json-graphql-server

Get a full fake GraphQL API with zero coding in less than 30 seconds.

Motivation

I'd love to learn GraphQL, but it seems that I first have to read a book about GraphQL Types and Queries, then install a gazillion npm packages.

• About every developer

Start playing with GraphQL right away with json-graphql-server, a testing and mocking tool for GraphQL. All it takes is a JSON of your data.

Inspired by the excellent json-server.

Example

Follow the guide below starting from scratch, or see the example live on StackBlitz:

Create a db.js file.

Your data file should export an object where the keys are the entity types. The values should be lists of entities, i.e. arrays of value objects with at least an id key. For instance:

module.exports = {
    posts: [
        { id: 1, title: "Lorem Ipsum", views: 254, user_id: 123 },
        { id: 2, title: "Sic Dolor amet", views: 65, user_id: 456 },
    ],
    users: [
        { id: 123, name: "John Doe" },
        { id: 456, name: "Jane Doe" }
    ],
    comments: [
        { id: 987, post_id: 1, body: "Consectetur adipiscing elit", date: new Date('2017-07-03') },
        { id: 995, post_id: 1, body: "Nam molestie pellentesque dui", date: new Date('2017-08-17') }
    ]
}

Start the GraphQL server on localhost, port 3000.

json-graphql-server db.js

To use a port other than 3000, you can run json-graphql-server db.js --p <your port here> To use a host other than localhost, you can run json-graphql-server db.js -h <your host here> or --host <your host here>

Now you can query your data in graphql. For instance, to issue the following query:

{
    Post(id: 1) {
        id
        title
        views
        User {
            name
        }
        Comments {
            date
            body
        }
    }
}

Go to http://localhost:3000/?query=%7B%20Post%28id%3A%201%29%20%7B%20id%20title%20views%20User%20%7B%20name%20%7D%20Comments%20%7B%20date%20body%20%7D%20%7D%20%7D. You'll get the following result:

{
    "data": {
        "Post": {
            "id": "1",
            "title": "Lorem Ipsum",
            "views": 254,
            "User": {
                "name": "John Doe"
            },
            "Comments": [
                { "date": "2017-07-03T00:00:00.000Z", "body": "Consectetur adipiscing elit" },
                { "date": "2017-08-17T00:00:00.000Z", "body": "Nam molestie pellentesque dui" },
            ]
        }
    }
}

The json-graphql-server accepts queries in GET and POST. Under the hood, it uses the graphql-http module. Please refer to their documentations for details about passing variables, etc.

Note that the server is GraphiQL enabled, so you can query your server using a full-featured graphical user interface, providing autosuggest, history, etc. Just browse http://localhost:3000/ to access it.

Install

npm install -g json-graphql-server

Generated Types and Queries

Based on your data, json-graphql-server will generate a schema with one type per entity, as well as 3 query types and 3 mutation types. For instance for the Post entity:

type Query {
  Post(id: ID!): Post
  allPosts(page: Int, perPage: Int, sortField: String, sortOrder: String, filter: PostFilter): [Post]
  _allPostsMeta(page: Int, perPage: Int, sortField: String, sortOrder: String, filter: PostFilter): ListMetadata
}
type Mutation {
  createPost(data: String): Post
  createManyPost(data: [{data:String}]): [Post]
  updatePost(data: String): Post
  removePost(id: ID!): Post
}
type Post {
    id: ID!
    title: String!
    views: Int!
    user_id: ID!
    User: User
    Comments: [Comment]
}
type PostFilter {
    q: String
    id: ID
    id_neq: ID
    title: String
    title_neq: String
    views: Int
    views_lt: Int
    views_lte: Int
    views_gt: Int
    views_gte: Int
    views_neq: Int
    user_id: ID    
    user_id_neq: ID
}
type ListMetadata {
    count: Int!
}
scalar Date

By convention, json-graphql-server expects all entities to have an id field that is unique for their type - it's the entity primary key. The type of every field is inferred from the values, so for instance, Post.title is a String!, and Post.views is an Int!. When all entities have a value for a field, json-graphql-server makes the field type non nullable (that's why Post.views type is Int! and not Int).

For every field named *_id, json-graphql-server creates a two-way relationship, to let you fetch related entities from both sides. For instance, the presence of the user_id field in the posts entity leads to the ability to fetch the related User for a Post - and the related Posts for a User.

