An implementation of GraphQL Service in C++, made from reference of official specifications! 😎
Prerequisites
Downloading CGQL
- Cloning using Git
git clone https://github.com/cgql/cgqlDoing this will clone the repository to your current working directory.
- Using tarball file ( *.tar.gz )
tar -xzvf <file-name>.tar.gzDownload the tarball file from release page and untar it using the above command.
- Using CGQL
CGQL is a statically linked library for Graphql which you can use on your own project to work with GraphQL in C++. That means you will have to link the library with your project
Suppose you have a folder structure like this:
project/
|-> src/
| |-> main.cpp
| |-> CMakeLists.txt
|-> lib/
| |-> cgql/ // this is the cloned / untar-ed cgql folder
| |-> CMakeLists.txt
|-> CMakeLists.txt
In the root level CMakeLists.txt add
cmake_minimum_required(VERSION 3.16)
project(next_billion_dollar_startup)
# basic configuration for project like C++ standard, etc...
/.../
add_subdirectory(src) # includes "your" source code
add_subdirectory(lib) # includes libraries for your projectThe CMakeLists.txt in lib should contain:
add_subdirectory(cgql)That's it... CGQL is included in your project like magic!
The CMakeLists.txt in src would contain something this:
project(Source)
add_executable(Source main.cpp)
target_link_libraries(
Source # your project
cgqlSource # the static library of cgql ( source )
)Yeah that's it now you can use CGQL in your project.
An example of executing a basic request
#include <cgql/cgql.h>
#include <cgql/parser/parser.h>
using namespace cgql;
int main() {
// configuration part
CgqlInstance test;
// schema
test.parseSchema(
"type Person {"
" name: String"
" age: Int"
"}"
""
"type Query {"
" person(id: Int): Person"
"}"
);
// resolvers
ResolverMap resolvers {
{
"person",
[](const Args& args) -> Data {
Int id = fromVariant<Int>(args["id"]); // argument
ResultMap p {
{
{ "name", "cw3dv" },
{ "age", 14 }
}
};
return cgqlSMakePtr<ResultMap>(p);
}
}
};
// TypeOfMap (used for abstract types)
TypeOfMap typeOfMap;
// query
auto query = parse(
"{"
" cw3dv: person {"
" name"
" age"
" }"
"}"
);
// execution
auto executionResult = test.executeWith(query, resolvers, typeOfMap);
printResultMap(*executionResult);
/* prints result to stdout
cw3dv
name cw3dv
age 14
*/
}Finally run:
cmake -B ./build/
cmake --build ./build/
./build/src/SourceOutput:
cw3dv
name cw3dv
age 14And there you go, you have a working GraphQL service... :) More to come like networking stuff, better error management, etc...