Integrate POST HTTP request with multi-curl manager

[dentiny]

duckdb-curl-filesystem/src/httpfs_curl_client.cpp

Lines 295 to 331 in a27dd4a

	unique_ptr<HTTPResponse> Post(PostRequestInfo &info) override {
	if (state) {
	state->post_count++;
	state->total_bytes_sent += info.buffer_in_len;
	}
	auto curl_headers = TransformHeadersCurl(info.headers);
	const string content_type = "Content-Type: application/octet-stream";
	curl_headers.Add(content_type.c_str());
	// transform parameters
	request_info->url = info.url;
	if (!info.params.extra_headers.empty()) {
	auto curl_params = TransformParamsCurl(info.params);
	request_info->url += "?" + curl_params;
	}
	CURLcode res;
	{
	curl_easy_setopt(*curl, CURLOPT_URL, request_info->url.c_str());
	curl_easy_setopt(*curl, CURLOPT_POST, 1L);
	// Set POST body
	curl_easy_setopt(*curl, CURLOPT_POSTFIELDS, const_char_ptr_cast(info.buffer_in));
	curl_easy_setopt(*curl, CURLOPT_POSTFIELDSIZE, info.buffer_in_len);
	// Add headers if any
	curl_easy_setopt(*curl, CURLOPT_HTTPHEADER, curl_headers ? curl_headers.headers : nullptr);
	// Execute POST request
	res = curl->Execute();
	}
	curl_easy_getinfo(*curl, CURLINFO_RESPONSE_CODE, &request_info->response_code);
	info.buffer_out = request_info->body;
	// Construct HTTPResponse
	return TransformResponseCurl(res);
	}