[Question]: query url param

[Milerius]

Hello i'm looking the sample,

I try to retrieve params from a getter url: /api/restcall?option1=value&option2=value

How to retrieve option1 and option2 in the code ?

[Milerius]

I think i should use const auto qp = restinio::parse_query( req->header().query() );

But i was thinking it"s was for optional header, not query

[eao197]

Step 1. Use parse_query to split query string to key-value pais:

const auto qp = restinio::parse_query( req->header().query() );

Step 2. Use methods of restinio::query_string_params_t to check the presence of a key. See https://stiffstream.com/en/docs/restinio/0.5/querystringparams.html and https://stiffstream.com/en/docs/restinio/0.5/valueor.html for more details and example.

[Milerius]

Yeah i'm on it, by the way, the library is incredibly well coded in modern C++ with a very nice use of modern and clear feature.

[Milerius]

@eao197 How we convert the string_view result into a std::string ?

.data() is undefined behavior according to the standard. (no \0)

restinio::request_handling_status_t
    price::get_price(restinio::request_handle_t req, restinio::router::route_params_t)
    {
        VLOG_SCOPE_F(loguru::Verbosity_INFO, pretty_function);
        DVLOG_F(loguru::Verbosity_INFO, "http call: %s", "/api/v1/getprice");
        const auto qp = restinio::parse_query(req->header().query());
        if (qp.size() != 2) {
            DVLOG_F(loguru::Verbosity_ERROR, "Not enough parameters, require base_currency and quote_currency parameters");
            return req->create_response(restinio::status_bad_request()).done();
        }
        if (!qp.has("base_currency") || !qp.has("quote_currency")) {
            DVLOG_F(loguru::Verbosity_ERROR, "Wrong parameters, require base_asset and quote_asset parameters");
            return req->create_response(restinio::status_unprocessable_entity()).done();
        }
        std::string res = qp["base_currency"]; //! not compiling i need it as string for filling my structure antara::pair
        antara::pair currency_pair{asset{st_symbol{}}, asset{st_symbol{}}};
        return req->create_response(restinio::status_ok()).set_body("Done").done();
    }

std::string(qp["base_currency"]); ???

[eao197]

What's about:

std::string res = restinio::cast_to<std::string>(qp["base_currency"]);

?

[Milerius]

std::string(qp["base_currency"]); this compile and seem's to work, do you suggest i use cast_to ?

[eao197]

std::string(qp["base_currency"]);

It depends on your C++ version. In C++17 and in new compilers std::string has a constructor that accepts string_view (and in that case restinio::string_view_t is just a synonym for std::string_view). If you use C++14 and rather old compiler cast_to is the solution.

[Milerius]

I'm using c++17, i will then use the constructor thank's a lot !