as 54u is a unsigned int literal) hence a std::uint64_t. */ {"seventh", 2.f}, /* stores a float (as 2.f is a float literal) hence a double. */ {"eighth", 2.}, /* stores a double (as 2. is a double literal) hence a double. */ {"ninth", nullptr}, /* stores a std::nullptr hence json::type::Null . */ {"tenth", true} /* stores a bool hence json::type::True . */ }); }); // json list response CROW_ROUTE(app, "/json_list") ([] { crow::json::wvalue x(crow::json::wvalue::list({1, 2, 3})); return x; }); // To see it in action enter {ip}:18080/hello/{integer_between -2^32 and 100} and you should receive // {integer_between -2^31 and 100} bottles of beer! CROW_ROUTE(app, "/hello/") ([](int count) { if (count > 100) return crow::response(400); std::ostringstream os; os << count << " bottles of beer!"; return crow::response(os.str()); }); // Same as above, but using crow::status CROW_ROUTE(app, "/hello_status/") ([](int count) { if (count > 100) return crow::response(crow::status::BAD_REQUEST); std::ostringstream os; os << count << " bottles of beer!"; return crow::response(os.str()); }); // To see it in action submit {ip}:18080/add/1/2 and you should receive 3 (exciting, isn't it) CROW_ROUTE(app, "/add//") ([](crow::response& res, int a, int b) { std::ostringstream os; os << a + b; res.write(os.str()); res.end(); }); //same as the example above but uses mustache instead of stringstream CROW_ROUTE(app, "/add_mustache//") ([](int a, int b) { auto t = crow::mustache::compile("Value is {{func}}"); crow::mustache::context ctx; ctx["func"] = [&](std::string) { return std::to_string(a + b); }; auto result = t.render(ctx); return result; }); // Compile error with message "Handler type is mismatched with URL paramters" //CROW_ROUTE(app,"/another/") //([](int a, int b){ //return crow::response(500); //}); // more json example // To see it in action, I recommend to use the Postman Chrome extension: // * Set the address to {ip}:18080/add_json // * Set the method to post // * Select 'raw' and then JSON // * Add {"a": 1, "b": 1} // * Send and you should receive 2 // A simpler way for json example: // * curl -d '{"a":1,"b":2}' {ip}:18080/add_json CROW_ROUTE(app, "/add_json") .methods("POST"_method)([](const crow::request& req) { auto x = crow::json::load(req.body); if (!x) return crow::response(400); int sum = x["a"].i() + x["b"].i(); std::ostringstream os; os << sum; return crow::response{os.str()}; }); // Example of a request taking URL parameters // If you want to activate all the functions just query // {ip}:18080/params?foo='blabla'&pew=32&count[]=a&count[]=b CROW_ROUTE(app, "/params") ([](const crow::request& req) { std::ostringstream os; // To get a simple string from the url params // To see it in action /params?foo='blabla' os << "Params: " << req.url_params << "\n\n"; os << "The key 'foo' was " << (req.url_params.get("foo") == nullptr ? "not " : "") << "found.\n"; // To get a double from the request // To see in action submit something like '/params?pew=42' if (req.url_params.get("pew") != nullptr) { double countD = crow::utility::lexical_cast(req.url_params.get("pew")); os << "The value of 'pew' is " << countD << '\n'; } // To get a list from the request // You have to submit something like '/params?count[]=a&count[]=b' to have a list with two values (a and b) auto count = req.url_params.get_list("count"); os << "The key 'count' contains " << count.size() << " value(s).\n"; for (const auto& countVal : count) { os << " - " << countVal << '\n'; } // To get a dictionary from the request // You have to submit something like '/params?mydict[a]=b&mydict[abcd]=42' to have a list of pairs ((a, b) and (abcd, 42)) auto mydict = req.url_params.get_dict("mydict"); os << "The key 'dict' contains " << mydict.size() << " value(s).\n"; for (const auto& mydictVal : mydict) { os << " - " << mydictVal.first << " -> " << mydictVal.second << '\n'; } return crow::response{os.str()}; }); CROW_ROUTE(app, "/large") ([] { return std::string(512 * 1024, ' '); }); // Take a multipart/form-data request and print out its body CROW_ROUTE(app, "/multipart") ([](const crow::request& req) { crow::multipart::message msg(req); CROW_LOG_INFO << "body of the first part " << msg.parts[0].body; return "it works!"; }); // enables all log app.loglevel(crow::LogLevel::Debug); //crow::logger::setHandler(std::make_shared()); app.port(18080) .multithreaded() .run(); }