Questions about v3.6.0

[wravery]

Thank you @wravery . after changing that modification in my make file. I am getting the output without the error of the HelloClient program. Please check my question also in stackoverflow. In your samples of cppgraphiql doesn't run with dependency of electron-cppgraphql. Other than that. In my project we were using Napi.h. How to rewrite your samples for TodayMock with Napi.h. I am creating HelloMock like TodayMock from samples code placed in project directory. I commented Napi.h codings in "hello.cpp". But in this time i got the following errors

makefile

CFLAGS = -Os -O3 -fPIC -Ofast -std=gnu++17

CC = gcc
CXX = g++

LDFLAGS := \
	-pthread \
	-rdynamic

DEFS := \
	'-DUSING_UV_SHARED=1' \
	'-DUSING_V8_SHARED=1' \
	'-DV8_DEPRECATION_WARNINGS=1' \
	'-DV8_DEPRECATION_WARNINGS' \
	'-DV8_IMMINENT_DEPRECATION_WARNINGS' \
	'-D_LARGEFILE_SOURCE' \
	'-D_FILE_OFFSET_BITS=64' \
	'-DOPENSSL_NO_PINSHARED' \
	'-DOPENSSL_THREADS'	\
	'-D__STDC_FORMAT_MACROS' \
	'-DNAPI_DISABLE_CPP_EXCEPTIONS' \
	'-DBUILDING_NODE_EXTENSION'

# Flags passed to all source files.
GYP_CFLAGS := \
	-frtti \
	-fexceptions \
	-pthread \
	-Wall \
	-Wextra \
	-Wno-unused-parameter \
	-fno-omit-frame-pointer

# Flags passed to only C files.
CFLAGS_C :=

# Flags passed to only C++ files.
CFLAGS_CC := \
	-std=gnu++1y \
	-fexceptions

INC_NAPI := -I/usr/include/node-addon-api
INC_NODE := -I/usr/include/node
# INC := -I./separate
# INC := -I./separate -I../cppgraphqlgen/include -I../cppgraphqlgen/PEGTL/include

# INC_NAPI = -I/usr/lib/node_modules/node-addon-api
# INC_NODE := -I/usr/include/node

CGI_LIB = -lcgicc

# LIBS := /home/jeya/cpp-graphql-projects/cppgraphqlgen/src
LIBS := /usr/local/lib
GRPHQL := -L${LIBS}/libgraphqlclient.a -L${LIBS}/libgraphqljson.a  -L${LIBS}/libgraphqlintrospection.a  -L${LIBS}/libgraphqlservice.a  -L${LIBS}/libgraphqlresponse.a  -L${LIBS}/libgraphqlpeg.a
NOTH_A = nothing.a

# OBJ = nothing.o ./today/sampleQryParse.o ./hello/HelloClient.o ./hello/hello.o

# ENODE = ${NOTH_A} ./today/sampleQryParse.node ./hello/HelloClient.node ./hello/hello.o

OBJ = nothing.o ./hello/HelloClient.o

ENODE = nothing.a ./hello/HelloClient.node ./hello/hello

# GREET_DEMO = ./greet-demo
# CLASS_DEMO = ./class-demo
DEMO := ./today
HELLO := ./hello
target: ${OBJ} ${ENODE}

clean:
	rm -rf *.o *.node *.a
	rm -rf ${DEMO}/*.o ${DEMO}/*.node
	rm -rf ${HELLO}/*.o ${HELLO}/*.node

./today/sampleQryParse.o: ./today/sampleQryParse.cpp
	${CXX} ${CFLAGS} -shared '-DNODE_GYP_MODULE_NAME=sampleQryParse' ${GYP_CFLAGS} ${INC_NODE} ${INC_NAPI} -c $< -o $@

./today/sampleQryParse.node: ./today/sampleQryParse.o
	${CXX} -shared -Wl,-soname=sampleQryParse.node -Wl,--start-group ./today/sampleQryParse.o ${NOTH_A} ${GRPHQL} -Wl,--end-group -o $@

./hello/hello.o: ./hello/hello.cpp
	${CXX} ${CFLAGS} '-DNODE_GYP_MODULE_NAME=hello' ${DEFS} ${GYP_CFLAGS} ${INC_NAPI} ${INC_NODE} -c $< -o $@

./hello/hello.node: ./hello/hello.o
	${CXX} ${CFLAGS} ./hello/hello.o -shared -Wl,-soname=hello.node -Wl,--start-group -lpthread ${GRPHQL} ${NOTH_A} -Wl,--end-group -o $@

./hello/hello: ./hello/hello.cpp
	${CXX} ${CFLAGS} ./hello/hello.cpp -shared -Wl,-soname=hello -Wl,--start-group -lpthread ${GRPHQL} -Wl,--end-group -o $@

# ./hello/HelloClient: ./hello/HelloClient.cpp
# 	${CXX} ${CFLAGS} $< -o $@

./hello/HelloClient.o: ./hello/HelloClient.cpp
	${CXX} ${CFLAGS} '-DNODE_GYP_MODULE_NAME=HelloClient' ${DEFS} ${GYP_CFLAGS} ${INC_NAPI} ${INC_NODE} -c $< -o $@

./hello/HelloClient.node: ./hello/HelloClient.o
	${CXX} ${CFLAGS} -shared -Wl,-soname=HelloClient.node -Wl,--start-group ./hello/HelloClient.o ${GRPHQL} -lpthread ${NOTH_A} -Wl,--end-group -o $@

