Boost.Beast: Is it possible to construct an HTTP batch request? - c++

Question

I've been using Boost.Beast for awhile now to send HTTP requests and I think it's great and works perfectly. But does anyone know if it's possible to construct an HTTP batch request using Beast? I'm thinking something like creating several subrequests:
boost::beast::http::request<boost::beast::http::string_body> subrequest_1;
subrequest_1.set(boost::beast::http::field::content_type, "application/http");
...
boost::beast::http::request<boost::beast::http::string_body> subrequest_2;
subrequest_2.set(boost::beast::http::field::content_type, "application/http");
...
and then somehow group them together and send them all in one request.
I've been trying to create a vector, add the subrequests to it and then assign the vector to the body of the request I'd like to send, but that hasn't been successful.
/*
std::vector<boost::beast::http::request<boost::beast::http::string_body>> v;
v.push_back(subrequest_1);
v.push_back(subrequest_2);
boost::beast::http::request<boost::beast::http::string_body> request;
request.method(boost::beast::http::verb::post);
...
request.body() = v;
*/
Thanks in advance!

Answer 1

Well this one turned out to be very simple. I'll just post my solution here in case anyone else feels as lost as I did a couple of days ago.
// Set up the request with a new content type
boost::beast::http::request<boost::beast::http::string_body> request;
request.set(field::content_type, "multipart/mixed; boundary='subrequest_boundary'");
// A string to hold the entire batch request
std::string body;
// Add all messages in e.g. a queue to the string
while ( messages.size() )
{
auto message = messages.front();
// Add a boundary to separate the messages
body.append("--subrequest_boundary");
body.append("Content-Type: application/http\n");
/*
And all more headers you need
*/
// I used the nlohmann library to add json docs
nlohmann::json payload = {
{"message",
}
};
body.append( payload.dump() );
messages.pop();
}
// Add a boundary as wrap up
body.append("--subrequest_boundary--");
// Add the batch request to the request
request.body() = body;
request.prepare_payload();