ra-data-loopback4

Loopback 4 Data Provider For React-Admin

Loopback 4 Data Provider for react-admin, the frontend framework for building admin applications on top of REST/GraphQL services.

Code is nearly identical to ra-data-json-server.

Installation

npm install --save ra-data-loopback4

REST Dialect

This Data Provider fits REST APIs powered by JSON Server, such as JSONPlaceholder.

REST verb	API calls
GET_LIST	GET http://my.api.url/posts?_sort=title&_order=ASC&_start=0&_end=24&title=bar
GET_ONE	GET http://my.api.url/posts/123
CREATE	POST http://my.api.url/posts/123
UPDATE	PUT http://my.api.url/posts/123
DELETE	DELETE http://my.api.url/posts/123
GET_MANY	GET http://my.api.url/posts/123, GET http://my.api.url/posts/456, GET http://my.api.url/posts/789
GET_MANY_REFERENCE	GET http://my.api.url/posts?author_id=345

Note: Normally, ra-data-json-server module would require X-Total-Count hader from response to GET_LIST calls. This module calls {resource}/count routes for each pagination calls and then adds the X-Total-Count header to a subsequence GET_LIST call.

If your API is on another domain as the JS code, you'll need to whitelist this header with an Access-Control-Expose-Headers CORS header.

Access-Control-Expose-Headers: X-Total-Count

Usage

// in src/App.js
import React from 'react';
import { Admin, Resource } from 'react-admin';
import loopbackFourProvider from 'ra-data-loopback4';
 
import { PostList } from './posts';
 
const App = () => (
    <Admin dataProvider={jsonServerProvider('http://jsonplaceholder.typicode.com')}>
        <Resource name="posts" list={PostList} />
    </Admin>
);
 
export default App;

Adding Custom Headers

The provider function accepts an HTTP client function as second argument. By default, they use react-admin's fetchUtils.fetchJson() as HTTP client. It's similar to HTML5 fetch(), except it handles JSON decoding and HTTP error codes automatically.

That means that if you need to add custom headers to your requests, you just need to wrap the fetchJson() call inside your own function:

import { fetchUtils, Admin, Resource } from 'react-admin';
import loopbackFourProvider from 'ra-data-loopback4';
 
const httpClient = (url, options = {}) => {
    if (!options.headers) {
        options.headers = new Headers({ Accept: 'application/json' });
    }
    // add your own headers here
    options.headers.set('X-Custom-Header', 'foobar');
    return fetchUtils.fetchJson(url, options);
}
const dataProvider = jsonServerProvider('http://jsonplaceholder.typicode.com', httpClient);
 
render(
    <Admin dataProvider={dataProvider} title="Example Admin">
       ...
    </Admin>,
    document.getElementById('root')
);

Now all the requests to the REST API will contain the X-Custom-Header: foobar header.

Tip: The most common usage of custom headers is for authentication. fetchJson has built-on support for the Authorization token header:

const httpClient = (url, options = {}) => {
    options.user = {
        authenticated: true,
        token: 'SRTRDFVESGNJYTUKTYTHRG'
    }
    return fetchUtils.fetchJson(url, options);
}

Now all the requests to the REST API will contain the Authorization: SRTRDFVESGNJYTUKTYTHRG header.

Note: In case of REST verb "CREATE" consider that the response body is the same as the request body but with the object ID injected .

case CREATE:
return { data: { ...params.data, id: json.id } };

This is because of backwards compatibility compliance.

License

This data provider is licensed under the MIT License, and sponsored by marmelab.