Break down your big monolitic GraphQl schema.js file into multiple files following the structure that makes sense to you and your team. SchemaGlue.js will glue all those files together for you ♥ ʘ‿ʘ.
Make your code more readable and understandable by breaking down your monolithic GraphQL schema and resolver into smaller domain models. SchemaGlue.js will help glueing them back together.
Without SchemaGlue - Stuck With a Monolithic Schema
- src/
|__ schema.js
- index.js
- package.json
With SchemaGlue - Structure Your Schema At Will
- src/
|__ graphql/
|__ product/
| |__ schema.graphql
| |__ resolver.js
|
|__ variant/
|__ schema.graphql
|__ resolver.js
- index.js
- package.json
npm install schemaglue --save
NOTICE: All the following examples use webfunc and graphql-serverless. graphql-serverless makes developing GraphQl server locally dead easy while webfunc is a serverless web framework that allows to write Express-like server to deploy them on any serverless solution.
const glue = require('schemaglue')
// This will look for any js files under the 'src/graphql' folder that
// comply to a certain convention described below. Those files describe
// bits and pieces of the GraphQL schema and resolver that schemaglue will
// reassemble into a single 'schema' string and 'resolver' object.
const options = {
ignore: '**/somefileyoudonotwant.js'
}
const { schema, resolver } = glue('src/graphql', options)PREREQUISITE - Install the following dependencies before running the following code:
npm install webfunc graphql-serverless schemaglue lodash --save
Project Structure Example
- src/
|__ schema.js
- index.js
- package.json
Where the schema.js file would contain the entire GraphQl schema and resolver definition:
// src/schema.js
const { graphqlError } = require('graphql-serverless')
const { makeExecutableSchema } = require('graphql-tools') // this dependency is automatically included in 'graphql-serverless'
const _ = require('lodash')
const schema = `
type Product {
id: ID!
name: String!
shortDescription: String
}
type Variant {
id: ID!
name: String!
shortDescription: String
}
type Query {
# ### GET products
#
# _Arguments_
# - **id**: Product id (optional)
products(id: Int): [Product]
# ### GET variants
#
# _Arguments_
# - **id**: Variant id (optional)
variants(id: Int): [Variant]
}
`
const productMocks = [{ id: 1, name: 'Product A', shortDescription: 'First product.' }, { id: 2, name: 'Product B', shortDescription: 'Second product.' }]
const productResolver = {
Query: {
products(root, { id }, context) {
const results = id ? productMocks.filter(p => p.id == id) : productMocks
if (results.length > 0)
return results
else
throw graphqlError(404, `Product with id ${id} does not exist.`)
}
}
}
const variantMocks = [{ id: 1, name: 'Variant A', shortDescription: 'First variant.' }, { id: 2, name: 'Variant B', shortDescription: 'Second variant.' }]
const variantResolver = {
Query: {
variants(root, { id }, context) {
const results = id ? variantMocks.filter(p => p.id == id) : variantMocks
if (results.length > 0)
return results
else
throw graphqlError(404, `Variant with id ${id} does not exist.`)
}
}
}
const executableSchema = makeExecutableSchema({
typeDefs: schema,
resolvers: _.merge(productResolver, variantResolver)
})
module.exports = {
executableSchema
}// index.js
const { graphqlHandler } = require('graphql-serverless')
const { app } = require('webfunc')
const { executableSchema } = require('./src/schema')
const graphqlOptions = {
schema: executableSchema,
graphiql: { // If you do not want to host any GraphiQl web interface, leave this property undefined.
endpoint: '/graphiql'
}
}
// Host a GraphQl API on 2 endpoints: '/' and '/graphiql'. '/graphiql' is used to host the GraphiQL web interface.
// If you're not interested in the GraphiQl web interface, leave the above 'graphqlOptions.graphiql' undefined and
// replace the path following ['/', '/graphiql'] with '/'.
app.all(['/', '/graphiql'], graphqlHandler(graphqlOptions))
// Starting the server
eval(app.listen('app', 4000))Simply run node index.js and then browse to http://localhost:4000/graphiql.
PREREQUISITE - Install the following dependencies before running the following code:
npm install webfunc graphql-serverless schemaglue lodash --save
Project Structure Example
- src/
|__ graphql/
|__ product/
| |__ schema.graphql
| |__ resolver.js
|
|__ variant/
|__ schema.graphql
|__ resolver.js
- index.js
- package.json
This is just one example of how to structure the schema and resolver. schemaglue looks for all .js and .graphql files under a specific path.
