Http_client post request using C++ REST SDK (Casablanca)

Question

I'm trying to perform a POST HTTP request using C++ REST SDK (Casablanca) library, but I'm not succeeding... Nor I can find any recent/working snippet. Can anybody help me?

With my following code I obtain a runtime web::json::json_exception saying "not a string":

json::value postData;
postData[L"name"] = json::value::string(L"Joe Smith");
postData[L"sport"] = json::value::string(L"Baseball");

web::http::client::http_client client(L"https://jsonplaceholder.typicode.com/posts");

try
{
    client.request(
        methods::POST,
        L"",
        postData/*.as_string().c_str()*/,
        L"application/json");
}
catch (web::json::json_exception &je)
{
    std::cout << je.what();
}
catch (std::exception &e)
{
    std::cout << e.what();
}

If you make your minimal code cut N paste runnable it will help us help you — Scott Stensland, Feb 21 '17 at 14:40
Have you tried removing the last parameter of client.request() (L"application/json") ? — roalz, Feb 21 '17 at 14:45
Hmm, try replace whenever you have `L"somestring"` with `U("somestring")` — Yuriy Ivaskevych, Feb 21 '17 at 14:47

score 8 · Answer 1 · edited May 11 '22 at 15:11

Something like that will do for you:

        web::json::value json_return;
        web::json::value json_v ;
        json_v["title"] = web::json::value::string("foo");
        json_v["body"] = web::json::value::string("bar");
        json_v["userId"] = web::json::value::number(1);
        web::http::client::http_client client("https://jsonplaceholder.typicode.com/posts");
        client.request(web::http::methods::POST, U("/"), json_v)
        .then([](const web::http::http_response& response) {
            return response.extract_json(); 
        })
        .then([&json_return](const pplx::task<web::json::value>& task) {
            try {
                json_return = task.get();
            }
            catch (const web::http::http_exception& e) {                    
                std::cout << "error " << e.what() << std::endl;
            }
        })
        .wait();
        
        std::cout << json_return.serialize() << std::endl;

You can also simply parse the string like that:

        web::json::value json_par;
        json_par.parse("{\"title\": \"foo\", \"body\": \"bar\", \"userId\": 1}");

Just after use the json object the same way than in the first example. It is slightly easier if you read the json from a file.

how is `json_return` declared? I am getting an undeclared error. — Ganesh Kamath - 'Code Frenzy', Nov 08 '19 at 08:01
I have come to this post after 3 years and found my commen unanswered, I have updated the declaration of `json_return` after testing it on my current solution. — Ganesh Kamath - 'Code Frenzy', May 11 '22 at 15:12

Http_client post request using C++ REST SDK (Casablanca)

1 Answers1