./today/sampleOne.o: ./today/sample.cpp
	${CXX} ${CFLAGS} -c $< -o $@

./today/sampleOne:
	${CXX} ${CFLAGS} ./today/sample.cpp -shared -Wl,-soname=sampleOne.node -Wl,--start-group ${GRPHQL} -lpthread ${NOTH_A} -Wl,--end-group -o $@

nothing.a: nothing.o
	ar crs nothing.a $<

nothing.o: nothing.c
	${CC} ${LDFLAGS} ${INC_NODE} ${DEFS} -c $< -o $@ 

HelloMock.h

#pragma once

#ifndef HELLOMOCK_H
#define HELLOMOCK_H

#include "HelloSchema.h"

#include <atomic>
#include <stack>

namespace graphql::hello
{
    class Hello;

    class Query
    {
        using helloLoader = std::function<std::vector<std::shared_ptr<Hello>>()>;
        public:
            explicit Query(helloLoader &&getHelloMsg);
            virtual service::FieldResult<std::optional<response::StringType>> getHelloMsg(service::FieldParams &&params) const final;
        private:
            // Lazy load the fields in each query
            void loadMsg(const std::shared_ptr<service::RequestState> &state) const;
            mutable helloLoader _getHelloMsg;
            mutable std::vector<std::shared_ptr<Hello>> _hello;
    };

    class Hello
    {
        public:
            explicit Hello(std::string&& greet);
            virtual service::FieldResult<std::optional<response::StringType>> getGreetMsg() final;
            virtual service::FieldResult<std::optional<response::StringType>> getForceError(
                service::FieldParams &&) const final
            {
                throw std::runtime_error(R"ex(this error was forced)ex");
            }

        private:
            std::string _greet;

        
    };

}

#endif // HELLOMOCK_H

HelloMock.cpp

#include "HelloMock.h"

#include <algorithm>
#include <iostream>

namespace graphql::hello
{

    Hello::Hello(std::string&& greet) : _greet(greet)
    {
    }
    service::FieldResult<std::optional<response::StringType>> Hello::getGreetMsg()
    {
        return _greet;
    }

    Query::Query(helloLoader&& getHelloMsg)
    {
    }
    void Query::loadMsg(const std::shared_ptr<service::RequestState> &state) const
    {
        if (_getHelloMsg)
        {
            _hello = _getHelloMsg();
            _getHelloMsg = nullptr;
        }
    }

    // std::shared_ptr<Hello> Query::findHelloMsg(
    //     const service::FieldParams &params, const response::IdType &id) const
    // {
    //     loadMsg(params.state);

    //     for (const auto &hello : _hello)
    //     {
    //         if (hello->id() == id)
    //         {
    //             return appointment;
    //         }
    //     }

    //     return nullptr;
    // }

} // namespace graphql::hello

hello.cpp

// #include <napi.h>
#include "HelloMock.h"

#include "graphqlservice/JSONResponse.h"
#include <cstdio>
#include <iostream>
#include <iterator>
#include <stdexcept>

using namespace graphql;

// Napi::String parseQuery(const Napi::CallbackInfo &info)
int main(int argc, char **argv)
{
    // Napi::Env env = info.Env();
    /* From HelloMock*/
    response::StringType helloKey;

    std::string fakeHelloKey("hello");
    helloKey.resize(fakeHelloKey.size());
    std::copy(fakeHelloKey.cbegin(), fakeHelloKey.cend(), helloKey.begin());
    
    std::cout << "Created the service..." << std::endl;

    auto query = std::make_shared<hello::Query>(
        [&fakeHelloKey]() -> std::vector<std::shared_ptr<hello::Hello>>
        {
            std::cout << "Called getHelloMsg..." << std::endl;
            return {std::make_shared<hello::Hello>("Hello World!")};
        }
    );
        
    auto service = std::make_shared<hello::Operations>(query);
    std::cout << "Created the service..." << std::endl;

    try
    {
        peg::ast query;
        // std::string qry = info[0].As<std::string>();
        // query = peg::parseString(std::move(qry));
        if (argc > 1)
        {
            query = peg::parseFile(argv[1]);
        }
        else
        {
            std::istream_iterator<char> start{std::cin >> std::noskipws}, end{};
            std::string input{start, end};

            query = peg::parseString(std::move(input));
        }
        if (!query.root)
        {
            std::cerr << "Unknown error!" << std::endl;
            std::cerr << std::endl;
            // return Napi::String::New(env, "1");
            return 1;
        }

        std::cout << "Executing query..." << std::endl;

        // std::stringstream out;
        // out << response::toJSON(service
        //                             ->resolve(nullptr,
        //                                       query,
        //                                       "",
        //                                       response::Value(response::Type::Map))
        //                             .get());
        // std::string res = out.str();
        // return Napi::String::New(env, res);
        std::cout << response::toJSON(service
                                          ->resolve(nullptr,
                                                    query,
                                                    ((argc > 2) ? argv[2] : ""),
                                                    response::Value(response::Type::Map))
                                          .get())
                  << std::endl;
    }
    catch (const std::runtime_error &ex)
    {
        std::cerr << ex.what() << std::endl;
        // return Napi::String::New(env, "1");
        return 1;
    }

    // return Napi::String::New(env, "0");
    return 0;
}

// Napi::Object Init(Napi::Env env, Napi::Object exports)
// {
//     exports.Set("parseQuery", Napi::Function::New(env, parseQuery));
//     return exports;
// }

