graphql

README

How to create step by step

this is a test about implementing the graphql over PostgreSQL Sample Database. if you want to run this application follow prerequisites.

Setup a New application From Scratch

• Step-1 : Initialize the Module

  like any other new project in go.

    go mod init github.com/go-related/graphql
  

• Step-2 : Get the graph package

  In order to create a graphQl project first we need to load tha package which can be done using the command below:

    go get github.com/99designs/gqlgen
  

• Step-3 : Initialize graph project, generate folder structures

  this creates the graph folder and internal structures.

    go run github.com/99designs/gqlgen init
  

• Step-4 : Add the db package and update the resolver

  I prefer to work base on interface so my application doesn't know or care on the implementation of the persistence layer. I recommend this way since it's compliant to solid principles, and it's easier to mock the db. Here this is implemented on persistance package:

        type LibraryDb interface {
      CreateAuthor(ctx context.Context, data model.Author) (model.Author, error)
      UpdateAuthor(ctx context.Context, data model.Author) error
      DeleteAuthor(ctx context.Context, Id uint) error
      GetAllAuthors(ctx context.Context) ([]*model.Author, error)
      GetAuthorById(ctx context.Context, Id uint) (*model.Author, error)
  }
    type libraryDb struct {
      Db *gorm.DB
  }
  
  func NewLibraryDb(connectionString string) (LibraryDb, error){}
  

  and on the resolver.go (graph/resolver.go) we update the dependency

    package graph
  
    import "github.com/go-related/graphql/persistance"
  
    type Resolver struct {
    DB persistance.LibraryDb
    }
  
  

• Step-5 : Update the schema for queries and mutation

  The file can be found at graph/schema.graphqls
  After adding out types/query/mutation we run the following command to update the corresponding models

    go run github.com/99designs/gqlgen generate
  

• Step-6 : Run the application

      #cd project root
      go run internal/server.go