// src/graphql/product/schema.graphql
type Product {
id: ID!
name: String!
shortDescription: String
}
type Query {
# ### GET products
#
# _Arguments_
# - **id**: Product id (optional)
products(id: Int): [Product]
}// src/graphql/product/resolver.js
const { graphqlError } = require('graphql-serverless')
const productMocks = [{ id: 1, name: 'Product A', shortDescription: 'First product.' }, { id: 2, name: 'Product B', shortDescription: 'Second product.' }]
exports.resolver = {
Query: {
products(root, { id }, context) {
const results = id ? productMocks.filter(p => p.id == id) : productMocks
if (results.length > 0)
return results
else
throw graphqlError(404, `Product with id ${id} does not exist.`)
}
}
}// src/graphql/variant/schema.graphql
type Variant {
id: ID!
name: String!
shortDescription: String
}
type Query {
# ### GET variants
#
# _Arguments_
# - **id**: Variant id (optional)
variants(id: Int): [Variant]
}// src/graphql/variant/resolver.js
const { graphqlError } = require('graphql-serverless')
const variantMocks = [{ id: 1, name: 'Variant A', shortDescription: 'First variant.' }, { id: 2, name: 'Variant B', shortDescription: 'Second variant.' }]
exports.resolver = {
Query: {
variants(root, { id }, context) {
const results = id ? variantMocks.filter(p => p.id == id) : variantMocks
if (results.length > 0)
return results
else
throw graphqlError(404, `Variant with id ${id} does not exist.`)
}
}
}// index.js
const { graphqlHandler } = require('graphql-serverless')
const { app } = require('webfunc')
const { makeExecutableSchema } = require('graphql-tools')
const glue = require('schemaglue')
const { schema, resolver } = glue('src/graphql')
const executableSchema = makeExecutableSchema({
typeDefs: schema,
resolvers: resolver
})
const graphqlOptions = {
schema: executableSchema,
graphiql: {
endpoint: '/graphiql'
}
}
app.all(['/', '/graphiql'], graphqlHandler(graphqlOptions))
eval(app.listen('app', 4000))Simply run node index.js and then browse to http://localhost:4000/graphiql.
In some cases, you might want to ignore some specific files under the schema folder (by default, SchemaGlue will take into account all .js files). SchemaGlue adds support to ignore files or folders using globbing:
const { schema, resolver } = glue('./src/graphql', { ignore: '**/somefile.js' })This will take into account all .js files under the folder ./src/graphql, excluding all somefile.js files. The ignore property supports both a single string or an array of strings.
// Ignore more than 1 specific .js file
const { schema:schema1 } = glue('./src/graphql', { ignore: ['**/somefile.js', '**/someotherfile.js'] })
// Ignore all files under the ./src/graphql/variant folder
const { schema:schema1 } = glue('./src/graphql', { ignore: 'variant/**' })Unions & Interfaces
If you're not familiar with this concept, check out this great article GraphQL Tour: Interfaces and Unions.
In our case, we're interested is knowing how to structure our code with unions or interfaces. If your schema is small, I would recommend to manage your unions and intefaces definitions inside a single schema.js file per model:
- src/
|__ graphql/
|__ product/
| |__ schema.graphql
| |__ resolver.js
|
|__ variant/
|__ schema.graphql
|__ resolver.js
- index.js
- package.json
Let's take the schema.graphql and resolver.js under src/graphql/product/ as an example:
schema.graphql
union Product = Bicycle | Racket
type Bicycle {
id: ID!
brand: String!
wheels: Int!
}
type Racket {
id: ID!
brand: String!
sportType: SportType!
}
enum SportType {
TENNIS
SQUASH
}
type Query {
# ### GET products
#
# _Arguments_
# - **id**: Product id (optional)
products(id: Int): [Product]
}resolver.js
const { graphqlError } = require('graphql-serverless')
const productMocks = [{
id: 1,
brand: 'Giant',
wheels: 2
},{
id: 2,
brand: 'Prince',
sportType: 'TENNIS'
}]
exports.resolver = {
Query: {
products(root, { id }, context) {
const results = id ? productMocks.filter(p => p.id == id) : productMocks
if (results.length > 0)
return results
else
throw graphqlError(404, `Product with id ${id} does not exist.`)
}
},
Product: {
__resolveType(obj, context, info) {
return obj.wheels ? 'Bicycle' :
obj.sportType ? 'Racket' : null
}
}
}Notice you need to define a resolveType method for the Product type under the exports.resolver
We are Neap, an Australian Technology consultancy powering the startup ecosystem in Sydney. We simply love building Tech and also meeting new people, so don't hesitate to connect with us at https://neap.co.
Our other open-sourced projects:
- webfunc: Write code for serverless similar to Express once, deploy everywhere.
- now-flow: Automate your Zeit Now Deployments.
- graphql-serverless: GraphQL (incl. a GraphiQL interface) middleware for webfunc.
- schemaglue: Naturally breaks down your monolithic graphql schema into bits and pieces and then glue them back together.
- graphql-s2s: Add GraphQL Schema support for type inheritance, generic typing, metadata decoration. Transpile the enriched GraphQL string schema into the standard string schema understood by graphql.js and the Apollo server client.
- graphql-authorize: Authorization middleware for graphql-serverless. Add inline authorization straight into your GraphQl schema to restrict access to certain fields based on your user's rights.
- react-native-game-engine: A lightweight game engine for react native.
- react-native-game-engine-handbook: A React Native app showcasing some examples using react-native-game-engine.
- aws-cloudwatch-logger: Promise based logger for AWS CloudWatch LogStream.
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