// NODE_API_MODULE(NODE_GYP_MODULE_NAME, Init);

Error:

ar crs nothing.a nothing.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -shared -Wl,-soname=HelloClient.node -Wl,--start-group ./hello/HelloClient.o -L/usr/local/lib/libgraphqlclient.a -L/usr/local/lib/libgraphqljson.a  -L/usr/local/lib/libgraphqlintrospection.a  -L/usr/local/lib/libgraphqlservice.a  -L/usr/local/lib/libgraphqlresponse.a  -L/usr/local/lib/libgraphqlpeg.a -lpthread nothing.a -Wl,--end-group -o hello/HelloClient.node
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 ./hello/hello.cpp -shared -Wl,-soname=hello -Wl,--start-group -lpthread -L/usr/local/lib/libgraphqlclient.a -L/usr/local/lib/libgraphqljson.a  -L/usr/local/lib/libgraphqlintrospection.a  -L/usr/local/lib/libgraphqlservice.a  -L/usr/local/lib/libgraphqlresponse.a  -L/usr/local/lib/libgraphqlpeg.a -Wl,--end-group -o hello/hello
In file included from /usr/include/x86_64-linux-gnu/c++/10/bits/c++allocator.h:33,
                 from /usr/include/c++/10/bits/allocator.h:46,
                 from /usr/include/c++/10/memory:64,
                 from /usr/local/include/graphqlservice/GraphQLParse.h:21,
                 from /usr/local/include/graphqlservice/GraphQLService.h:21,
                 from /usr/local/include/graphqlservice/internal/Schema.h:9,
                 from ./hello/HelloSchema.h:11,
                 from ./hello/HelloMock.h:6,
                 from ./hello/hello.cpp:2:
/usr/include/c++/10/ext/new_allocator.h: In instantiation of ‘void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = graphql::hello::Operations; _Args = {std::shared_ptr<graphql::hello::Query>&}; _Tp = graphql::hello::Operations]’:
/usr/include/c++/10/bits/alloc_traits.h:512:17:   required from ‘static void std::allocator_traits<std::allocator<_Tp1> >::construct(std::allocator_traits<std::allocator<_Tp1> >::allocator_type&, _Up*, _Args&& ...) [with _Up = graphql::hello::Operations; _Args = {std::shared_ptr<graphql::hello::Query>&}; _Tp = graphql::hello::Operations; std::allocator_traits<std::allocator<_Tp1> >::allocator_type = std::allocator<graphql::hello::Operations>]’
/usr/include/c++/10/bits/shared_ptr_base.h:551:39:   required from ‘std::_Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp>::_Sp_counted_ptr_inplace(_Alloc, _Args&& ...) [with _Args = {std::shared_ptr<graphql::hello::Query>&}; _Tp = graphql::hello::Operations; _Alloc = std::allocator<graphql::hello::Operations>; __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]’
/usr/include/c++/10/bits/shared_ptr_base.h:682:16:   required from ‘std::__shared_count<_Lp>::__shared_count(_Tp*&, std::_Sp_alloc_shared_tag<_Alloc>, _Args&& ...) [with _Tp = graphql::hello::Operations; _Alloc = std::allocator<graphql::hello::Operations>; _Args = {std::shared_ptr<graphql::hello::Query>&}; __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]’
/usr/include/c++/10/bits/shared_ptr_base.h:1371:71:   required from ‘std::__shared_ptr<_Tp, _Lp>::__shared_ptr(std::_Sp_alloc_shared_tag<_Tp>, _Args&& ...) [with _Alloc = std::allocator<graphql::hello::Operations>; _Args = {std::shared_ptr<graphql::hello::Query>&}; _Tp = graphql::hello::Operations; __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]’
/usr/include/c++/10/bits/shared_ptr.h:408:59:   required from ‘std::shared_ptr<_Tp>::shared_ptr(std::_Sp_alloc_shared_tag<_Tp>, _Args&& ...) [with _Alloc = std::allocator<graphql::hello::Operations>; _Args = {std::shared_ptr<graphql::hello::Query>&}; _Tp = graphql::hello::Operations]’
/usr/include/c++/10/bits/shared_ptr.h:859:14:   required from ‘std::shared_ptr<_Tp> std::allocate_shared(const _Alloc&, _Args&& ...) [with _Tp = graphql::hello::Operations; _Alloc = std::allocator<graphql::hello::Operations>; _Args = {std::shared_ptr<graphql::hello::Query>&}]’
/usr/include/c++/10/bits/shared_ptr.h:875:39:   required from ‘std::shared_ptr<_Tp> std::make_shared(_Args&& ...) [with _Tp = graphql::hello::Operations; _Args = {std::shared_ptr<graphql::hello::Query>&}]’
./hello/hello.cpp:33:61:   required from here
/usr/include/c++/10/ext/new_allocator.h:150:4: error: no matching function for call to ‘graphql::hello::Operations::Operations(std::shared_ptr<graphql::hello::Query>&)’
  150 |  { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
      |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ./hello/HelloMock.h:6,
                 from ./hello/hello.cpp:2:
./hello/HelloSchema.h:52:11: note: candidate: ‘graphql::hello::Operations::Operations(std::shared_ptr<graphql::hello::object::Query>)’
   52 |  explicit Operations(std::shared_ptr<object::Query> query);
      |           ^~~~~~~~~~
./hello/HelloSchema.h:52:53: note:   no known conversion for argument 1 from ‘shared_ptr<graphql::hello::Query>’ to ‘shared_ptr<graphql::hello::object::Query>’
   52 |  explicit Operations(std::shared_ptr<object::Query> query);
      |                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
make: *** [makefile:89: hello/hello] Error 1

Using Schema

schema.hello.graphql

type Query {
    hello: String
}

query.hello.graphql

# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License.

query {
    hello
}

Excpected output

{"data":{"hello":"Hello World!"}}

How to resolve that error message and how to get the final expected output?

