A GRM (GraphQL relation mapping), which is very similar to ORM, allowing users to quickly build a GraphQL server based on RDBMS (using kotlin and R2DBC)

If you use RDBMS to manage your persistent data, this framework can help you to quickly develop GraphQL services (based on kotlin and R2DBC) in the shortest time.

Its development speed is very fast, and the usage method is very simple.

1. It is a GRM (GraphQL-Relation mapping), and its usage is similar to ORM. When kotlin dsl is used to complete the mapping configuration between entities and tables, GraphQL objects and associations are automatically completed, including the runtime association-level DataLoader and related batch loading optimization.

2. It is easy to add user implemention fields to entity, where you can implement business-related calculations. User implementation fields can also enjoy the automatic generated DataLoader and related batch loading optimization at runtime.

3. Whether it is to implement query-level arguments or association-level arguments, you only need to use strongly typed SQL DSL to specify some dynamic filtering and sorting, and the rest is done automatically.

4. If you need pagination query, there is no development cost except changing the return type of ordinary query from List<T> to Connection<T>.

5. For mutation operations, the inputs type can be automatically generated according to a simple configuration, develpers only need to focus on entity objects, not input objects. At runtime, the framework can automatically convert the input object to a dynamic entity object tree and you only need one sentence to save any complex entity object tree to the database.

6. Integrated Spring security and JWT. Allows users to authorize by behavior, authorize by column, and authorize by row through the kotlin DSL.

View the video

https://www.youtube.com/watch?v=ky6HQQwo-3w

Run the example

Use intellij the open the example, after waiting for gradle to finish all tasks, start the program and visit http://localhost:8080/graphiql.

In order to experience this example, there are three things to note

1. Query.books is pagination query, so you must specify the argument "first" or "last", like this

   query {
     books(first: 10) {
       edges {
         node {
           name
         }
       }
     }
   }
   

   Otherwise, exeption will be thrown

   {
     "errors": [
       {
         "message": "java.lang.IllegalArgumentException: neither 'first' nor 'last' is specified",
         "locations": [],
         "path": [
           "books"
         ],
         "extensions": {
           "errorType": "INTERNAL"
         }
       }
     ],
     "data": {
       "books": null
     }
   }
   

2. BookStore.avgPrice, Query.myFavoriteBooks, Mutation.like and Mutation.unlike are not open to anonymous users

   Look at this query

   query {
     books(first: 10) {
       edges {
         node {
           name
           store {
             name
             avgPrice # Access BookStore.avgPrice
           }
         }
       }
     }
   }
   

   BookStore.avgPrice is not open to anonymous users, spring security throws AccessDeniedException when Authorization of HTTP request header is not specified.

   You can login

   • by graphql way

     query {
       login(email: "user1@gmail.com", password: "123456") {
         accessToken
       }
     }
     

   • or by rest way http://localhost:8080/authentication/login?email=user1@gmail.com&password=123456

   No matter which way you use, you can get the accessToken. Copy the accessToken and make the following HTTP header for the originally rejected graphql request

   { "Authorization": "...paste AccessToken here..."}
   

3. Mutation.saveBook, Mutation.saveBooks, Mutation.saveShallowTree and Mutation.saveBookDeepTree are only open to administrators.

   mutation {
     saveBook(input: {
       name: "NewBook",
       price: 70
     }) {
       id
     }
   }
   

   This mutation can only be executed by admininstor, spring security throws AccessDeniedException when the current user is not administrator.

   You can login as administrator (admin@gmail.com)

   • by graphql way

     query {
       login(email: "admin@gmail.com", password: "123456") {
         accessToken
       }
     }
     

   • or by rest way http://localhost:8080/authentication/login?email=admin@gmail.com&password=123456

   No matter which way you use, you can get the accessToken of administrator. Copy the accessToken of administrator and make the following HTTP header for the originally rejected graphql request

   { "Authorization": "...paste AccessToken of administrator here..."}
   

User guide & Documentation

These links are not only user guides, but also documentation.

Although the example allows you to quickly experience the working effect and quickly learn how to use the framework, these links still discuss some details that are not shown in the example.

1. Create project & Define entities
2. Map entities
3. Configure batch size
4. Add arguments to query
5. Add arguments to association
6. User-implemented fields
7. Pagination query
8. Map inputs
9. Execute Mutation
10. Security(Will come soon)

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Other projects

1. kimmer: A strongly typed SQL DSL base on kotlin, that is the basis of this framework.
2. graphql-ts-client. A strongly typed GraphQL DSL base on TypeScript, it's designed for web developers.