@idris/graphql-sequelize

graphql-sequelize

• Installation
• Resolve helpers
• field helpers
• args helpers

Installation

$ npm install --save graphql-sequelize

graphql-sequelize assumes you have graphql and sequelize installed.

Resolve helpers

A helper for resolving graphql queries targeted at Sequelize models or associations. Please take a look at the tests to best get an idea of implementation.

Attribute filtering

The graphql-sequelize resolver will by default only select those attributes requested from the database.

If you have non-database values that depend on other values you can either solve this by using virtual attributes with dependencies on your model or disable attribute filtering via resolver.filterAttributes = false or for specific resolvers with resolver(target, {filterAttributes: false}).

Default attributes

When filtering attributes you might need some fields every time, regardless of wether they have been requested in the query. You can specify those fields with the defaultAttributes resolver option like resolver(target, {defaultAttributes: ['default', 'field', 'names']}). A common use case would be the need to fetch a userId for every query and every resource of your domain model for permission checking -- in that case you would write your resolver functions like resolver(target, {defaultAttributes: ['userId']}).

Features

• Automatically converts args to where if arg keys matches model attributes
• Automatically converts a arg named 'limit' to a sequelize limit
• Automatically converts a arg named 'order' to a sequelize order
• Only loads the attributes defined in the query (automatically adds primary key and foreign keys)
• Prefetching nested resolvers with includes/joins

Relay & Connections

Relay documentation

Examples

import {resolver} from 'graphql-sequelize';

let User = sequelize.define('user', {
  name: Sequelize.STRING
});

let Task = sequelize.define('task', {
  title: Sequelize.STRING
});

User.Tasks = User.hasMany(Task, {as: 'tasks'});

let taskType = new GraphQLObjectType({
  name: 'Task',
  description: 'A task',
  fields: {
    id: {
      type: new GraphQLNonNull(GraphQLInt),
      description: 'The id of the task.',
    },
    title: {
      type: GraphQLString,
      description: 'The title of the task.',
    }
  }
});

let userType = new GraphQLObjectType({
  name: 'User',
  description: 'A user',
  fields: {
    id: {
      type: new GraphQLNonNull(GraphQLInt),
      description: 'The id of the user.',
    },
    name: {
      type: GraphQLString,
      description: 'The name of the user.',
    },
    tasks: {
      type: new GraphQLList(taskType),
      resolve: resolver(User.Tasks, {
        separate: true // load seperately, disables auto including - default: false
      })
    }
  }
});

let schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: 'RootQueryType',
    fields: {
      user: {
        type: userType,
        // args will automatically be mapped to `where`
        args: {
          id: {
            description: 'id of the user',
            type: new GraphQLNonNull(GraphQLInt)
          }
        },
        resolve: resolver(User, {
          include: false // disable auto including of associations based on AST - default: true
        })
      }
    }
  })
});

let schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: 'RootQueryType',
    fields: {
      users: {
        // The resolver will use `findOne` or `findAll` depending on whether the field it's used in is a `GraphQLList` or not.
        type: new GraphQLList(userType),
        args: {
          // An arg with the key limit will automatically be converted to a limit on the target
          limit: {
            type: GraphQLInt
          },
          // An arg with the key order will automatically be converted to a order on the target
          order: {
            type: GraphQLString
          }
        },
        resolve: resolver(User)
      }
    }
  })
});

field helpers

field helpers help you automatically define a models attributes as fields for a GraphQL object type.

var Model = sequelize.define('User', {
  email: {
    type: Sequelize.STRING,
    allowNull: false
  },
  firstName: {
    type: Sequelize.STRING
  },
  lastName: {
    type: Sequelize.STRING
  }
});

import {attributeFields} from 'graphql-sequelize';

var cache = {}; // Reusable cache of enum types
attributeFields(Model, {
  // ... options
  exclude: [], // array of model attributes to ignore - default: []
  only: [], // only generate definitions for these model attributes - default: null
  globalId: true, // return an relay global id field - default: false
  map: {}, // rename fields - default: {}
  allowNull: false, // disable wrapping mandatory fields in `GraphQLNonNull` - default: false
  commentToDescription: false, // convert model comment to GraphQL description - default: false
  cache: cache, // Cache enum types to prevent duplicate type name error - default: {}
});