Originally posted by @YJPrakash in #172 (comment)

[wravery]

I think the next error is because class Query does not inherit from object::Query, which is required in v3.x.

You also need to override and match the signature of the virtual field accessors from object::Query in your implementation, but it looks like you've done that already.

[YJPrakash]

After inheriting of class Query from object::Query is compiled without errors. Thank you @wravery.

Then I am enabling Napi.h following errors occur. If there any LDflags want to add for graphql::service.

following libraries added for making hello.node -L/usr/local/lib/libgraphqlclient.a -L/usr/local/lib/libgraphqljson.a -L/usr/local/lib/libgraphqlintrospection.a -L/usr/local/lib/libgraphqlservice.a -L/usr/local/lib/libgraphqlresponse.a -L/usr/local/lib/libgraphqlpeg.a . Please take a look at it.

hello.cpp

#include <napi.h>
#include "HelloMock.h"

#include "graphqlservice/JSONResponse.h"
#include <cstdio>
#include <iostream>
#include <iterator>
#include <stdexcept>

using namespace graphql;

Napi::String parseQuery(const Napi::CallbackInfo &info)
// int main(int argc, char **argv)
{
    std::cout << "start hello 1" << std::endl;
    Napi::Env env = info.Env();
    /* From HelloMock*/
    response::StringType helloKey;

    std::string fakeHelloKey("hello");
    helloKey.resize(fakeHelloKey.size());
    std::copy(fakeHelloKey.cbegin(), fakeHelloKey.cend(), helloKey.begin());
    
    std::cout << "Created the service..." << std::endl;

    auto query = std::make_shared<hello::Query>(
        [&fakeHelloKey]() -> std::vector<std::shared_ptr<hello::Hello>>
        {
            std::cout << "Called getHelloMsg..." << std::endl;
            return {std::make_shared<hello::Hello>("Hello World!")};
        }
    );
        
    auto service = std::make_shared<hello::Operations>(query);
    std::cout << "Created the service..." << std::endl;

    try
    {
        peg::ast query;
        // std::string qry = info[0].As<std::string>();
        // query = peg::parseString(std::move(qry));
        // if (argc > 1)
        // {
        //     query = peg::parseFile(argv[1]);
        // }
        // else
        // {
            std::istream_iterator<char> start{std::cin >> std::noskipws}, end{};
            std::string input{start, end};

            query = peg::parseString(std::move(input));
        // }
        if (!query.root)
        {
            std::cerr << "Unknown error!" << std::endl;
            std::cerr << std::endl;
            return Napi::String::New(env, "1");
            // return 1;
        }

        std::cout << "Executing query..." << std::endl;

        std::stringstream out;
        out << response::toJSON(service
                                    ->resolve(nullptr,
                                              query,
                                              "",
                                              response::Value(response::Type::Map))
                                    .get());
        std::string res = out.str();
        return Napi::String::New(env, res);
        // std::cout << response::toJSON(service
        //                                   ->resolve(nullptr,
        //                                             query,
        //                                             ((argc > 2) ? argv[2] : ""),
        //                                             response::Value(response::Type::Map))
        //                                   .get())
        //           << std::endl;
    }
    catch (const std::runtime_error &ex)
    {
        std::cerr << ex.what() << std::endl;
        return Napi::String::New(env, "1");
        // return 1;
    }

    return Napi::String::New(env, "0");
    // return 0;
}

Napi::Object Init(Napi::Env env, Napi::Object exports)
{
    exports.Set("parseQuery", Napi::Function::New(env, parseQuery));
    return exports;
}

NODE_API_MODULE(NODE_GYP_MODULE_NAME, Init);

Error:

i) For commented line conversion is not working when enabling // std::string qry = info[0].As<std::string>(); error like typedef std::__cxx11::basic_string.
ii) Node addon program compiled successfully after commented above line. after calling parseQuery function from nodejs error like Error: ./hello/hello.node: undefined symbol: _ZTIN7graphql7service6ObjectE

Detailed error log:

