Crow syntax for optional query parameters

Question

I'm quite new to C++ and can't get my head around the documentation for Crow Web server.

What I want is to mock an RPC-endpoint, allowing query-parameters to be empty, and if so default them to "". The idea of using .get(value, defaultStr) seems missing or gone..

I'm getting an exception even asking for a parameter that's not there, and no option to set a default value from what i see in the docs.

(tagging with flask since Crow seems to be based upon it)

Here's what i've got:

    CROW_ROUTE(api, "/rpc")
    .methods(crow::HTTPMethod::Get)([&rpcParser](const crow::request &req) {
        // Extract query parameters
        std::string method = req.url_params.get("method");
        std::string key = req.url_params.get("key");
        std::string value = req.url_params.get("value");

        // Check if any of the parameters are missing
        if (method.empty()) {
            return crow::response(400, "Missing required query parameters");
        }
        if (key.empty())
            key = "";
        if (value.empty())
            value = "";

        // Split the method at the first dot
        size_t dot_pos = method.find('.');
        if (dot_pos != std::string::npos) {
            std::string class_name = method.substr(0, dot_pos);   // Extract the part before the dot
            std::string method_name = method.substr(dot_pos + 1); // Extract the part after the dot

            // Call the RPC parser with the split values
            rpcParser.parse(class_name, method_name, key, value);
        } else {
            // Handle the error when there is no dot in the method
            // For example, you might want to send an error response
            return crow::response(400, "Invalid method format");
        }

        // Return a response
        return crow::response(200, "Request processed successfully");
    });

Answer 1

Note to self and others:

.get() returns a char* , not std:string

easy way out (may be prettier ways):

    std::string method = req.url_params.get("method") ? req.url_params.get("method") : "";
    std::string key = req.url_params.get("key") ? req.url_params.get("key") : "";
    std::string value = req.url_params.get("value") ? req.url_params.get("value") : "";