cpprestsdk: handle chunked response - c++

Question

How should I handle chunked response using cpprestsdk? How to request the next chunk? Is there required functionality at all there?
Here is how we are performing http requests:
web::http::http_request request(web::http::methods::GET);
request.headers().add(LR"(User-Agent)", LR"(ExchangeServicesClient/15.00.0847.030)");
request.headers().add(LR"(Accept)", LR"(text/xml)");
request.set_body(L"request body", L"text/xml");
web::http::client::http_client_config clientConfig;
clientConfig.set_credentials(web::credentials(L"username", L"pass"));
clientConfig.set_validate_certificates(true);
web::http::client::http_client client(L"serviceurl", clientConfig);
auto bodyTask = client.request(request)
.then([](web::http::http_response response) {
auto str = response.extract_string().get();
return str;
});
auto body = bodyTask.get();
If I'm trying naively to perform another request just after this one then I got an error:
WinHttpSendRequest: 5023: The group or resource is not in the correct state to perform the
requested operation.

Answer 1

In order to read received data in chunks, one needs to get the input stream from the server response
concurrency::streams::istream bodyStream = response.body();
then read continuously from that stream until a given char is found or the number of specified bytes is read
pplx::task<void> repeat(Concurrency::streams::istream bodyStream)
{
Concurrency::streams::container_buffer<std::string> buffer;
return pplx::create_task([=] {
auto t = bodyStream.read_to_delim(buffer, '\n').get();
std::cout << buffer.collection() << std::endl;
return t;
}).then([=](int /*bytesRead*/) {
if (bodyStream.is_eof()) {
return pplx::create_task([]{});
}
return repeat(bodyStream);
});
}
Here is the full sample: https://github.com/cristeab/oanda_stream