$ make 
gcc -pthread -rdynamic -I/usr/include/node '-DUSING_UV_SHARED=1' '-DUSING_V8_SHARED=1' '-DV8_DEPRECATION_WARNINGS=1' '-DV8_DEPRECATION_WARNINGS' '-DV8_IMMINENT_DEPRECATION_WARNINGS' '-D_LARGEFILE_SOURCE' '-D_FILE_OFFSET_BITS=64' '-DOPENSSL_NO_PINSHARED' '-DOPENSSL_THREADS' '-D__STDC_FORMAT_MACROS' '-DNAPI_DISABLE_CPP_EXCEPTIONS' '-DBUILDING_NODE_EXTENSION' -c nothing.c -o nothing.o 
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 '-DUSING_UV_SHARED=1' '-DUSING_V8_SHARED=1' '-DV8_DEPRECATION_WARNINGS=1' '-DV8_DEPRECATION_WARNINGS' '-DV8_IMMINENT_DEPRECATION_WARNINGS' '-D_LARGEFILE_SOURCE' '-D_FILE_OFFSET_BITS=64' '-DOPENSSL_NO_PINSHARED' '-DOPENSSL_THREADS' '-D__STDC_FORMAT_MACROS' '-DNAPI_DISABLE_CPP_EXCEPTIONS' '-DBUILDING_NODE_EXTENSION' -frtti -fexceptions -pthread -Wall -Wextra -Wno-unused-parameter -fno-omit-frame-pointer -I/usr/include/node-addon-api -I/usr/include/node -c hello/HelloSchema.cpp -o hello/HelloSchema.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 '-DUSING_UV_SHARED=1' '-DUSING_V8_SHARED=1' '-DV8_DEPRECATION_WARNINGS=1' '-DV8_DEPRECATION_WARNINGS' '-DV8_IMMINENT_DEPRECATION_WARNINGS' '-D_LARGEFILE_SOURCE' '-D_FILE_OFFSET_BITS=64' '-DOPENSSL_NO_PINSHARED' '-DOPENSSL_THREADS' '-D__STDC_FORMAT_MACROS' '-DNAPI_DISABLE_CPP_EXCEPTIONS' '-DBUILDING_NODE_EXTENSION' -frtti -fexceptions -pthread -Wall -Wextra -Wno-unused-parameter -fno-omit-frame-pointer -I/usr/include/node-addon-api -I/usr/include/node -c hello/HelloMock.cpp -o hello/HelloMock.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 '-DNODE_GYP_MODULE_NAME=hello' '-DUSING_UV_SHARED=1' '-DUSING_V8_SHARED=1' '-DV8_DEPRECATION_WARNINGS=1' '-DV8_DEPRECATION_WARNINGS' '-DV8_IMMINENT_DEPRECATION_WARNINGS' '-D_LARGEFILE_SOURCE' '-D_FILE_OFFSET_BITS=64' '-DOPENSSL_NO_PINSHARED' '-DOPENSSL_THREADS' '-D__STDC_FORMAT_MACROS' '-DNAPI_DISABLE_CPP_EXCEPTIONS' '-DBUILDING_NODE_EXTENSION' -frtti -fexceptions -pthread -Wall -Wextra -Wno-unused-parameter -fno-omit-frame-pointer -I/usr/include/node-addon-api -I/usr/include/node -c hello/hello.cpp -o hello/hello.o
ar crs nothing.a nothing.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 ./hello/HelloSchema.o ./hello/HelloMock.o ./hello/hello.o -shared -Wl,-soname=hello.node -Wl,--start-group -lpthread -L/usr/local/lib/libgraphqlclient.a -L/usr/local/lib/libgraphqljson.a  -L/usr/local/lib/libgraphqlintrospection.a  -L/usr/local/lib/libgraphqlservice.a  -L/usr/local/lib/libgraphqlresponse.a  -L/usr/local/lib/libgraphqlpeg.a nothing.a -Wl,--end-group -o hello/hello.node


$ cat query.hello.graphql | node -p "require('./hello/hello.node').parseQuery();"
internal/modules/cjs/loader.js:1144
  return process.dlopen(module, path.toNamespacedPath(filename));
                 ^

Error: ./hello/hello.node: undefined symbol: _ZTIN7graphql7service6ObjectE
    at Object.Module._extensions..node (internal/modules/cjs/loader.js:1144:18)
    at Module.load (internal/modules/cjs/loader.js:950:32)
    at Function.Module._load (internal/modules/cjs/loader.js:790:12)
    at Module.require (internal/modules/cjs/loader.js:974:19)
    at require (internal/modules/cjs/helpers.js:93:18)
    at [eval]:1:1
    at Script.runInThisContext (vm.js:134:12)
    at Object.runInThisContext (vm.js:310:38)
    at internal/process/execution.js:81:19
    at [eval]-wrapper:6:22 {
  code: 'ERR_DLOPEN_FAILED'
}

[YJPrakash]

$ nm ./hello/hello.node | grep _ZTIN7graphql7service6ObjectE
                 U _ZTIN7graphql7service6ObjectE

[wravery]

It looks like you're hitting errors specific to Node/Electron Native Modules now. Building a working native module is complicated and fragile, I've had to spend a lot of time going through V8 headers to unblock major version upgrades of Electron using undocumented -D defines. The safest way I know to do this is to use npm and cmake-js instead of trying to build with make, cmake-js takes care of some of the cross-platform and major version incompatibilities for you. Otherwise, you may need to switch to gyp and electron-rebuild, which I think are the officially supported build systems for Electron.

All that aside, if you just want to pipe queries into an executable and get responses back, take a look at samples/today/sample.cpp. It works in interactive mode (stdin/stdout), or you can give it a file name for the query you want to execute.

