PostgREST Data Provider For React-Admin

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

Installation

npm install --save @promitheus/ra-data-postgrest

NOTE: When using RA 3.x.x, use the data-provider 1.x.x. For RA >= 4.1.x use the data-provider starting from 1.2.x.

REST Dialect

This Data Provider fits REST APIs using simple GET parameters for filters and sorting. This is the dialect used for instance in PostgREST.

Note: The PostgREST data provider expects the API to include a Content-Range header in the response to getList calls. The value must be the total number of resources in the collection. This allows react-admin to know how many pages of resources there are in total, and build the pagination controls.

Content-Range: posts 0-24/319

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: Content-Range

Usage

// in src/App.js
import React from 'react';
import { Admin, Resource } from 'react-admin';
import postgrestRestProvider from '@promitheus/ra-data-postgrest';

import { PostList } from './posts';

const App = () => (
    <Admin dataProvider={postgrestRestProvider('http://path.to.my.api/')}>
        <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 postgrestRestProvider from '@promitheus/ra-data-postgrest';

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 = postgrestRestProvider('http://localhost:3000', 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.

Using authProvider

This package also comes with an authProvider for react-admin which enables you to enable authentification. The provider is designed to work together with subzero-starter-kit. This starter kit sends the JWT within a session cookie. The authProvider expects that. If you want to use postgREST without the starter kit you'll need to write your own. Feel free to contribute!

With one of the starter kits it is very easy to use the authProvider:

// in src/App.js
import React from 'react';
import { Admin, Resource } from 'react-admin';
import postgrestRestProvider, {
    authProvider,
} from '@promitheus/ra-data-postgrest';

import { PostList } from './posts';

const App = () => (
    <Admin
        dataProvider={postgrestRestProvider('http://path.to.my.api/')}
        authProvider={authProvider}
    >
        <Resource name="posts" list={PostList} />
    </Admin>
);

export default App;

Special Filter Feature

As postgRest allows several comparators, e.g. ilike, like, eq... The dataProvider is designed to enable you to specify the comparator in your react filter component:

<Filter {...props}>
    <TextInput label="Search" source="post_title@ilike" alwaysOn />
    <TextInput label="Search" source="post_author" alwaysOn />
    // some more filters
</Filter>

One can simply append the comparator with an @ to the source. In this example the field post_title would be filtered with ilike whereas post_author would be filtered using eq which is the default if no special comparator is specified.

RPC Functions

Given a RPC call as GET /rpc/add_them?post_author=Herbert HTTP/1.1, the dataProvider allows you to filter such endpoints. As they are no view, but a SQL procedure, several postgREST features do not apply. I.e. no comparators such as ilike, like, eq are applicable. Only the raw value without comparator needs to be send to the API. In order to realize this behavior, just add an "empty" comparator to the field, i.e. end source with an @ as in the example:

<Filter {...props}>
    <TextInput label="Search" source="post_author@" alwaysOn />
    // some more filters
</Filter>

Compound primary keys

If one has data resources without primary keys named id, one will have to define this specifically. Also, if there is a primary key, which is defined over multiple columns:

const dataProvider = postgrestRestProvider(
    API_URL,
    fetchUtils.fetchJson,
    'eq',
    new Map([
        ['some_table', ['custom_id']],
        ['another_table', ['first_column', 'second_column']],
    ])
);

Developers notes

The current development of this library was done with node v19.10 and npm 8.19.3. In this version the unit tests and the development environment should work.

License

This data provider is licensed under the MIT License and sponsored by raphiniert.com.