The all* queries accept parameters to let you sort, paginate, and filter the list of results. You can filter by any field, not just the primary key. For instance, you can get the posts written by user 123. Json-graphql-server also adds a full-text query field named q, and created range filter fields for numeric and date fields. All types (excluding booleans and arrays) get a not equal filter. The detail of all available filters can be seen in the generated *Filter type.

Supported types

Type	GraphQL Type	Rule	Example value
Id	GraphQLID	name === 'id' || name.substr(name.length - 3) === '_id'	1
Integer	GraphQLInt	Number.isInteger(value)	12
Numeric	GraphQLFloat	!isNaN(parseFloat(value)) && isFinite(value)	12.34
Boolean	GraphQLBoolean	typeof value === 'boolean'	false
String	GraphQLString	typeof value === 'string'	'foo'
Array	GraphQLList	Array.isArray(value)	['bar'], [12, 34]
Date	DateType (custom)	value instanceof Date || isISODateString(value)	new Date('2016-06-10T15:49:14.236Z'), '2016-06-10T15:49:14.236Z'
Object	GraphQLJSON	Object.prototype.toString.call(value) === '[object Object]'	transport: { service: 'fakemail', auth: { user: '[email protected]', pass: 'f00b@r' } }

GraphQL Usage

Here is how you can use the queries and mutations generated for your data, using Post as an example:

Query / Mutation	Result
// get a single entity, by id { Post(id: 1) { id title views user_id } }	{ "data": { "Post": { "id": 1, "title": "Lorem Ipsum", "views": 254, "user_id": 123 } } }
// include many-to-one relationships { Post(id: 1) { title User { name } } }	{ "data": { "Post": { "title": "Lorem Ipsum", "User": { "name": "John Doe" } } } }
// include one-to-many relationships { Post(id: 1) { title Comments { body } } }	{ "data": { "Post": { "title": "Lorem Ipsum", "Comments": [ { "body": "Consectetur adipiscing elit" }, { "body": "Nam molestie pellentesque dui" }, ] } } }
// get a list of entities for a type { allPosts { title views } }	{ "data": { "allPosts": [ { "title": "Lorem Ipsum", views: 254 }, { "title": "Sic Dolor amet", views: 65 } ] } }
// paginate the results { allPosts(page: 0, perPage: 1) { title views } }	{ "data": { "allPosts": [ { "title": "Lorem Ipsum", views: 254 }, ] } }
// sort the results by field { allPosts(sortField: "title", sortOrder: "desc") { title views } }	{ "data": { "allPosts": [ { "title": "Sic Dolor amet", views: 65 } { "title": "Lorem Ipsum", views: 254 }, ] } }
// filter the results using the full-text filter { allPosts(filter: { q: "lorem" }) { title views } }	{ "data": { "allPosts": [ { "title": "Lorem Ipsum", views: 254 }, ] } }
// filter the result using any of the entity fields { allPosts(filter: { views: 254 }) { title views } }	{ "data": { "allPosts": [ { "title": "Lorem Ipsum", views: 254 }, ] } }
// all fields (except boolean and array) get not equal filters // -lt, _lte, -gt, and _gte { allPosts(filter: { title_neq: "Lorem Ipsum" }) { title views } }	{ "data": { "allPosts": [ { "title": "Some Other Title", views: 254 }, ] } }
// number fields get range filters // -lt, _lte, -gt, and _gte { allPosts(filter: { views_gte: 200 }) { title views } }	{ "data": { "allPosts": [ { "title": "Lorem Ipsum", views: 254 }, ] } }

Usage with Node

Install the module locally:

npm install --save-dev json-graphql-server

Then use the jsonGraphqlExpress express middleware:

import express from 'express';
import jsonGraphqlExpress from 'json-graphql-server/node';

const PORT = 3000;
const app = express();
const data = {
    // ... your data
};

app.use('/graphql', jsonGraphqlExpress.default(data));
app.listen(PORT);

Usage in browser with XMLHttpRequest

Useful when using XMLHttpRequest directly or libraries such as axios.