[YJPrakash]

Yes, correct I am using Node addon API. An error is like an undefined symbol of GraphQL service. So only I am posting the above comment. Today I tried without Napi.h, my source compiled successfully including CFLAGS -shared -fPIC. But, segmentation-fault occurs when running that program $./hello/hello query.hello.graphql. Without using above mentioned flags I am getting the following errors when compiling. What does it mean about these errors?

g++ -std=gnu++17 -lgraphqlclient -lgraphqljson -lgraphqlintrospection -lgraphqlservice -lgraphqlresponse -lgraphqlpeg -c hello/HelloSchema.cpp -o hello/HelloSchema.o
g++ -std=gnu++17 -lgraphqlclient -lgraphqljson -lgraphqlintrospection -lgraphqlservice -lgraphqlresponse -lgraphqlpeg -c hello/HelloMock.cpp -o hello/HelloMock.o
g++ -std=gnu++17 -lgraphqlclient -lgraphqljson -lgraphqlintrospection -lgraphqlservice -lgraphqlresponse -lgraphqlpeg -c hello/hellosample.cpp -o hello/hellosample.o
ar crs nothing.a nothing.o
g++ -std=gnu++17 -pthread ./hello/hellosample.cpp -lpthread -lgraphqlclient -lgraphqljson -lgraphqlintrospection -lgraphqlservice -lgraphqlresponse -lgraphqlpeg -o hello/hellosample
/usr/bin/ld: /tmp/ccFl0ZhB.o: in function `void __gnu_cxx::new_allocator<graphql::hello::Query>::construct<graphql::hello::Query, main::{lambda()#1}>(graphql::hello::Query*, main::{lambda()#1}&&)':
hellosample.cpp:(.text+0x7fb): undefined reference to `graphql::hello::Query::Query(std::function<std::vector<std::shared_ptr<graphql::hello::Hello>, std::allocator<std::shared_ptr<graphql::hello::Hello> > > ()>&&)'
/usr/bin/ld: /tmp/ccFl0ZhB.o: in function `void __gnu_cxx::new_allocator<graphql::hello::Hello>::construct<graphql::hello::Hello, char const (&) [13]>(graphql::hello::Hello*, char const (&) [13])':
hellosample.cpp:(.text._ZN9__gnu_cxx13new_allocatorIN7graphql5hello5HelloEE9constructIS3_JRA13_KcEEEvPT_DpOT0_[_ZN9__gnu_cxx13new_allocatorIN7graphql5hello5HelloEE9constructIS3_JRA13_KcEEEvPT_DpOT0_]+0x79): undefined reference to `graphql::hello::Hello::Hello(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&&)'
/usr/bin/ld: /tmp/ccFl0ZhB.o: in function `void __gnu_cxx::new_allocator<graphql::hello::Operations>::construct<graphql::hello::Operations, std::shared_ptr<graphql::hello::Query>&>(graphql::hello::Operations*, std::shared_ptr<graphql::hello::Query>&)':
hellosample.cpp:(.text._ZN9__gnu_cxx13new_allocatorIN7graphql5hello10OperationsEE9constructIS3_JRSt10shared_ptrINS2_5QueryEEEEEvPT_DpOT0_[_ZN9__gnu_cxx13new_allocatorIN7graphql5hello10OperationsEE9constructIS3_JRSt10shared_ptrINS2_5QueryEEEEEvPT_DpOT0_]+0x69): undefined reference to `graphql::hello::Operations::Operations(std::shared_ptr<graphql::hello::object::Query>)'
/usr/bin/ld: /tmp/ccFl0ZhB.o: in function `graphql::hello::Hello::~Hello()':
hellosample.cpp:(.text._ZN7graphql5hello5HelloD2Ev[_ZN7graphql5hello5HelloD5Ev]+0x13): undefined reference to `vtable for graphql::hello::Hello'
collect2: error: ld returned 1 exit status
make: *** [makefile:107: hello/hellosample] Error 1

Please help me. In my project already we tried node-gyp build tool. All other(without node-addon) CPP files were compiled using the make utility. so we found a way to write the Node addon with make utility manually one make process. that's why I am using that above-mentioned make utility.

[wravery]

https://stackoverflow.com/questions/3065154/undefined-reference-to-vtable#:~:text=In%20summary%2C%20there%20are%20three%20key%20causes%20of,insufficient%20to%20cause%20the%20error%20on%20their%20own.

[YJPrakash]

