graphql-sequelize-bds
v0.22.0-bds.1
Published
GraphQL & Relay for MySQL & Postgres via Sequelize
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Readme
graphql-sequelize
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
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';
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: {}
});
/*
{
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
})
}