How do I write a minimal GraphQL query of the Axie server? - c++

Question

I'm writing a program to download data about Axies and process them. My plan is to download all the marketplace, getting just the index numbers, then download details about Axies. Before getting all the details about an Axie, I'd like to get just one detail. I've succeeded in making an HTTPS connection to the server and sending a query, but all it replies is "Bad Request".
I've been using Shane Maglangit's site https://axie-graphql.web.app/ for examples, but the examples are too big for me to understand, since I don't know GraphQL or JSON, and part of the queries has literal \n and the other part has linefeeds, which is confusing me. His code is in JavaScript, which I don't know, so I don't know if JS is doing something different with \n than C++ does.
Here's my code:
main.cpp
#include <iostream>
#include <iomanip>
#include <boost/program_options.hpp>
#include "http.h"
using namespace std;
int main(int argc,char **argv)
{
string query="{\n \"operationName\": \"GetAxieDetail\",\n"
" \"variables\":\n {\n \"axieId\": \"5144540\"\n },\n"
" \"query\": \"query GetAxieDetail($axieId: ID!) {\\n ...AxieDetail\\n __typename}\n}"
"fragment AxieDetail on Axie{axie(axieId: $axieId)}\"";
string response;
string urlv2="https://axieinfinity.com/graphql-server-v2/graphql";
string urlv1="https://graphql-gateway.axieinfinity.com/graphql";
response=httpPost(urlv1,query);
cout<<response<<endl;
return 0;
}
http.h
#include <string>
std::string httpPost(std::string url,std::string data);
http.cpp
#include <boost/asio.hpp>
#include <boost/asio/ssl.hpp>
#include <boost/beast.hpp>
#include <boost/beast/ssl.hpp>
#include <boost/asio/ssl/error.hpp>
#include <boost/asio/ssl/stream.hpp>
#include <array>
#include <iostream>
namespace beast=boost::beast;
namespace http=beast::http;
namespace net=boost::asio;
namespace ssl=net::ssl;
using tcp=net::ip::tcp;
using namespace std;
array<string,4> parseUrl(string url)
// protocol, hostname, port, path. All are strings, including the port.
{
size_t pos0=url.find("://");
size_t pos1;
array<string,4> ret;
ret[0]=url.substr(0,pos0);
if (pos0<url.length())
pos0+=3;
pos1=url.find("/",pos0);
ret[1]=url.substr(pos0,pos1-pos0);
ret[3]=url.substr(pos1);
pos0=ret[1].find(":");
if (pos0<ret[1].length())
{
ret[2]=ret[1].substr(pos0+1);
ret[1]=ret[1].substr(0,pos0);
}
else
if (ret[0]=="https")
ret[2]="443";
else if (ret[0]=="https")
ret[2]="80";
else
ret[2]="0";
return ret;
}
string httpPost(string url,string data)
{
net::io_context context;
ssl::context ctx(ssl::context::tlsv12_client);
tcp::resolver res(context);
tcp::resolver::results_type endpoints;
beast::ssl_stream<beast::tcp_stream> stream(context,ctx);
array<string,4> parsed=parseUrl(url);
http::request<http::string_body> req;
http::response<http::string_body> resp;
beast::flat_buffer buffer;
//load_root_certificates(ctx);
ctx.set_verify_mode(ssl::verify_peer);
endpoints=res.resolve(parsed[1],parsed[2]);
beast::get_lowest_layer(stream).connect(endpoints);
SSL_set_tlsext_host_name(stream.native_handle(),parsed[1].c_str());
if (parsed[0]=="https")
stream.handshake(net::ssl::stream_base::client);
req.method(http::verb::post);
req.target(parsed[3]);
req.set(http::field::host,parsed[1]);
req.set(http::field::user_agent,BOOST_BEAST_VERSION_STRING);
req.set(http::field::content_type,"application/json");
req.set(http::field::accept,"application/json");
req.body()=data;
req.prepare_payload();
http::write(stream,req);
http::read(stream,buffer,resp);
cout<<parsed[0]<<"|\n"<<parsed[1]<<"|\n"<<parsed[2]<<"|\n"<<parsed[3]<<"|\n";
cout<<data<<"|\n";
return resp.body();
}
How can I write a query that returns one detail of the Axie with the specified number? Which of the two Axie servers should I use, and what's the difference?

Answer 1

Here is a working query string:
string query="{\n"
" \"operationName\": \"GetAxieDetail\",\n"
" \"variables\":\n"
" {\n"
" \"axieId\": \"5144540\"\n"
" },\n"
" \"query\":\n"
" \"query GetAxieDetail($axieId: ID!)"
" {\\n"
" axie(axieId: $axieId)\\n"
" {\\n"
" class\\n"
" }\\n"
" }\"\n"
"}\n";
The response is:
{"data":{"axie":{"class":"Plant"}}}
The server insists on no line feeds in the quoted query string, but allows \n; the \n, though, makes no difference, as the response is just one line.