$ make 
gcc -pthread -rdynamic -I/usr/include/node '-DUSING_UV_SHARED=1' '-DUSING_V8_SHARED=1' '-DV8_DEPRECATION_WARNINGS=1' '-DV8_DEPRECATION_WARNINGS' '-DV8_IMMINENT_DEPRECATION_WARNINGS' '-D_LARGEFILE_SOURCE' '-D_FILE_OFFSET_BITS=64' '-DOPENSSL_NO_PINSHARED' '-DOPENSSL_THREADS' '-D__STDC_FORMAT_MACROS' '-DNAPI_DISABLE_CPP_EXCEPTIONS' '-DBUILDING_NODE_EXTENSION' -c nothing.c -o nothing.o 
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -I./include -c src/GraphQLService.cpp -o src/GraphQLService.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -I./include -c src/Schema.cpp -o src/Schema.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -I./include -c src/Validation.cpp -o src/Validation.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -I./include -c src/Base64.cpp -o src/Base64.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -I./include -c src/GraphQLResponse.cpp -o src/GraphQLResponse.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -I./include -c src/SyntaxTree.cpp -o src/SyntaxTree.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -I./include -c src/JSONResponse.cpp -o src/JSONResponse.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -I./include -c src/Introspection.cpp -o src/Introspection.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -I./include -c src/IntrospectionSchema.cpp -o src/IntrospectionSchema.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -I./include -c src/GraphQLClient.cpp -o src/GraphQLClient.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -c hello/HelloSchema.cpp -o hello/HelloSchema.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -c hello/HelloMock.cpp -o hello/HelloMock.o
ar qc libhellographql.a  ./hello/HelloMock.o
ranlib libhellographql.a
ar qc libhelloschema.a  ./hello/HelloSchema.o
ranlib libhelloschema.a
ar qc libgraphqlclient.a  ./src/GraphQLClient.o
ranlib libgraphqlclient.a
ar qc libgraphqljson.a  ./src/JSONResponse.o
ranlib libgraphqljson.a
ar qc libgraphqlintrospection.a ./src/Introspection.o ./src/IntrospectionSchema.o
ranlib libgraphqlintrospection.a
ar qc libgraphqlservice.a ./src/GraphQLService.o ./src/Schema.o ./src/Validation.o
ranlib libgraphqlservice.a
ar qc libgraphqlresponse.a  ./src/Base64.o ./src/GraphQLResponse.o
ranlib libgraphqlresponse.a
ar qc libgraphqlpeg.a ./src/SyntaxTree.o
ranlib libgraphqlpeg.a
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 '-DNODE_GYP_MODULE_NAME=hello' '-DUSING_UV_SHARED=1' '-DUSING_V8_SHARED=1' '-DV8_DEPRECATION_WARNINGS=1' '-DV8_DEPRECATION_WARNINGS' '-DV8_IMMINENT_DEPRECATION_WARNINGS' '-D_LARGEFILE_SOURCE' '-D_FILE_OFFSET_BITS=64' '-DOPENSSL_NO_PINSHARED' '-DOPENSSL_THREADS' '-D__STDC_FORMAT_MACROS' '-DNAPI_DISABLE_CPP_EXCEPTIONS' '-DBUILDING_NODE_EXTENSION' -frtti -fexceptions -pthread -Wall -Wextra -Wno-unused-parameter -fno-omit-frame-pointer -I/usr/include/node-addon-api -I/usr/include/node -c hello/hello.cpp -o hello/hello.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -c hello/hellosample.cpp -o hello/hellosample.o
ar crs nothing.a nothing.o
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 -shared -Wl,-soname=hello.node -Wl,--start-group ./hello/hello.o libhellographql.a libhelloschema.a libgraphqlclient.a libgraphqljson.a libgraphqlintrospection.a libgraphqlservice.a libgraphqlresponse.a libgraphqlpeg.a -lpthread nothing.a -Wl,--end-group -o hello/hello.node
g++ -Os -O3 -fPIC -Ofast -std=gnu++17 ./hello/hellosample.o -o hello/hellosample.node libhellographql.a libhelloschema.a -lgraphqlclient -lgraphqljson -lgraphqlintrospection -lgraphqlservice -lgraphqlresponse -lgraphqlpeg -lpthread 

$ ./hello/hellosample.node query.hello.graphql 
1
Creating the query service...
Created the service...
Executing query...
{"data":{"hello":null},"errors":[{"message":"Field error name: hello unknown error: Query::getHello is not implemented","locations":[{"line":5,"column":5}],"path":["hello"]}]}

For Node addon fix:

$ nm ./hello/hello.node | grep _ZTIN7graphql7service6ObjectE
                 U _ZTIN7graphql7service6ObjectE

Node addon using libgraphqlservice.a. That was recompiled with -fPIC flags.
Finally, I am found a way to write node addon with Napi.h.

why I am getting the error "errors":[{"message":"Field error name: hello unknown error: Query::getHello is not implemented" throw from that executable?. But I am implementing that getHello function in HelloMock.cpp.
Please review my code.

HelloMock.h

#pragma once

#ifndef HELLOMOCK_H
#define HELLOMOCK_H

#include "HelloSchema.h"

#include <atomic>
#include <stack>

namespace graphql::hello
{
    struct RequestState : service::RequestState
    {
        RequestState(size_t id)
            : requestId(id)
        {
        }

        const size_t requestId;

        size_t greetsRequestId = 0;

        size_t greetsCount = 0;
    };

    class Hello;

    class Query : public object::Query
    {
        using helloLoader = std::function<std::vector<std::shared_ptr<Hello>>()>;

        public:
            explicit Query(helloLoader&& getHello);
            virtual service::FieldResult<std::optional<response::StringType>> getHello(const service::FieldParams&& params) const final;

        private:
            std::shared_ptr<Hello> findHello(const service::FieldParams &params) const;
            // Lazy load the fields in each query
            void loadHello(const std::shared_ptr<service::RequestState> &state) const;
            mutable helloLoader _getHello;
            mutable std::vector<std::shared_ptr<Hello>> _hello;
    };

    class Hello
    {
        public:
            explicit Hello(std::string&& greet);
            virtual service::FieldResult<std::optional<response::StringType>> getHello() final;
            virtual service::FieldResult<std::optional<response::StringType>> getForceError(
                service::FieldParams &&) const final
            {
                throw std::runtime_error(R"ex(this error was forced)ex");
            }

        private:
            std::string _greet;

        
    };

}

#endif // HELLOMOCK_H

HelloMock.cpp

#include "HelloMock.h"

#include <algorithm>
#include <iostream>

namespace graphql::hello
{

    Hello::Hello(std::string&& greet) : _greet(greet)
    {
    }
    service::FieldResult<std::optional<response::StringType>> Hello::getHello()
    {
        return _greet;
    }