/*
{
  id: {
    type: new GraphQLNonNull(GraphQLInt)
  },
  email: {
    type: new GraphQLNonNull(GraphQLString)
  },
  firstName: {
    type: GraphQLString
  },
  lastName: {
    type: GraphQLString
  }
}
*/

userType = new GraphQLObjectType({
  name: 'User',
  description: 'A user',
  fields: _.assign(attributeFields(Model), {
    // ... extra fields
  })
});

Providing custom types

attributeFields uses the graphql-sequelize typeMapper to map Sequelize types to GraphQL types. You can supply your own mapping function to override this behavior using the mapType export.

var Model = sequelize.define('User', {
  email: {
    type: Sequelize.STRING,
    allowNull: false
  },
  isValid: {
    type: Sequelize.BOOLEAN,
    allowNull: false
  }
});

import {attributeFields,typeMapper} from 'graphql-sequelize';
typeMapper.mapType((type) => {s
   //map bools as strings
   if (type instanceof Sequelize.BOOLEAN) {
     return GraphQLString
   }
   //use default for everything else
   return false
});

//map fields
attributeFields(Model);

/*
{
  id: {
    type: new GraphQLNonNull(GraphQLInt)
  },
  email: {
    type: new GraphQLNonNull(GraphQLString)
  },
  isValid: {
      type: new GraphQLNonNull(GraphQLString)
  },
}
*/

Renaming generated fields

attributeFields accepts a map option to customize the way the attribute fields are named. The map option accepts an object or a function that returns a string.

var Model = sequelize.define('User', {
  email: {
    type: Sequelize.STRING,
    allowNull: false
  },
  firstName: {
    type: Sequelize.STRING
  },
  lastName: {
    type: Sequelize.STRING
  }
});

attributeFields(Model, {
    map:{
        email:"Email",
        firstName:"FirstName",
        lastName:"LastName"
    }
});

/*
{
  id: {
    type: new GraphQLNonNull(GraphQLInt)
  },
  Email: {
    type: new GraphQLNonNull(GraphQLString)
  },
  FirstName: {
    type: GraphQLString
  },
  LastName: {
    type: GraphQLString
  }
}
*/

attributeFields(Model, {
    map:(k) => k.toLowerCase()
});

/*
{
  id: {
    type: new GraphQLNonNull(GraphQLInt)
  },
  email: {
    type: new GraphQLNonNull(GraphQLString)
  },
  firstname: {
    type: GraphQLString
  },
  lastname: {
    type: GraphQLString
  }
}
*/

ENUM attributes with non-alphanumeric characters

GraphQL enum types only support ASCII alphanumeric characters and underscores. If you have other characters, like a dash (-) in your Sequelize enum types, they will be converted to camelCase. For example: foo-bar becomes fooBar.

VIRTUAL attributes and GraphQL fields

If you have Sequelize.VIRTUAL attributes on your sequelize model, you need to explicitly set the return type and any field dependencies via new Sequelize.VIRTUAL(returnType, [dependencies ... ]).

For example, fullName here will not always return valid data when queried via GraphQL:

firstName: { type: Sequelize.STRING },
lastName: { type: Sequelize.STRING },
fullName: {
  type: Sequelize.VIRTUAL,
  get: function() { return `${this.firstName} ${this.lastName}`; },
},

To work properly fullName needs to be more fully specified:

firstName: { type: Sequelize.STRING },
lastName: { type: Sequelize.STRING },
fullName: {
  type: new Sequelize.VIRTUAL(Sequelize.STRING, ['firstName', 'lastName']),
  get: function() { return `${this.firstName} ${this.lastName}`; },
},

args helpers

defaultArgs

defaultArgs(Model) will return an object containing an arg with a key and type matching your models primary key and the "where" argument for passing complex query operations described here

var Model = sequelize.define('User', {

});

defaultArgs(Model);

/*
{
  id: {
    type: new GraphQLNonNull(GraphQLInt)
  }
}
*/

var Model = sequelize.define('Project', {
  project_id: {
    type: Sequelize.UUID
  }
});

defaultArgs(Model);

/*
{
  project_id: {
    type: GraphQLString
  },
   where: {
      type JSONType
  }
}
*/

defaultListArgs

defaultListArgs will return an object like:

{
  limit: {
    type: GraphQLInt
  },
  order: {
    type: GraphQLString
  },
  where: {
    type JSONType
  }
}

Which when added to args will let the resolver automatically support limit and ordering in args for graphql queries. Should be used with fields of type GraphQLList.

import {defaultListArgs} from 'graphql-sequelize'

args: {
  _.assign(defaultListArgs(), {
    // ... additional args
  })
}