Install with a script tag

Add a script tag referencing the library:

<script src="../dist/json-graphql-server.umd.js"></script>

It will expose the JsonGraphqlServer as a global object:

<script type="text/javascript">
    window.addEventListener('load', function() {
        const data = [...];

        const server = JsonGraphqlServer({
            data,
            url: 'http://localhost:3000/graphql'
        });

        server.start();

        const xhr = new XMLHttpRequest();
        xhr.open('POST', 'http://localhost:3000/graphql', true);
        xhr.setRequestHeader('Content-Type', 'application/json');
        xhr.setRequestHeader('Accept', 'application/json');
        xhr.onerror = function(error) {
            console.error(error);
        }
        xhr.onload = function() {
            const result = JSON.parse(xhr.responseText);
            console.log('data returned:', result);
            alert('Found ' + result.data.allPosts.length + ' posts');
        }
        const body = JSON.stringify({ query: 'query allPosts { allPosts { id } }' });
        xhr.send(body);
    });
</script>

Use with a bundler (webpack)

npm install json-graphql-server

import JsonGraphqlServer from 'json-graphql-server';

const data = [...];

const server = JsonGraphqlServer({
    data,
    url: 'http://localhost:3000/graphql'
});

server.start();

const xhr = new XMLHttpRequest();
xhr.open('POST', 'http://localhost:3000/graphql', true);
xhr.setRequestHeader('Content-Type', 'application/json');
xhr.setRequestHeader('Accept', 'application/json');
xhr.onerror = function(error) {
    console.error(error);
}
xhr.onload = function() {
    const result = JSON.parse(xhr.responseText);
    console.log('data returned:', result);
    alert('Found ' + result.data.allPosts.length + ' posts');
}
const body = JSON.stringify({ query: 'query allPosts { allPosts { id } }' });
xhr.send(body);

Usage in browser with fetch

import fetchMock from 'fetch-mock';
import JsonGraphqlServer from 'json-graphql-server';

const data = [...];
const server = JsonGraphqlServer({ data });

fetchMock.post('http://localhost:3000/graphql', server.getHandler());

fetch({
    url: 'http://localhost:3000/graphql',
    method: 'POST',
    body: JSON.stringify({ query: 'query allPosts { allPosts { id } }' })
})
.then(response => response.json())
.then(json => {
    alert('Found ' + result.data.allPosts.length + ' posts');
})

Adding Authentication, Custom Routes, etc.

json-graphql-server doesn't deal with authentication or custom routes. But you can use your favorite middleware with Express:

import express from 'express';
import jsonGraphqlExpress from 'json-graphql-server';

import OAuthSecurityMiddleWare from './path/to/OAuthSecurityMiddleWare';

const PORT = 3000;
const app = express();
const data = {
    // ... your data
};
app.use(OAuthSecurityMiddleWare());
app.use('/graphql', jsonGraphqlExpress(data));
app.listen(PORT);

Schema Export

You can also use the export jsonSchemaBuilder to get your own copy of the GraphQLSchema:

In node:

import {graphql} from 'graphql';
import {jsonSchemaBuilder} from 'json-graphql-server';

const data = { };
const schema = jsonSchemaBuilder(data);
const query = `[...]`

graphql(schema, query).then(result => {
  console.log(result);
});

Or available in the global scope when running on a client as jsonSchemaBuilder.

Plain Schema

If you want to use another server type instead of the built in graphql express, like apollo-server or etc, you can expose the plain schema to be built into an executable schema (there may be version issues otherwise).

This uses the export getPlainSchema.

import { ApolloServer } from 'apollo-server';
import { makeExecutableSchema } from '@graphql-tools/schema'; // or graphql-tools
import { applyMiddleware } from 'graphql-middleware';
import { getPlainSchema } from 'json-graphql-server';

const data = { };

// Example middlewares
const logInput = async (resolve, root, args, context, info) => {
    console.log(`1. logInput: ${JSON.stringify(args)}`);
    const result = await resolve(root, args, context, info);
    console.log(`5. logInput`);
    return result;
};
const logResult = async (resolve, root, args, context, info) => {
    console.log(`2. logResult`);
    const result = await resolve(root, args, context, info);
    console.log(`4. logResult: ${JSON.stringify(result)}`);
    return result;
};

// Leverage getPlainSchema
const schema = applyMiddleware(
    makeExecutableSchema(getPlainSchema(data)),
    logInput,
    logResult
);
const server = new ApolloServer({
    schema,
});
server.listen({ port: 3000 });

Deployment

Deploy with Heroku or Next.js.

Roadmap

• CLI options (https, watch, delay, custom schema)
• Subscriptions
• Client-side mocking (à la FakeRest)

Contributing

Use Prettier formatting and make sure you include unit tests. The project includes a Makefile to automate usual developer tasks:

make install
make build
make test
make watch
make format

To learn more about the contributions to this project, consult the contribution guide.

Maintainers

Francois Zaninotto	Gildas Garcia	Alexis Janvier

License

json-graphql-server is licensed under the MIT Licence, sponsored and supported by marmelab.