    Query::Query(helloLoader&& getHello) 
    : _getHello(std::move(getHello))
    {
    }

    service::FieldResult<std::optional<response::StringType>> hello::Query::getHello(const service::FieldParams&& params) const
    {
        std::shared_ptr<Hello>  _hello = findHello(params);
        return _hello->getHello();
        // return _getHello();
    }
    
    void Query::loadHello(const std::shared_ptr<service::RequestState> &state) const
    {
        if (_getHello)
        {
            _hello = _getHello();
            _getHello = nullptr;
        }
    }

    std::shared_ptr<Hello> Query::findHello(const service::FieldParams &params) const
    {
        loadHello(params.state);
        // if(_hello != nullptr) return _hello;
        for (const auto &hello : _hello)
        {
            if (hello)
            {
                return hello;
            }
        }


        return nullptr;
    }

} // namespace graphql::hello

hellosample.cpp

#include "HelloMock.h"

#include "graphqlservice/JSONResponse.h"
#include <cstdio>
#include <iostream>
#include <iterator>
#include <stdexcept>

using namespace graphql;

int main(int argc, char **argv)
{
    std::cerr << "1" << std::endl;
    /* From HelloMock*/
    response::StringType helloKey;

    std::string fakeHelloKey("hello");
    helloKey.resize(fakeHelloKey.size());
    std::copy(fakeHelloKey.cbegin(), fakeHelloKey.cend(), helloKey.begin());
    
    std::cerr << "Creating the query service..." << std::endl;

    auto query = std::make_shared<hello::Query>(
        [&fakeHelloKey]() -> std::vector<std::shared_ptr<hello::Hello>>
        {
            std::cout << "Called getHello..." << std::endl;
            return {std::make_shared<hello::Hello>("Hello World!")};
        });

    auto service = std::make_shared<hello::Operations>(query);
    std::cout << "Created the service..." << std::endl;

    try
    {
        peg::ast query;
        if (argc > 1)
        {
            query = peg::parseFile(argv[1]);
        }
        else
        {
            std::istream_iterator<char> start{std::cin >> std::noskipws}, end{};
            std::string input{start, end};

            query = peg::parseString(std::move(input));
        }
        if (!query.root)
        {
            std::cerr << "Unknown error!" << std::endl;
            std::cerr << std::endl;
            return 1;
        }

        std::cout << "Executing query..." << std::endl;

        std::cout << response::toJSON(service
                                          ->resolve(nullptr,
                                                    query,
                                                    ((argc > 2) ? argv[2] : ""),
                                                    response::Value(response::Type::Map))
                                          .get())
                  << std::endl;
    }
    catch (const std::runtime_error &ex)
    {
        std::cerr << ex.what() << std::endl;
        return 1;
    }

    return 0;
}

https://stackoverflow.com/questions/3065154/undefined-reference-to-vtable#:~:text=In%20summary%2C%20there%20are%20three%20key%20causes%20of,insufficient%20to%20cause%20the%20error%20on%20their%20own.

It may helpful for implementing getHello function. I will take some time to read about it. Thank you for your help. @wravery

[wravery]

why I am getting the error "errors":[{"message":"Field error name: hello unknown error: Query::getHello is not implemented" throw from that executable?. But I am implementing that getHello function in HelloMock.cpp. Please review my code.

HelloMock.h

    class Query : public object::Query
    {
        using helloLoader = std::function<std::vector<std::shared_ptr<Hello>>()>;

        public:
            explicit Query(helloLoader&& getHello);
            virtual service::FieldResult<std::optional<response::StringType>> getHello(const service::FieldParams&& params) const final;

        private:
            std::shared_ptr<Hello> findHello(const service::FieldParams &params) const;
            // Lazy load the fields in each query
            void loadHello(const std::shared_ptr<service::RequestState> &state) const;
            mutable helloLoader _getHello;
            mutable std::vector<std::shared_ptr<Hello>> _hello;
    };

The getHello method should be declared with the final keyword and without the virtual keyword, so the compiler can tell you if you didn't override it properly. In this case, I think it will fail to override the stub because the signature doesn't match, you're taking a const service::FieldParams&& instead of service::FieldParams&&. I can't think of a reason why a move/r-value reference would be const, so you should probably just remove that.

The loader function is definitely too complicated for this purpose, TodayMock uses this for testing purposes (it's a test mock). A more realistic and better structured example is the learn sample based on the https://graphql.org tutorial, I'd suggest starting from there.

    class Hello
    {
        public:
            explicit Hello(std::string&& greet);
            virtual service::FieldResult<std::optional<response::StringType>> getHello() final;
            virtual service::FieldResult<std::optional<response::StringType>> getForceError(
                service::FieldParams &&) const final
            {
                throw std::runtime_error(R"ex(this error was forced)ex");
            }

        private:
            std::string _greet;

        
    };

This class Hello doesn't inherit from anything, so it should not have any virtual or final methods. That may be confusing gcc and contributing to the undefined reference to `vtable error.

https://stackoverflow.com/questions/3065154/undefined-reference-to-vtable#:~:text=In%20summary%2C%20there%20are%20three%20key%20causes%20of,insufficient%20to%20cause%20the%20error%20on%20their%20own.

It may helpful for implementing getHello function. I will take some time to read about it. Thank you for your help. @wravery

I should have clarified, that's a discussion specifically about the undefined reference to `vtable error. It has lots of great troubleshooting information.

[wravery]

Closing since I haven't heard anything for a couple of weeks. If you're still stuck, feel free to add more comments or open a new issue.